Low boiler pressure


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Old 02-11-10, 10:36 AM
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Low boiler pressure

NJ Trooper...enjoy reading your replies. Thanks.

So, I have a Teledyne Laars Mini Therm (JV75?) 14 years old. Pressure reads 5 lbs @ 120-140 F. Is the pressure too low & how do I increase if necessary. (BTW...pressure was at 5 when boiler shut down for unknown reason overnight.)

Thanks to all.
Dobbs
 

Last edited by NJT; 02-14-10 at 10:32 AM.
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Old 02-11-10, 08:11 PM
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Hi Dobbs, thanks!

There should be a pipe leading from your domestic water supply over to the boiler. On this pipe should be a manual shutoff valve, followed by (possibly, optional) a 'backflow preventer', and followed by a 'pressure reducing valve' ... a bell shaped thingy...

Check and see if the manual shutoff valve is open or closed. If it's open, and you have low pressure, you might have a defective pressure reducing valve...

We would need to see pictures to give more than a 'generic' explanation... free account / Image hosting, free photo sharing & video sharing at Photobucket / upload pics there / drop a link here for us to view the album.

Why the pressure is low in the first place is another question that will need answering... maybe a small leak somewhere...

And if you've read many of my posts, you will know how much I distrust boiler gauges... yours could be inaccurate.

Why the burners shut down? good question... let's see the system and go from there.
 
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Old 02-14-10, 10:26 AM
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Manual supply valve is "Open". PRV has some type of lever/tab which I'm not familiar with. Anyway, here's some pics.
Thanks



 
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Old 02-14-10, 11:23 AM
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I'm afraid yer gonna be sorry you asked...

When you use PRV as an acronym, that can refer to two things on the boiler... Pressure RELIEF Valve, or Pressure REDUCING Valve, so we'll spell it out so no confusion.

Your Pressure Reducing Valve has that tab, or lever, on it for the purpose of bypassing the regulating part of the valve. Let's you get water into the boiler faster for initial filling, or after servicing.

If your manual shutoff valve is open (you said it was), and you have 5 PSI in the boiler, then the Reducing valve is either plugged up, or misadjusted. They should maintain 12-15 PSI in your system.

Before anything else, make sure that you can get water back into the boiler... operate the fast fill lever on the reducing valve and listen for water flow... watch the gauge... make sure you have a way of getting water back in, or you will have to replace the reducing valve FIRST... If you can get water into the system, continue:

Following are the instructions for checking/charging your expansion tank. If you don't do this, and the tank is low on air charge or has a broken bladder, soon after you fire up the boiler after adding water, the relief valve will open and spew hot water all over the floor.

========================

1. Shut off boiler and allow to cool to under 100F.

2. Shut off water supply line to boiler.

3. Drain only enough water from the boiler drain to drop the system pressure to ZERO.
Do NOT completely drain the system!

4. With an ACCURATE tire pressure gauge, check the air charge in the tank on the air valve opposite the end of the tank that's connected to the system. If ANY water comes out of the air valve, the bladder inside the tank is shot and the tank needs replaced. If no water comes out the air valve, and the pressure is less than 12-15 PSI, continue to step 5. If the pressure is OK, turn the water supply to the boiler back on and repressurize the system, turn the power back on to the boiler, no service is necessary.

5. Using a bicycle pump, or a small air compressor, add air to the tank until you have 15 PSI air charge.

6. Check the boiler pressure gauge again, and if it has risen off ZERO, drain some more water from the boiler drain until it is again at ZERO.

7. Check the air charge on the tank again. If it is below 15 PSI, add air to the tank until it is at 15 PSI.

8. Repeat steps 6 and 7 until the boiler stays at ZERO and the tank stays at 15 PSI. At this point, the tank is properly recharged and the water supply can be turned on to re-pressurize the system, turn the power on to boiler and return to service.

========================

At this point, your boiler should be COOL/COLD, and the gauge should be reading 12-15 PSI. With the tank properly charged with air, your pressure should climb when heated to maybe 18-20 PSI...

more... about why yer gonna be sorry you asked!
 
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Old 02-14-10, 11:42 AM
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Referring to the above pic:

1. This is a SYSTEM BYPASS valve, and the Laars boilers require this valve to be OPEN. So, open it, and leave it open.

Has your boiler ever made any weird sounds, noises, etc? If so, it's because that valve is closed. One drawback to this is that the flow through the baseboards/radiators will be reduced, and the home may not heat up as quickly as it used to, but it will heat up and is something you just need to live with.

If you have the manual for the boiler, read it, and you will see that it needs to be open. If you don't have the manual, go to the Laars website and download it.

2. This 'streaking' on your flue pipe is a bad thing. That indicates that you have significant flue gas condensation occuring in the chimney, and probably in the boiler as well. This problem might be mitigated somewhat by opening the bypass valve...

