Most radiators not hot

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Old 09-21-14, 10:03 PM
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Exclamation Most radiators not hot

Hi there, I have a problem with my boiler hot water heating system, i.e., when it is turned on, most of the radiators (17 out of 20) are not hot / heating. It is an old two story house with average 6-7 radiators on each floor. The only working radiators are on the main floor. It stopped working properly in the mid of last winter, a historically cold one. But I ddn't fix it in the past summer due to high temperature. Now the winter is coming again, I just started working on it. Now it is shut off (cold), and the pressure gauge shows about 23 PSI. Based on NJ Trooper's Sticky as to "How to verify a boiler pressure gauge", I bought a pressure gauge and some adaptors. However, I couldn't even find the right drain connector. Instead, it is a drain valve with a long plastc pipe.

Besides, when I tried also to check the expansion tank following Trooper's sticky, I can't even find the air valve to connect the pressure gauge either, but a valve with red bar (on/off). So how should I proceed? BTW, it is a RAYTHERM boiler and a WATTS regulator brand expansion tank (made in Italy).

Thirdly, there is a huge tank under the ceiling connected to inlet(cold) side of the system with a simple ball valve but I can't turn it. I suspect it is still in use or why it is there.

Lastly, when is turned on, the circulator pump makes significant noise, but no clue what's going on.

Do I still need to start with pressure check and then others? But how if yes (the connector doesn't fit my gauge, or do I need to make a new adaptor)?

Any advice would be appreciated! Winter is coming, I got to fix it ASAP.

Thank you!
 
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Old 09-22-14, 05:26 AM
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Hello and welcome to the forums...

For what its worth, here is a link to the raypak website. They are very good boilers.

Raypak Residential Hydronic - RaythermŽ Hydronic Boiler, 0042-0180

What we need is the exact model #


It may be air in the lines and you may need to bleed... It could be a failed circulator, or even a zone valve.. Last if the gauge is off it can be PSI related..


It would be best if you can take several pictures of the boiler from several angles so we can see the controls and such..

Let us know...
 
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Old 09-22-14, 06:41 AM
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Hi Lawrosa,

Thanks a lot for your quick response!

I am new in this area. But based on some reading of threads of similar problems, I might need to start from the pressure check. So I got to think of some way to measure it with my new gauge.

Following advice from other site, I did a quick simple check on the expansion tank by hitting it with a small metal piece at top and bottom part of the tank, respectively. It sounded differently and my sense of feel is that the tank is ok.

Yes I have taken some photos of the system, and will post it here later today.

Thanks again.
-York
 
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Old 09-22-14, 08:45 AM
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Following advice from other site, I did a quick simple check on the expansion tank by hitting it with a small metal piece at top and bottom part of the tank, respectively. It sounded differently and my sense of feel is that the tank is ok.
Hi York,

It has been proven time and time again that the 'tap test' of an expansion tank is absolutely NOT a valid test. It is just plain nonsense that someone can determine the correct air charge in an expansion tank by tapping on it.
 
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Old 09-22-14, 12:26 PM
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Hi Trooper,

Thanks for your correction! So I do need to check the tank by attaching a gauge. But strangely enough, I can't even find the air valve. I will post photos later today.

Also, before I can attach my new gauge, I can first test the existing pressure gauge by opening the drain valve in cold state and closed system filling valve (hot side). If the gauge works, the needle should move down to lower reading /pressure. But I guess I can't drain the system completely as there will be air vacuum generated on the top radiators. Does this make sense?

BTW, again I am new in this area. To teach myself, I was trying to find a typical text book on this or something like Boiler heating system 101 for basic knowledge. Where can I get this or can I find it here in this forum/site?

Appreciate your time.

-York
 
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Old 09-22-14, 12:40 PM
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Hi York,

Yes photos will help a great deal...

Just because the needle might move when you drop the pressure doesn't mean it's accurate... so that's pretty much a 'non-test' also.

I don't know about "Boilers 101", but just reading back messages here will help a lot... try out the 'search' function and see if you can find stuff that helps.
 
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Old 09-22-14, 12:43 PM
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Originally Posted by NJ Trooper View Post
Hi York,

It has been proven time and time again that the 'tap test' of an expansion tank is absolutely NOT a valid test. It is just plain nonsense that someone can determine the correct air charge in an expansion tank by tapping on it.
The tap test just determines whether or not the diaphragm is still intact. It has nothing to do with the charge.
I would purge the loop then check the radiators for bleeders. Lots of older systems are a venturi loop. That means it's one main loop with branches off to each radiator. Most vents you can bleed with a screw driver. Open them up until you get a solid stream of water.
 
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Old 09-22-14, 01:02 PM
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In my opinion, I doubt if anyone could tell by a tap test if the diaphragm is intact or not...

Besides, we don't have enough information yet to even know what kind of a tank it is... for all we know it might not even be a diaphragm type tank.

There is no point in purging or bleeding anything until we know there is enough pressure in the system.
 
