HC-125B questions

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Old 04-24-13, 08:58 PM
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HC-125B questions

I have a two-story 113 year old farmhouse in KS that has been retrofitted to baseboard heat, supplied by a HC-125B boiler, propane fired.
When we purchased the house 3 years ago, we had the boiler serviced by the only guy in a 100 mile radius we could find that had ever worked on a boiler, guess they arent that popular around here..he has since passed on..
After inspecting the system, he replaced the Aquastat and pressure gauge/temp gauge, and installed new drain valves for flushing the system, showed me how to do it, and installed two Honeywell zone valves, placing the first floor on one, the second floor on the other. He also installed an air purge on the return lines immediately before the circulation pump.
The boiler has worked fine until about a month ago, when the pressure relief valve started spewing every time the boiler was heating. I have flushed it numerous times, but it seems like its sucking air in somewhere and I have pipes knocking, and poor circulation. I replaced the pressure valve, thinking that might be the problem and replaced the air bleeders as well..
It didnt help.
I have read all I can find on this boiler, and now know that it is probably the expansion tank that is the culprit, it is horizontally mounted, and I intend to reconfigure it to a vertical mount. No water comes out the Schrader valve on the tank, but there is almost no air pressure in it either.

When I checked the Aquastat, it was set at 240, which seems very high to me, I have turned it down to 200, but should it be that high? The return pipes are luke-warm, and the "outflow" pipes will burn your hand..

What is the correct water pressure setting for the water supply coming into the boiler? It is currently at 11psi.. but as the boiler heats up, the pressure climbs to around 34, opening the pressure relief valve.

I think I need to replace the expansion tank, but dont know if there is a specific tank or size that I need to get.
No -one locally here seems to know much about these, and in fact, no local company wants to even come look at it. "We dont work on those". and we are 40 miles or so outside anyone's "area"...

I want to ensure it is set properly and safely, any suggestions will be greatly appreciated.

Thanks in advance!!
 
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Old 04-25-13, 04:23 AM
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You gonna have to drain the air cushion expansion tank.
There should never be any water in the top portion of these (ceiling mounted) tanks, as the relay on trapped air to create the room for expansion.
The (poorly placed) air purge, as long as it's what I am assuming is an automatic air vent or eliminator actually slowly removes trapped air from the tank, and it gets water logged.

Take pictures and post them of the near boiler pipework, close up and from an overall distance view
 
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Old 04-25-13, 07:42 AM
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TO is presuming that you have a 'conventional' old style compression tank, but I note in your description that you also mention a Schrader valve...

So I wonder if what you are saying is that you have the new style tank that looks like a gas grill propane tank, but it is mounted horizontally?

Yes, post some pics.
 
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Old 04-25-13, 05:46 PM
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thats what happens when posting prior to completion of first coffee.
It was the orientation of the tank that threw me off.

Disregard my post :-)
 
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Old 04-25-13, 09:00 PM
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Ok here are pics of my set-up, and YES I know I need to pipe the relief discharge down to the floor....
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Front veiw, Aquastat and gauge replaced in 2011, gauge verified that it is accurate on the water pressure using a test gauge this evening..

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Return lines with air-purge and bleeder. Expansion tank and releif valve

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Return lines and air-purge/bleeder, they go behind boiler and down to pump, as can be seen in next pic

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Water pressure regulator, circulation pump and expansion tank... hose is disconnected to ensure valve is closed after flushing system, then I place it back on so I dont loose it, or forget which one it goes on..

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Aquastat set on 220*f... I had turned it down, then decided not to "play" with it until I received some experienced advise..Water pressure is reading 17psi, system is off and cold..

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Over view of boiler, water on floor is still there from last time the relief valve vomited. Excuse the mess in the background..

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One of the two identical zone control valves that were installed in 2011

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Over view of the boiler and piping..The small section of garden hose attached to the feed line is where I attach the water hose when flushing the system.
The two large yellow valves isolate the pipes from the boiler itself when flushing..
Hope this helps.. I have an appraiser coming in two weeks to look at the house( we are refinancing) and I want to have this all up and good before then, even tho we are hopefully at the end of the heating season.
Considering replacing this whole mess with an electric heater before next year, but havent researched the feasibility of that yet.
 