3. I'm not a 'gas-head'... but your gas piping not only is probably not up to code, but those flex line stretched across the front of the water heater and boiler are dangerous... I'm hoping that one of the guys who is more up on codes and stuff will elaborate on that for me.

I didn't circle it, but fire codes require 18" from the flue pipe to any combustible, and those cardboard boxes are combustibles... as is the drywall behind the flue pipe...

Sorry you asked yet?
 
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Old 02-14-10, 09:20 PM
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Originally Posted by NJ Trooper View Post

Sorry you asked yet?
No...it's been this way for 14 years! It's just time to do something about it. I'll reply to your post soon, and welcome some more advise/abuse.
 

Last edited by NJT; 02-15-10 at 03:18 PM.
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Old 02-16-10, 03:51 PM
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Originally Posted by NJ Trooper View Post


Referring to the above pic:

2. This 'streaking' on your flue pipe is a bad thing. That indicates that you have significant flue gas condensation occuring in the chimney, and probably in the boiler as well. This problem might be mitigated somewhat by opening the bypass valve...

Sorry you asked yet?
Let's discuss #2 a little more. I have replaced the flue pipe twice in 14 years due to complete rust through & the boiler "hood" once a couple years ago for the same reason. I did open the bypass valve the other day, but won't be back in town to check on it for another day or so. I hope the bypass being close IS the reason for the "streaking" which has rusted out the flue a couple times in the past. I figured the sold those pieces at HD because people needed to replace them.
Can you explain the purpose of the bypass and how it effects things?

I'll try adjusting the air pressure when I get back and let you know what I find. What exactly will the difference in operation or performance be with pressure at say 12-15psi vs. 5psi.

Thanks again!
 
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Old 02-16-10, 04:55 PM
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I'm not sure if you've ever told us what kind of heat emitters are in the home? Fin-tube baseboard? Cast-iron rads? please describe, it might have some bearing on the following explanation.

The streaking you see is of course caused by the water in the flue gases condensing, and mixing with the acids that are formed during combustion. Usually when it occurs in the chimney it's because the chimney is on an outside wall (is it?) and it's a LARGE flue liner... in the olden days, flue gases were a lot hotter than they are in these enlightened? times. (more efficient boilers). So when the gases hit those cool surfaces, condensation occurs.

Yes, this is definitely what rotted out your flue pipe and hood... it often occurs INSIDE the boiler as well... bad news.

Yes, the stuff does need to be replaced from time to time, even if there's no condensation. The stuff they sell at the home centers is usually 30 gauge, and is not exactly the right stuff for flue pipes. It's real intent is for air ducts. Flue pipe should generally be 24 gauge... stronger, lasts longer, etc... probably other reasons too (maybe even local building codes). Real supply houses will stock the 24 gauge stuff. If you have a wood stove store nearby, that's a good place to look also, but they usually stock the black painted stuff which costs a bit more. (and maybe 22 gauge as well)

Can you explain the purpose of the bypass and how it effects things?
On YOUR boiler, which is a 'copper tube heat exchanger' type, the SYSTEM bypass is there mostly to ensure that there is adequate flow through the boiler. If your type of boiler has real lazy flow, hot spots can develop, mineral deposits will form more easily, and the manufacturer won't warranty the boiler (I guess yours 'made it' though).

Bypass piping is used to PROTECT the boiler from condensation as well... even with non copper boilers. There are two types, a BOILER bypass, and a SYSTEM bypass.

BOILER bypass protects the boiler by DECREASING the flow through the boiler, but the flow in the SYSTEM stays the same. This type of bypass is on the boiler side of the circulation pump. It protects the boiler by allowing it to get hotter, faster. Less flow through the boiler means it is not getting as large a volume of cool return water from the system.

SYSTEM bypass will protect the boiler in a similar fashion, by redirecting some of the flow from the boiler directly back into the boiler... again, it gets hot faster, but there is a price... the flow through the SYSTEM is decreased, and this can often lead to unbalanced heating.

You may find this to be true, in which case you can _probably_ partially close the bypass valve... but try to leave it open a fair amount... ball valves like you have are not intended for throttling flows, but you don't have a choice... it should have been a good quality globe valve, or a plug valve... and the fact that it hasn't died yet indicates that you might actually already have enough flow through the boiler... it would be whistling like a teapot, and making all kinds of noises if you didn't. But, you do want to leave it partially open.

Opening that valve might NOT help the condensation in the flue pipe. It might HELP, but probably not cure it. If your chimney is cold and too large, nothing really will help except installing a liner in the flue pipe... something you will probably be REQUIRED to do by code when it comes time to replace the boiler.

Physics lesson next...
 
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Old 02-16-10, 05:22 PM
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What exactly will the difference in operation or performance be with pressure at say 12-15psi vs. 5psi.
First, everybody that has read more than a few of my rants knows how much I hate gauges. They LIE. So one of the things that should probably happen is that you verify the accuracy of the gauge. This can be done by screwing a known good gauge on a hose adapter to any of the boiler drains and opening the drain valve. Compare the reading of the known good to the boiler gauge.

Did you say physics? ooops, no, that was me, sorry!

Picture a vertical piece of pipe, the height of your house.

Q: How much pressure would it take to push the water out the top of the pipe if you fed water into the bottom?

A: 0.432 PSI per FOOT. (inversely, ONE PSI will raise the water in the pipe about 2.31 feet)

That's the law. Even O'bama's administration can't change it.

From your boiler to the highest radiator/baseboard is what? Two story house? maybe 20 feet? To get water in your system up to the top of the highest radiators, you would need 20 X 0.432 PSI. Which is 8.64 PSI. And at that pressure, the top of the system would be at ZERO PSI. You NEED pressure in the system to prevent the water flashing to steam and to keep air dissolved in the water rather than forming bubbles. So we generally add 3-4 PSI 'headroom'. Now, we're at 11.64-12.64 PSI... does that number look familiar? The taller structures need progressively higher pressure to raise the water in the system and maintain pressure at the top of the system.

So, you think you have 5 PSI in your system? How high can the water go? 5 / 0.431 = 11.6 Feet... but remember that you need the headroom... at least 3 PSI. 3 PSI is equal to 2.31 (feet per PSI) X 3 = 6.93 FEET. Subtract that from 11.6 and you have the ability to operate your system up to a height above the boiler of maybe FIVE FEET. That ain't even gonna get the water outta yer basement!

This reasoning is why I suspect your gauge us pooched... if you REALLY had 5 PSI in your system, you wouldn't be asking how to raise the pressure, you would be asking "Whycome every time my heat runs does it sound like Niagra Falls in my pipes?"

ANOTHER reason for the MINIMUM pressure spec of 12 PSI in a system has to do with the PUMPS. There are lots of technical terms... like NPSH and Vapor Pressure, and stuff like that... but suffice it to say that without enough pressure in the system, the circulator pump can CAVITATE (google it) and not pump any water and destroy itself. ALSO, when the pump is running, there is a pressure difference across the pump. This pressure difference can be (and most often is, depending on how the system is plumbed) SUBTRACTED from the existing system pressure. This often means that even the 4 PSI of 'headroom' isn't enough. (there are ways to pipe systems so that the pressure ADDS to the system pressure, google "Pumping Away" for more info, if you can stand all this info overload!) [EDIT: I just looked at your pics again, and it does appear that your system IS 'pumping away'... Praise Be!]

BOTTOM LINE:

First verify your gauge is accurate.

Next, make sure your expansion tank is in good shape with the proper air charge and the bladder intact, and make sure you have a minimum of 12 PSI in the system.

whew! I need Beer 4U2
 
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Old 02-17-10, 07:40 AM
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Trooper, This is a great physics lesson

Emil
 
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Old 02-19-10, 01:39 PM
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Originally Posted by NJ Trooper View Post
I'm not sure if you've ever told us what kind of heat emitters are in the home? Fin-tube baseboard? Cast-iron rads? please describe, it might have some bearing on the following explanation.

OK. Here's some more info. that might help you help me! I have radiant floor heat between the joists.

The streaking you see is of course caused by the water in the flue gases condensing, and mixing with the acids that are formed during combustion. Usually when it occurs in the chimney it's because the chimney is on an outside wall (is it?) and it's a LARGE flue liner... in the olden days, flue gases were a lot hotter than they are in these enlightened? times. (more efficient boilers). So when the gases hit those cool surfaces, condensation occurs.

The chimney is in an unheated garage going up through the uninsulated roof.

Yes, this is definitely what rotted out your flue pipe and hood... it often occurs INSIDE the boiler as well... bad news.

Yes, the stuff does need to be replaced from time to time, even if there's no condensation. The stuff they sell at the home centers is usually 30 gauge, and is not exactly the right stuff for flue pipes. It's real intent is for air ducts. Flue pipe should generally be 24 gauge... stronger, lasts longer, etc... probably other reasons too (maybe even local building codes). Real supply houses will stock the 24 gauge stuff. If you have a wood stove store nearby, that's a good place to look also, but they usually stock the black painted stuff which costs a bit more. (and maybe 22 gauge as well)



On YOUR boiler, which is a 'copper tube heat exchanger' type, the SYSTEM bypass is there mostly to ensure that there is adequate flow through the boiler. If your type of boiler has real lazy flow, hot spots can develop, mineral deposits will form more easily, and the manufacturer won't warranty the boiler (I guess yours 'made it' though).

Bypass piping is used to PROTECT the boiler from condensation as well... even with non copper boilers. There are two types, a BOILER bypass, and a SYSTEM bypass.