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Old 04-26-13, 04:29 AM
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That is a weird expansion tank, looks almost like one for a well.
Regardless, you could remove it and try to add air to it thru the schrader.
If it hold great, if not replace it.

There is a plug in the bottom of the black air eliminator, that is where the tank should be connected.
Well, that is where it should be connected with out repiping the whole near boiler piping to pump away from the boiler as it should be. It will work as it is though, as long as the pump is on the suction side of the circulator.
 
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Old 04-26-13, 07:48 AM
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The small section of garden hose attached to the feed line is where I attach the water hose when flushing the system.
The system should not be routinely drained or flushed - every time you do that, you inject a harmful slug of air entrained or dissolved in the water. Only drain the system when required for maintenance, such as replacing a pump or component that can't be isolated.
 
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Old 04-26-13, 02:28 PM
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garden hose attached to the feed line is where I attach the water hose when flushing the system.
As Gil has said, this is NOT something that you need to be doing on a routine basis. Stop doing that if you are!

There is a plug in the bottom of the black air eliminator, that is where the tank should be connected.

Well, that is where it should be connected with out repiping the whole near boiler piping to pump away from the boiler as it should be.
Yes, I would remove the tank from it's present location and screw it into the bottom of the air separator.

More important though than pumping away from the boiler is pumping away from the point that the expansion tank is connected. If you move it to the bottom of the air sep, you will be doing just that.

You can probably pull the plug from the bottom of the separator and plug the existing tank connection point, it should be the same size , 1/2" .

Have you read both of these?

http://www.doityourself.com/forum/bo...sion-tank.html

http://www.doityourself.com/forum/bo...ure-gauge.html
 
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Old 04-26-13, 04:30 PM
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Have you read both of these?
Yes, I read both of those, great info. , That's how I realized my issue was probably with the tank rather than the relief valve.. and I have a pressure gauge that attaches to a garden hose, using that I verified that the gauge on the tank is correct.
I only flush the system at the beginning of the heating season,, I was simply explaining why the home-made stuff was hanging on the pipes.. dont loose track of it from one year to the next that way.

The expansion tank is in the correct place according to the installation manual, here is the diagram from the manual:
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But if I understand you correctly, it will work better hanging from the black air eliminator that is on the return lines? I will get a 1/2 plug for the pipe it is currently hanging from and move it .. can it hang or should I extend the pipes so it is supported on the floor?



I still have my original questions though:
1) is there a certain style, make, or type of tank I need to replace this one with? I am guessing a regular old well tank from Tractor Supply wont work?
2) what should the air pressure in the tank be? ( the same as the water pressure entering the boiler??)
3) What should the water pressure entering the boiler from the supply be set at? the manual gives NO info on this.. it is currently at 11PSI, but I have read several posts talking about 17-18 psi being correct..
4) is the Aquastat setting of 220*f too high? from what I have been reading on here, 180-190 is normal..
 
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Old 04-26-13, 04:59 PM
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OK ,I think I may have some of my answers now, but want to get input as I am sorta guessing

I can use a #30 Amtrol tank, and mount it vertically from the eliminator.

The tank should be pressurized to the pressure of the water entering the system when cold..

does that sound correct?
 

Last edited by ChrisReyn; 04-26-13 at 05:15 PM.
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Old 04-26-13, 05:17 PM
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only flush the system at the beginning of the heating season
Right... but you don't need to, and should not even do that. There is nothing at all to be gained from flushing the system. It won't work better. You will hasten problems by doing so. There's many reasons NOT to do it, and NO reasons TO do it.

But if I understand you correctly, it will work better hanging from the black air eliminator
Yes, correct.

Back in the 'olden days' when your system was installed, the modern theory of "pumping away" was not well known. If you google the term "pumping away" and ignore any porn sites, you can learn the 'why' behind the practice. Any articles you find by John Siegenthaler are golden... or Dan Holohan...

can it hang or should I extend the pipes so it is supported on the floor?
It can hang. You might want to run a piece of pipe strapping around the pipe and up to a floor joist just to support the weight when the tank does eventually fail and fill with water. You don't want the weight of the tank to be able to 'torque' the piping.

You need room on the bottom to access the air valve bi-annually. You know from reading those articles that these tanks will lose 1-2 PSI per year... they need to be 'topped up' every year or two.