BOILER bypass protects the boiler by DECREASING the flow through the boiler, but the flow in the SYSTEM stays the same. This type of bypass is on the boiler side of the circulation pump. It protects the boiler by allowing it to get hotter, faster. Less flow through the boiler means it is not getting as large a volume of cool return water from the system.

SYSTEM bypass will protect the boiler in a similar fashion, by redirecting some of the flow from the boiler directly back into the boiler... again, it gets hot faster, but there is a price... the flow through the SYSTEM is decreased, and this can often lead to unbalanced heating.

You may find this to be true, in which case you can _probably_ partially close the bypass valve... but try to leave it open a fair amount... ball valves like you have are not intended for throttling flows, but you don't have a choice... it should have been a good quality globe valve, or a plug valve... and the fact that it hasn't died yet indicates that you might actually already have enough flow through the boiler... it would be whistling like a teapot, and making all kinds of noises if you didn't. But, you do want to leave it partially open.

Opening that valve might NOT help the condensation in the flue pipe. It might HELP, but probably not cure it. If your chimney is cold and too large, nothing really will help except installing a liner in the flue pipe... something you will probably be REQUIRED to do by code when it comes time to replace the boiler.

I have opened the bypass valve.

Physics lesson next...
Thanks again, will wait for your reply.
Dobbs
 
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Old 02-19-10, 01:48 PM
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Originally Posted by NJ Trooper View Post
First, everybody that has read more than a few of my rants knows how much I hate gauges. They LIE. So one of the things that should probably happen is that you verify the accuracy of the gauge. This can be done by screwing a known good gauge on a hose adapter to any of the boiler drains and opening the drain valve. Compare the reading of the known good to the boiler gauge.

Did you say physics? ooops, no, that was me, sorry!

Picture a vertical piece of pipe, the height of your house.

Q: How much pressure would it take to push the water out the top of the pipe if you fed water into the bottom?

A: 0.432 PSI per FOOT. (inversely, ONE PSI will raise the water in the pipe about 2.31 feet)

That's the law. Even O'bama's administration can't change it.

That wouldn't keep them from trying when we aren't looking!

From your boiler to the highest radiator/baseboard is what? Two story house? maybe 20 feet? To get water in your system up to the top of the highest radiators, you would need 20 X 0.432 PSI. Which is 8.64 PSI. And at that pressure, the top of the system would be at ZERO PSI. You NEED pressure in the system to prevent the water flashing to steam and to keep air dissolved in the water rather than forming bubbles. So we generally add 3-4 PSI 'headroom'. Now, we're at 11.64-12.64 PSI... does that number look familiar? The taller structures need progressively higher pressure to raise the water in the system and maintain pressure at the top of the system.

So, you think you have 5 PSI in your system? How high can the water go? 5 / 0.431 = 11.6 Feet... but remember that you need the headroom... at least 3 PSI. 3 PSI is equal to 2.31 (feet per PSI) X 3 = 6.93 FEET. Subtract that from 11.6 and you have the ability to operate your system up to a height above the boiler of maybe FIVE FEET. That ain't even gonna get the water outta yer basement!

OK, so my water goes down instead of up...is 5 psi enough for this application?

This reasoning is why I suspect your gauge us pooched... if you REALLY had 5 PSI in your system, you wouldn't be asking how to raise the pressure, you would be asking "Whycome every time my heat runs does it sound like Niagra Falls in my pipes?"

ANOTHER reason for the MINIMUM pressure spec of 12 PSI in a system has to do with the PUMPS. There are lots of technical terms... like NPSH and Vapor Pressure, and stuff like that... but suffice it to say that without enough pressure in the system, the circulator pump can CAVITATE (google it) and not pump any water and destroy itself. ALSO, when the pump is running, there is a pressure difference across the pump. This pressure difference can be (and most often is, depending on how the system is plumbed) SUBTRACTED from the existing system pressure. This often means that even the 4 PSI of 'headroom' isn't enough. (there are ways to pipe systems so that the pressure ADDS to the system pressure, google "Pumping Away" for more info, if you can stand all this info overload!) [EDIT: I just looked at your pics again, and it does appear that your system IS 'pumping away'... Praise Be!]

BOTTOM LINE:

First verify your gauge is accurate.

Gauge IS accurate. Checked it without a hose bib type. Water that dripped out was rusty.


Next, make sure your expansion tank is in good shape with the proper air charge and the bladder intact, and make sure you have a minimum of 12 PSI in the system.

No water, just air, but not sure of the psi yet...

whew! I need Beer 4U2
OK. One other thing....over the last few days, the "onboard" circuit breaker has needed to be reset several times. As soon as the little red dot is pressed, it fires right up, but not sure what is causing this? Just started recently. (This week)
 
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Old 02-19-10, 04:59 PM
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I have radiant floor heat between the joists.
Huh? Then there must be more to your system piping that we can't see in the pics... Is there a 'mixing valve' and another pump somewhere that we can't see?

my water goes down instead of up...is 5 psi enough for this application?
What you mean? The boiler is ABOVE the system piping?

You should still maintain 12 PSI minimum if for no other reason than to keep the air bubbles from forming... but it is possible that in some cases, you could run at 5 PSI without major troubles. BUT ... take a look at the tag on you Pressure Reducing Valve. You will see that the adjustment range does not go down as far as 5 PSI. I've tried using them for a different application at lower pressures, and can tell you that they simply don't work. They drift all over the place. This tells me that the pressure you have is not 'by design', but 'by fault' of the reducing valve, it's probably plugged.

Gauge IS accurate. Checked it without a hose bib type. Water that dripped out was rusty.
Good to know. Don't worry about the rusty water, that's normal. Bet it stinks too...

No water, just air, but not sure of the psi yet...
Also good that you don't get water. If you have an accurate tire pressure gauge, take a reading and let us know what you find.

One other thing....over the last few days, the "onboard" circuit breaker has needed to be reset several times. As soon as the little red dot is pressed, it fires right up, but not sure what is causing this? Just started recently. (This week)
Circuit breaker on the controls inside the front panel box?

Can you show me a picture of this 'circuit breaker'?

Can you find a FULL model number anywhere on the unit?
 

Last edited by NJT; 02-19-10 at 05:19 PM.
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Old 02-19-10, 06:39 PM
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Originally Posted by NJ Trooper View Post
Huh? Then there must be more to your system piping that we can't see in the pics... Is there a 'mixing valve' and another pump somewhere that we can't see?
Don't know of any 'mixing valve' or another pump. Entire house is on a single zone.



What you mean? The boiler is ABOVE the system piping?
Yes. The piping is in the garage and goes under the floor in the single story house.

You should still maintain 12 PSI minimum if for no other reason than to keep the air bubbles from forming... but it is possible that in some cases, you could run at 5 PSI without major troubles. BUT ... take a look at the tag on you Pressure Reducing Valve. You will see that the adjustment range does not go down as far as 5 PSI. I've tried using them for a different application at lower pressures, and can tell you that they simply don't work. They drift all over the place. This tells me that the pressure you have is not 'by design', but 'by fault' of the reducing valve, it's probably plugged.
Pressure reducing valve is rated 10-25, preset at 12 from the manufacturer. Moved the little tab on the side to the opposite position, but didn't seem to do anything. I think you said this tab was to manually bypass the pressure reduction?



Good to know. Don't worry about the rusty water, that's normal. Bet it stinks too...



Also good that you don't get water. If you have an accurate tire pressure gauge, take a reading and let us know what you find.
OK. Maybe here's an issue...4 psi.



Circuit breaker on the controls inside the front panel box?
It's located on the right side behind the gas valve on the front of the boiler.

Can you show me a picture of this 'circuit breaker'?




Can you find a FULL model number anywhere on the unit?
It's JVT75NDI
Also, along with the circuit breaker issue...the pilot light has gone out twice in the last week. This is not caused by any type of breeze or draft. It's pretty protected.

While it's firing...I took a look up inside where the flames are heating the fins, etc. Looks to be some type of buildup or something in there. Sorta looks like coals in a fire. Is this typical.

Sooooooooo....I'm thinking about going with a Rinnai wall mount boiler and just scrapping this headache.
Any experience with those?

Thanks,
Dobbs
 
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Old 02-19-10, 07:04 PM
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I have to depart for a while... but I wanted to get this out there for you before I did...

That's NOT a circuit breaker ... well, it is, but not as you know it... I believe that may be the ROLLOUT switch. It's a temperature activated device that senses when there's not enough draft through the system, and the flames actually begin to 'roll out' of the boiler. This can also indicate that SOME FLUE GAS IS LEAKING INTO YOUR HOME I pray that you have functioning CO detectors in the home... please tell me you do!

No, I don't think the 'coals' you see are typical... it sounds as though the condensation we spoke of earlier has partially plugged up the flue passes in the boiler...

Do you have the manual for your boiler? I can point you to a download (if you can't find it...)...

I'll be back later (I think)

CHECK THOSE CO DETECTORS, NOW!
 
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Old 02-19-10, 08:13 PM
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Originally Posted by NJ Trooper View Post
I have to depart for a while... but I wanted to get this out there for you before I did...

That's NOT a circuit breaker ... well, it is, but not as you know it... I believe that may be the ROLLOUT switch. It's a temperature activated device that senses when there's not enough draft through the system, and the flames actually begin to 'roll out' of the boiler. This can also indicate that SOME FLUE GAS IS LEAKING INTO YOUR HOME I pray that you have functioning CO detectors in the home... please tell me you do!