1) is there a certain style, make, or type of tank I need to replace this one with? I am guessing a regular old well tank from Tractor Supply wont work?
A well tank isn't appropriate. It won't be designed for use with HOT water. You want a 'hydronic expansion tank'.

Expansion Tanks , Amtrol Expansion , Extrol Tanks , Therm-X-Trol Tanks , Boiler Expansion Tanks - PexSupply.com

Amtrol is not the only manufacturer... Bell & Gossett, Watts, and others are available.

2) what should the air pressure in the tank be? ( the same as the water pressure entering the boiler??)
When the boiler is COLD, there should be a minimum of 12 PSI in the system, and this minimum is the same pressure that the tank should be charged to.

3) What should the water pressure entering the boiler from the supply be set at? the manual gives NO info on this.. it is currently at 11PSI, but I have read several posts talking about 17-18 psi being correct..
The minimum pressure depends on the 'height' of the system. 12 PSI is adequate for a 2 story home. A 3 story home would require 17-18 PSI.

Physics is what determines this. You need about 0.432 PSI to raise water one foot. If your highest radiator is say 25 feet above the boiler, then you need 10.8 PSI to get the water to the top of the system. Because we always want the system to be under pressure, to this number we always add 3-4 PSI of additional pressure.

So, determine the height of the highest rad above the boiler and do the math.

4) is the Aquastat setting of 220*f too high? from what I have been reading on here, 180-190 is normal..
Yes, 220 is too high. 'Typical' high limit is set to 180F.

You said something in your first post that has me a tad concerned though...

The return pipes are luke-warm, and the "outflow" pipes will burn your hand..
The water returning to the boiler should only be about 20-30 cooler than the water leaving it. So, I want to ask a few questions about your system... and this also relates to the size of your expansion tank...

You said in your first post: "...retrofitted to baseboard heat..." and by this I presume you mean copper tubes with aluminum fins, yes? Or, are these CAST IRON baseboards? And by 'retrofitted', do you mean that it may have had cast iron standing radiators at one time?

Can you measure the footage of the heating elements on each zone and let us know what you've got?

If the water coming back to the boiler is that much cooler than the supply going out, it could indicate that there is an extreme amount of radiator on each zone... OR there is a 'lazy' flow through the system (water not moving fast enough). Because of this, the rooms at the end of the loop may be too cool for comfort, and may be why the temperature was turned up as high as it was.

About that expansion tank...

It's HUGE... look for a label on it and tell us what model that is. It appears to be a "90". It's very possible that you don't need one that large at all... the vast majority of systems that have fin-tube baseboard are perfectly fine with a "30" size tank.
 
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Old 04-26-13, 05:39 PM
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You said in your first post: "...retrofitted to baseboard heat..." and by this I presume you mean copper tubes with aluminum fins, yes? Or, are these CAST IRON baseboards? And by 'retrofitted', do you mean that it may have had cast iron standing radiators at one time?
I meant that the house was only heated by two fireplaces up until it was remodeled following a tornado in the early 70's.( yes no heater until then!).I have met the old lady who's family built this place ( by hand) back at the turn of the century, they homesteaded here... very interesting to learn the history of the place! ( they were still pumping drinking water out of the cistern until then also..)
They installed "slant fin" rads along the baseboards, 3/4" copper with alum fins. the first floor is about 1800 sqft, Counting 8 and 4 ft sections of rad, Id guess there is about 50 foot of radiator on the first floor..it is fed by two supplies, that basicaly split the zone into two runs, or loops
The second floor is 950 sqft and has about 40 foot of rad..all on one run or loop
The boiler's manufactor plate states it has an INPUT of 125000btu/hr, a heating capacity of 98000btu/hr and a"NET I.B. Rating of 85200btu/hr, and I have no idea what any of that means.LOL

And reading on here last night, I learned that they are installed in series, which explains why the bedroom is always cold..LOL
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Old 04-26-13, 05:51 PM
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About that expansion tank...

It's HUGE... look for a label on it and tell us what model that is. It appears to be a "90". It's very possible that you don't need one that large at all... the vast majority of systems that have fin-tube baseboard are perfectly fine with a "30" size tank.
No label or markings on it at all... its 16 inches long by 8 inch diameter..
 
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Old 04-27-13, 07:12 AM
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Cool home! I'm sure you realize that big tree probably poses a significant threat... would be a shame to lose the shade, but...........................