No, I don't think the 'coals' you see are typical... it sounds as though the condensation we spoke of earlier has partially plugged up the flue passes in the boiler...

Do you have the manual for your boiler? I can point you to a download (if you can't find it...)...

I'll be back later (I think)

CHECK THOSE CO DETECTORS, NOW!
Alright...thanks again for the info. Yes, I did find the manual online. I'm thinking I have blocked heat exchangers causing rollout, causing the rollout switch (breaker) to trip, causing the boiler to shut down, causing the inside temp. to drop, causing us to leave the refrigerator door open to warm up the house, causing my wife to shake her head every time I head to the garage or back on the forum. Beer 4U2

Might have to take the boiler apart tomorrow to clean the heat exchangers. I think they are plugged.

CO detector.....hmmm. No wonder I sleep well at night. I'm probably dead most of the time. No, I don't have any, but might put that on my list?

I do finally have 12-15 psi in the tank & in the boiler.

Thanks,
Dobbs
 
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Old 02-19-10, 08:23 PM
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Originally Posted by Dobber1 View Post
causing my wife to shake her head every time I head to the garage or back on the forum. Beer 4U2
She must be related to my wife......

Beer 4U2
 
  #18  
Old 02-19-10, 08:31 PM
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Getting back to my earlier post... before you do ANYTHING else, you need to clean that boiler out. If you've got 'coals' sitting in the flue passes, it's a real good indication that the boiler is plugged, that and the fact that your rollout switch is tripping. This is before anything else. It must be done.

Don't know of any 'mixing valve' or another pump. Entire house is on a single zone.
So your system is pumping direct from the boiler (full temp) into the radiant tubing?

How is your tubing applied? Is it stapled to the bottom of the floor with heat transfer plates? Hanging in the joist space with insulation underneath?

MOST radiant underfloor limits the water temp to less than 120, or 100... and there's usually a mixing valve and another pump after it. This allows the boiler to operate at normal 'higher' temps, and the tubing to receive proper temp water.

What do you generally see on the temp side of the gauge?

Yes. The piping is in the garage and goes under the floor in the single story house.
I was fooled I guess by the fact that the piping appears to go up to the ceiling out of the boiler.

Pressure reducing valve is rated 10-25, preset at 12 from the manufacturer. Moved the little tab on the side to the opposite position, but didn't seem to do anything. I think you said this tab was to manually bypass the pressure reduction?
Yes, that's correct... if you aren't getting any feedwater even when moving the 'fast fill' lever, then that thing is plugged up. You need to replace it.

Before you do this, correct the air charge in the tank.

You can 'backfill' the boiler with a garden hose. You will need a 'sex changer' to do so. A washing machine hose works great for this. Hook the garden hose up to one of the boiler drains (any one). Leave the fitting loose at the boiler end for now. Turn on the water SLOWLY and let the air get pushed out of the hose so it doesn't end up in the system, then tighten the fitting at the boiler. Now, S L O W L Y! open the boiler drain and backfeed the water into the boiler. Watch the gauge and stop when it gets to 12 PSI. Close the valves and remove the hose!

OK. Maybe here's an issue...4 psi.
I knew that... those bladders are good, but if you look at the manufacturers data sheets, even they will tell you that 1-2 PSI per year pressure loss through the bladder is not unexpected. This is the same reason that children's baloons lose air, it passes right through the rubber. They are not impermeable. This is why they should be checked at a MINIMUM every two years. But NOBODY does... well, almost nobody.

The proper air charge in the tank should MATCH the COLD pressure on the boiler. So, as it stands, you have 4-5 PSI in the boiler, and that matches the tank... another BUT... when you measure the pressure on the air side with pressure on the water side, you will NOT get a proper reading. You could very well have LESS than 4 PSI charge of air, and what you are reading is the boiler water pressure. Checking with pressure on the boiler side will give you the HIGHER of the two pressures. I posted earlier the instructions for charging the tank.
 
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Old 02-19-10, 08:38 PM
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She must be related to my wife......
Maybe you guys then can understand that my wife shakes her head more than she doesn't!

I was typing that last post before I seen yer guys replies... so it may seem 'out of the time contiuum'.

How did you get the water into the boiler?

and you followed the instructions to air charge the tank from the earlier post? I ask because I am looking for feedback on that procedure... how it works, anything that might have confused, or could be better written...

By the way, the fact that your boiler is in the garage may have actually SAVED your life!
 
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Old 02-19-10, 09:20 PM
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Speakin' of Safety...

The refractory material in the heat exchanger area has been linked to the big C ... PLEASE, when you clean it, don't disturb those boards... and wear a good filter mask! wouldn't be a bad idea at all to leave the garage door open, and maybe even a fan to blow particles out the door. If you use a vacuum, hopefully you have a long enough hose to place the vacuum canister outside so the exhaust doesn't blow around inside. (hint: pool cleaning tubing works well as an extension hose, and it's pretty cheap). I believe this also may be the reason the manual recommends using a spritz of water... to keep the particulate out of the air.
 
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Old 02-20-10, 10:04 AM
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Originally Posted by NJ Trooper View Post
Getting back to my earlier post... before you do ANYTHING else, you need to clean that boiler out. If you've got 'coals' sitting in the flue passes, it's a real good indication that the boiler is plugged, that and the fact that your rollout switch is tripping. This is before anything else. It must be done.

I'd really like to wait a day or two for some better weather.
[IMG][/IMG]


So your system is pumping direct from the boiler (full temp) into the radiant tubing?
I believe this to be true, unless the mixing happens inside the wall?

How is your tubing applied? Is it stapled to the bottom of the floor with heat transfer plates? Hanging in the joist space with insulation underneath?

MOST radiant underfloor limits the water temp to less than 120, or 100... and there's usually a mixing valve and another pump after it. This allows the boiler to operate at normal 'higher' temps, and the tubing to receive proper temp water.

What do you generally see on the temp side of the gauge?
130-140



I was fooled I guess by the fact that the piping appears to go up to the ceiling out of the boiler.
Up out of the boiler, then 90s into the wall and down through the floor.



Yes, that's correct... if you aren't getting any feedwater even when moving the 'fast fill' lever, then that thing is plugged up. You need to replace it.
Great!

Before you do this, correct the air charge in the tank.
Done.

You can 'backfill' the boiler with a garden hose. You will need a 'sex changer' to do so. A washing machine hose works great for this. Hook the garden hose up to one of the boiler drains (any one). Leave the fitting loose at the boiler end for now. Turn on the water SLOWLY and let the air get pushed out of the hose so it doesn't end up in the system, then tighten the fitting at the boiler. Now, S L O W L Y! open the boiler drain and backfeed the water into the boiler. Watch the gauge and stop when it gets to 12 PSI. Close the valves and remove the hose!
This is all if we assume the PRV is actually plugged, correct?



I knew that... those bladders are good, but if you look at the manufacturers data sheets, even they will tell you that 1-2 PSI per year pressure loss through the bladder is not unexpected. This is the same reason that children's baloons lose air, it passes right through the rubber. They are not impermeable. This is why they should be checked at a MINIMUM every two years. But NOBODY does... well, almost nobody.

The proper air charge in the tank should MATCH the COLD pressure on the boiler. So, as it stands, you have 4-5 PSI in the boiler, and that matches the tank... another BUT... when you measure the pressure on the air side with pressure on the water side, you will NOT get a proper reading. You could very well have LESS than 4 PSI charge of air, and what you are reading is the boiler water pressure. Checking with pressure on the boiler side will give you the HIGHER of the two pressures. I posted earlier the instructions for charging the tank.
Thanks again for all your insight.
Dobbs
 
  #22  
Old 02-20-10, 10:07 AM
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Originally Posted by NJ Trooper View Post
Speakin' of Safety...

The refractory material in the heat exchanger area has been linked to the big C ... PLEASE, when you clean it, don't disturb those boards... and wear a good filter mask! wouldn't be a bad idea at all to leave the garage door open, and maybe even a fan to blow particles out the door. If you use a vacuum, hopefully you have a long enough hose to place the vacuum canister outside so the exhaust doesn't blow around inside. (hint: pool cleaning tubing works well as an extension hose, and it's pretty cheap). I believe this also may be the reason the manual recommends using a spritz of water... to keep the particulate out of the air.
I'm really beginning to like my choices.....freezing to death, "C" from coal dust or CO poisoning. Maybe the president would like to come to dinner! Beer 4U2
 
  #23  
Old 02-20-10, 10:13 AM
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Originally Posted by NJ Trooper View Post
Maybe you guys then can understand that my wife shakes her head more than she doesn't!

I was typing that last post before I seen yer guys replies... so it may seem 'out of the time contiuum'.

How did you get the water into the boiler?
Just opened the main water supply valve. Any way to tell if it's not full? I do have a couple relief mechanisms on top of both the inlet and outlet pipes coming from the boiler. Bleeders of some type?

and you followed the instructions to air charge the tank from the earlier post? I ask because I am looking for feedback on that procedure... how it works, anything that might have confused, or could be better written...

By the way, the fact that your boiler is in the garage may have actually SAVED your life!
It's 66 degrees in here right now and comfy! Being a winter recreationalist...cold is good.

Dobbs
 
  #24  
Old 02-20-10, 10:32 AM
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I'd really like to wait a day or two for some better weather.
Uhhhh, yeah... good idea! You didn't tell us you lived in Siberia!

What do you generally see on the temp side of the gauge?
130-140
Too low... condensing 100% of the time!