...Id guess there is about 50 foot of radiator on the first floor...
...The second floor is 950 sqft and has about 40 foot of rad...
Perfectly fine. No reason for the supply to be blazing, and the return to be lukewarm, other than a possible issue with inadequate flow.

What make/model pump is installed?

learned that they are installed in series, which explains why the bedroom is always cold..
Properly designed, a series system would not be responsible for cold rooms in and of itself.

Lazy flow... INSULATION issues... not enough baseboard installed to match the heat loss...

All these are possible reasons for cool rooms.

Older home, possibly little or no insulation. Any idea if the home was insulated after the renovation?

You have approximately 50K BTU of heat emitters (baseboards) installed. This could well be marginal for an older home of that size.

No label or markings on it at all... its 16 inches long by 8 inch diameter..
Hmmmm... looks bigger than that to me... you sure about the dimensions?

In any case though, based on what you've told us about the system and the amount of baseboard, I believe that you would almost certainly be able to use a #30 tank.
 
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Old 04-27-13, 07:50 AM
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Cool home! I'm sure you realize that big tree probably poses a significant threat... would be a shame to lose the shade, but..........
It was taken down this last summer., we almost hoped it would fall on the house, ( instant renovation)

What make/model pump is installed?
Not sure... again, there are no tags or labels... its red?lol

Older home, possibly little or no insulation. Any idea if the home was insulated after the renovation?
it was, but poorly, that is something we are slowly working on upgrading as time/money allows the original section of the house had horse-hair fiber, that settled into the first 3-4 foot of the walls, so it has been refilled with blown-in insulation, but with 2X4 walls, the R value is never gonna be great

Hmmmm... looks bigger than that to me... you sure about the dimensions?
I went down and measured it after you asked in that post, very certain..
16 inches by 8 inch diameter, 26 inch circumference

You have approximately 50K BTU of heat emitters (baseboards) installed. This could well be marginal for an older home of that size.
The original hardwood floors on the first floor were all removed when they remodeled and built the addition, leaving 1970's linoleum and carpeted rooms throughout the first floor.
We are going to replace that with a laminate, trying to restore the "look" of the original house( plus the linoleum is nasty!)
I am toying with the idea of replacing the baseboards with in-floor PEX when we do that...believe we would get better warmth through-out the house with that, and be able to have a heat supply in the kitchen, where there currently is none..but leave the baseboards on the second floor since I dont want to tear up the wood floors there.

I ordered a # 30 tank last night, so as soon as it arrives I will get that issue resolved and set teh water pressure and Aquastat correctly at that time

I cant thank you guys enough for all the great info and advice!!
 
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Old 04-27-13, 03:04 PM
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toying with the idea of replacing the baseboards with in-floor PEX when we do that...believe we would get better warmth through-out the house with that,
Don't be so certain of that! Heat output of radiant under-floor might (probably won't) be high enough to counter the heat LOSS from the home. As a general 'rule of thumb', you MIGHT be able to get 25 BTU per SQ FT from a properly designed floor heating system. Do your homework VERY carefully before undertaking a project like this.

If you are curious about your home's heat loss, you could play around with doing the calculations... this thread has a link to a software download that is easy to use:

http://www.doityourself.com/forum/bo...alculator.html

Should take you a couple hours... compare the amount of baseboard it says you need to that which is actually installed. You might get some insight as to why some rooms are cooler than they should be.

Not sure... again, there are no tags or labels... its red?lol
Post a close-up of the pump.
 
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Old 05-04-13, 09:43 AM
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Sorry for the long delay in responding, I've been busy dealing with a flooded basement
After two years of extreme drought, we had 4 days of heavy rain, which would be great, if apearantly my foudation settled and the drain tile is blocked.. its always something isnt it?
Been digging it up and clearing it..
But back to the boiler..
I got the new expansion tank installed, set the input pressure at 14psi, as per calculating the required pressure for our home per the math NJ supplied, and set the Aquastat at 190*f. Had no problems removing the old tank, although it was full of water.
The system seems to be working great now..
here is the new set up.
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I also ran a down pipe to the floor from the pressure relief valve

What make/model pump is installed?
Its a Bell-Glasco, NP28, found a partial tag on the end of it against the wall...

Oh, and the in-floor heating might still be a idea for the kitchen, which currently has no heat supply in it at all, and is on the north end of the house..gets cool.. all teh wall space is counters/cabinets and is no room for baseboard radiators, so anything would be more than whats currently in it.
 