If you DO replace the boiler definitely look into the MOD/CON (modulating / condensing)

This is all if we assume the PRV is actually plugged, correct?
Correct, but:

How did you get the water into the boiler?
Just opened the main water supply valve. Any way to tell if it's not full? I do have a couple relief mechanisms on top of both the inlet and outlet pipes coming from the boiler. Bleeders of some type?
I must have missed something... in your pic, the water supply valve IS open (handle parallel to the pipe). Is there ANOTHER valve upstream of what can be seen in the pic?

Those 'mechanisms' are probably float type automatic air vents... small brass cans with a cap on top?
 
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Old 02-20-10, 06:54 PM
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Originally Posted by NJ Trooper View Post
Uhhhh, yeah... good idea! You didn't tell us you lived in Siberia!

BTW....I do live in Siberia....or Colorado?



Too low... condensing 100% of the time!

Maxes out at 155 & kicks back on at 125 degrees. Looks like the mfr. high limit is 190. Could I get 190 if the fins were clean and the flame could actually heat the pipes vs. the coals?


If you DO replace the boiler definitely look into the MOD/CON (modulating / condensing)



Correct, but:



I must have missed something... in your pic, the water supply valve IS open (handle parallel to the pipe). Is there ANOTHER valve upstream of what can be seen in the pic?

No...When I re-opened the valve after charging the tank I was at 12 psi.


Those 'mechanisms' are probably float type automatic air vents... small brass cans with a cap on top?
Yes, that's what I think they are?

Thanks,
Dobbs
 
  #26  
Old 02-20-10, 09:00 PM
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You really need a mixing valve to provide the proper temperature for the radiant floor while also allowing the boiler temperature to rise to a proper level.
 
  #27  
Old 02-20-10, 09:04 PM
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Maxes out at 155 & kicks back on at 125 degrees. Looks like the mfr. high limit is 190. Could I get 190 if the fins were clean and the flame could actually heat the pipes vs. the coals?
Probably not... boiler is going to kick off when the thermostat is satisfied. The boiler will likely heat the water FASTER though, but it will most likely still tend to kick off at the same temp. Thing is, that's to hot for in-floor... water temp to the radiant tubing should perhaps be around 120 or so... maybe a little more with the way yours is installed... if you had the metal plates, you definitely wouldn't want more than 120 water... but if the tubing is 'floating' in the joist space your water temp can, and maybe should, be a bit higher.

No...When I re-opened the valve after charging the tank I was at 12 psi.
I guess maybe the reducing valve was 'stuck' and got un-stuck when the water was turned back on. Keep an eye on that pressure gauge now, because if there was 'crud' in the water line and it got under the valve seat, the reducing valve may leak slowly and over-pressure the boiler. If you see it creeping up, close the manual feed valve and see if that stops the creeping.

If those air vents are located on elbows above the boiler, they may not (but could) do anything. You said the pipes elbow over and into the wall, then down to the floor... so they are located at high spots in the system. Are the little caps on top loose? They should be in order to vent the air they capture (if the capture). They have a tendency to get crudded up too, and will leak water if they do. The solution is to close the cap and replace when the heating season is over. Most times though, they never get replaced. They can be used manually... loosen the cap, let the air out, close the cap again.

So for now, it sounds as though the pressure problem is fixed? and it seems to be running OK?

Now all you need to worry about is that durn condensation problem. I think the 'fix' for that is going to be to set up a mixing valve and another pump so as to limit the water temp to the tubing, and let the boiler run hotter... I think the install manual has examples of 'Low Temp' system piping.
 
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Old 05-26-10, 10:15 PM
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Alright! I think I'm finally done heating for the season. Trying to figure out the best thing to do now. Keep effin' around with this boiler or go a different route....like a Rinnai boiler or something...what do you think?
 
  #29  
Old 05-28-10, 08:32 AM
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Tough call to make from here! I'm not at all familiar with the Rinnai stuff... it sounds to me like your situation might be ideal for a mod-con.

Where are you at this point with the old boiler?

Let's see... you had the pressure problem, and from reading back the thread, it seems that has been corrected? You are running around 12 PSI cold, and maybe 15-18 hot?

We had talked about cleaning out the heat exchanger because the rollout switch was tripping out on ya... what's the current lowdown with that?

And then the condensation thing... how did things work out with opening the bypass valve? Did you monitor the boiler temps after doing that?

I guess we need a current synopsis of the situation...
 
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Old 05-28-10, 10:02 AM
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Just out of curiosity, what about the Rinnai is attractive to you? I'm unfamiliar with compact, wall-mounted boilers - but most, including Rinnai, come from Japan or similar areas where space is at a premium. And their layout doesn't seem to be particularly DIY friendly.

In Japan, maintenance and repair of residential appliances is a bit different than in the U.S. I'm told that if your toilet has a problem, you have to call Toto, who sends a uniformed factory service man to your house.
 
 

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