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Old 05-04-13, 05:34 PM
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Good going!

Make sure to check the air charge in the tank at LEAST every two years. Not sure why you didn't put the optional valves on the tank connection when you change it? Forgot?

Yeah, if you've got no heat in the kitchen now, anything you add will be a plus. I assume that you have full access to the underside of the floor?

You do understand that you can not pump full hot temp water to the floor, yes? You will need a mixing valve and another pump to set it up properly.

Check out 'kickspace heaters'... they go under the cabinets.

Beacon Morris Kickspace Heaters , Kickspace Heaters , Beacon Morris Heaters - PexSupply.com

Might be an easier job?
 
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Old 05-05-13, 04:42 PM
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Question More issues!!


Well, today I get a call from the wife, "the house is cold".. its in teh 40's outside, thermostat set at 70, house temp 58 and falling..

Boiler is firing, all seems well, but it isnt circulating! What could have changed by moving the expansion tank location that would stop the pump from circulating water..

could have lowering the water pressure and Aquastat settings cause this?

I am 100% confident there are no air dams in the system, and when I place my ear against the pipes, I can hear a "hum" which I assume is coming from the pump.

This system has the pump "pushing" or pumping toward the boiler, and, now, away from the expansion tank... is it possible that the expanding water in the boiler is pushing against the pump towards the expansion tank, stopping the water flow?
I cant believe the pump has also failed at the same time the expansion tank has.. too coincidental.

It is a Bell-Gosset NRF-22 pump, which from reading online, I believe should be adequate for my home..

Any thoughts, suggestions or ideas?
should I set the Aquastat and water pressure back to where they were?
 
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Old 05-05-13, 05:20 PM
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I am 100% confident there are no air dams in the system,
Don't be so confident.

I am 99% confident that this is the trouble.

more later...
 
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Old 05-05-13, 05:30 PM
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ok, after making that last post, I set teh Aquastat back up to 210 and increased the water pressure by about 5 psi, working pressure( boiler hot) is now 25psi..

house has warmed up from 56 to 64 in the last 45 minutes..Im stumped..
 
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Old 05-05-13, 05:47 PM
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I don't recall if you've verified the accuracy of your pressure gauge or not... did you?

At least turn the aquastat back down... that is definitely not the problem.

Is the cap on the top of the air vent loose so air can vent?
 
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Old 05-05-13, 06:06 PM
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I don't recall if you've verified the accuracy of your pressure gauge or not... did you?
Yes, with a test gauge and it is accurate
Is the cap on the top of the air vent loose so air can vent?
Yes, it vented quite a bit of air when I opened the system back up after installing the expansion tank.. hissed like a tea kettle.. and its on just tight enough to keep the cap from falling off.
At least turn the aquastat back down... that is definitely not the problem.
Ok, what about the water pressure?.. from boiler to highest rad is roughly 18 foot..
You need about 0.432 PSI to raise water one foot. If your highest radiator is say 25 feet above the boiler, then you need 10.8 PSI to get the water to the top of the system. Because we always want the system to be under pressure, to this number we always add 3-4
So lets say its 20 foot.. 20X0.423= 8.46. add 4psi and I get (rounded off) 14psi, which is what I had set it at..
 
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Old 05-05-13, 07:21 PM
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what about the water pressure?
14 PSI should be more than enough for 18'.

You may still have some air in the system. It is possible that raising the pressure a tad 'squeezed' the bubbles and allowed them to move.

When you were NOT getting heat, before raising the pressure, did you feel the pipes? How far out from the boiler were they getting hot?

Please be reassured that moving the location of the expansion tank did NOT cause this. I'm sure that the others on here will concur.

Quotes from several posts back that still have me 'concerned' though, and could possibly have some bearing at this point:

You said something in your first post that has me a tad concerned though...

The return pipes are luke-warm, and the "outflow" pipes will burn your hand..
The water returning to the boiler should only be about 20-30 cooler than the water leaving it. So, I want to ask a few questions about your system... and this also relates to the size of your expansion tank...
When the heat IS working properly, are you still getting only a lukewarm return?
 
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Old 05-05-13, 07:42 PM
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No, I was wrong.. after you remarked on that, I borrowed a friends Pyrometer( it is a scan tool that measures temps, he uses it as a diesel mechanic) , the "out flow pipe from the boiler was 195, the return pipes measured 163.. quite hot actually, I should have made sure it had cycled a few times before I said it was lukewarm..

Before raising the water pressure, the water wasn't warming the pipes more than about 20 inches or so from the boiler, they were still cold to the touch at the yellow shut off valve( see earlier pics).. water wasn't moving anywhere through them...

I attached my hose to the bleed valve on the return lines, and let it slowly bleed water out, as the supply lines fed water back into the boiler( I know this is NOT a great idea, but it seemed like a way to dislodge any air blockage)*... this seemed to get the water flowing through the system again, and it began warming up the house..Its now up to 68*f in here and thats where the thermo is set at..
I could detect no air escaping from the bleeder as I did this, however it was slow enough that I may not have been able to notice.

I am beginning to wonder if the pump is too small, or 'weak" and in need of repair/replacement. If I had a hydrometer, Id measure the water flow from it, but as is, I have no way to tell.
New identical pump is $85+ shipping, but will be a waste of money if that isn't the issue.


*I DO NOT intend to make a habit of doing this.. was probably rather dangerous to the boiler ..and me..
 
  #26  
Old 05-06-13, 07:27 AM
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Before raising the water pressure, the water wasn't warming the pipes more than about 20 inches or so from the boiler, they were still cold to the touch at the yellow shut off valve( see earlier pics).. water wasn't moving anywhere through them...
That's a pretty clear indication that there was probably an air blockage... OR, remotely, and not very likely, a 'stuck' pump. In either case, it means no flow.

Remember that when you refill a system after servicing, using fresh water, you are adding dissolved O[sup]2[/sup] to the system. This O[sup]2[/sup] will for the most part remain in solution until the water is heated... several times...

So, what can happen is that at FIRST the system will be fine. You got all the bubbles out... but then the O[sup]2[/sup] that was in solution is driven off and begin to collect in the piping.

With the intermittent heating that is required at this time of year, it is conceivable that when the system shut down the air collected at the high points and blocked the flow.

As I mentioned, raising the pressure a bit would have compressed the bubble/blockage and allowed flow.

I attached my hose to the bleed valve on the return lines, and let it slowly bleed water out, as the supply lines fed water back into the boiler
No... not a great idea... large amounts of cold water into a hot boiler... CRACK!

Also, a 'slow bleed' won't do anything to move the air through the system. You need a velocity of at LEAST 2 feet per second to break up and move the air.

The proper way to 'purge' the air would be by shutting down the boiler and allowing it to cool to 100 or less. Then close the yellow valve next to the drain by the air scoop. Manually open the zone valves, one at a time and open the drain fully to allow as fast a flow as possible to push the air out.

I can't tell if your 'pressure reducing valve' has a 'fast fill' lever on it to bypass the regulator function. This would help get a fast flow through the system.

Problem is... again, the dissolved O[sup]2[/sup] in all that fresh water. At this time of year it's unlikely that you will be running the system enough to get rid of it all before shutting it down over the summer. The 'purging' is something that would best be done when you know that you will be running the system for a while to drive out all of the air.

I am beginning to wonder if the pump is too small, or 'weak" and in need of repair/replacement
Highly unlikely. The NRF 22 is more than capable of pumping your system.
 
  #27  
Old 05-06-13, 07:31 AM
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borrowed a friends Pyrometer
Something about 'non-contact' types of measuring devices...

They are prone to inaccuracy. It has nothing to do with how cheap or expensive the instrument is. It has to do with a property of materials known as 'emissivity'.

Depending on the emissivity of the material, the reading could be off quite far.

Measuring copper pipe... even if it is old, dull, and oxidized, will not give an accurate measurement. If you measure the SAME material on both supply and return, the DIFFERENCE may be close, if the actual magnitutude is not.

Cast iron is fairly accurate... experiment a bit and not the difference of the copper going into your air scoop, and of the air scoop itself and I think you'll get a feel for this...
 
  #28  
Old 05-11-13, 01:57 PM
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Thanks for all the help NJ, its working fine , been distracted from teh boiler issues by a flooded basement issue, looks like I am replacing drain tiles next..
its always something..

http://www.doityourself.com/forum/ba...#ixzz3ODEZkc8A
 
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