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Old 09-22-14, 01:11 PM
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Trooper if you have an extrol on your system go flick the top and bottom. You will hear the difference. If there's no difference in sound it's full of water. Too easy.
 
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Old 09-22-14, 02:28 PM
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Time and again ppl have come here and said they've done the tap test and said:

"My tank is fine, I tapped it and it's good"

Yet they continue to have trouble.

When they are finally convinced to do it right and actually check the pressure, whatta ya know?

Imagine that! WATER out the schrader valve... or less than 5 PSI in the tank.

Bottom line is that maybe YOU can tap a tank and miraculously know the internal condition, but it is HIGHLY unlikely that someone who admittedly is a newbie to this will know what to listen for and what it might mean.

The 'tap test' is inconclusive. Period. No more argument.
 
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Old 09-22-14, 09:50 PM
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Most radiators not hot - system photos

Hello Lawrosa / Trooper / dburr9,

Thanks a lot for your time and input! Attached please find the photos of my system and components. Now the specific questions are -

1) How can I make an adaptor to connect my newly bought pressure gauge to the system?

2) How can I measure the air pressure inside the expansion tank while there is no air valve with the tank?

3) If I shut off the water feeding valve and open slowly the drain valve, how much psi should I expect for the existing pressure gauge (assume it works)? I figure out it should be 0 psi or about 15 absolute psi (ambient pressure). Does it make sense?

Again, I greatly appreciate your help, and believe that I can fix the problem with your help and my knowledge of thermo-fluid

Thank you,

-York
 
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Old 09-22-14, 10:10 PM
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Here are the photos

1a) system - view-a
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1b) system - view-b
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2) expansion tank with valve
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3) expansion tank
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4) circulation pump
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5) P-T gauge
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6) pressure relief valve
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7) huge tank under ceiling (connected to cold/inlet side with valve, not sure if it is still in use)
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8) water feeding/check valve
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9) drain valve with pipe
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Old 09-22-14, 10:14 PM
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Two(2) more photos and captions

10) RAYTHERM Boiler
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11) Electric parts
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Old 09-22-14, 10:22 PM
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Just skimmed thru your problem quickly. If your can't find the tire valve on the x-tank it's sometimes hides under a plastic disk on the bottom that you spin off. Hope this helps.
 
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Old 09-22-14, 10:32 PM
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Hi guyold,

I saw nothing/no where to hide, but I can double check tomorrow.

BTW, the gauge readings are under cold/shut off condition.

Thanks for your quick input.

-York
 
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Old 09-22-14, 11:01 PM
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There might be a plastic nut covering the valve.Might be blue. Sorry it's late.
 
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Old 09-23-14, 04:06 AM
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The expansion tank will not cause your no heat issues.. ( The valve is on the bottom of the tank)

You have several issues there, but none are related to no heat..

As I said you need a gauge to test if you indeed have 23 psi as shown on the factory gauge. That is too high anyway if it is indeed accurate..

IMO best you can do is too remove the gauge thats there and replace.

With that said the work that needs to be done is simple for a plumber to perform but may be a daunting task for the homeowner..

1. Replace gauge. To do this both large valves need to be closed here at in and out piping. Still a large amount of water will come out so a bucket is needed. If valves don't hold then water feed needs to to be closed and boiler drained somewhat.

[ATTACH=CONFIG]38770[/ATTACH]


2. Close this red valve at exp tank and remove tank. Then est tank psi. Adjust to 12-15 psi and reinstall.. You may need to replace... IMO also that exp tank may be too small.

[ATTACH=CONFIG]38771[/ATTACH]


3. Both air vents need to be replaced. They are the small brass canisters. One a top the air separator as shown in pic above. Its on top of the exp tank. Ans the other is ontop the pipe if you follow the circulator. Its seen in the first pic above.


4. This tank in ceiling... Any pipes too it must be closed. This tank is no longer needed since they added the other smaller type exp tank. Make sure and valve to this tank is closed.You said there is a valve to it and its open? Take pic of this valve and pipes please.

[ATTACH=CONFIG]38772[/ATTACH]


5. After all repairs are made there the fill valve then needs to be checked to make sure boiler fills to 12-15 psi. If not then the fill valve needs to be replaced..

[ATTACH=CONFIG]38773[/ATTACH]

6. Then when system is started the circ will need to be tested. You said it makes noise? I suspect this is your issues. Your near rads are probably heating by gravity...

[ATTACH=CONFIG]38774[/ATTACH]

7. Then after all is fixed boiler needs to fire to limit to make sure aquastat is functioning....

8. All rads bled to make sure air is removed and system/rads heat properly...
 
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Old 09-23-14, 04:53 AM
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most radiatiors not heating

What type of radiator are in the rooms? If they are large cast iron the expansion is defiantly too small, the large tank is the original expansion tank and must still be connected or the pressure relief valve would be leaking due to high pressure.
 
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Old 09-23-14, 10:49 AM
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Hi Saves,

Yes they are old large cast iron radiators. The expansion tank may be too small for the total 20 radiators, but I have no experience or knowledge on this except for the fact that the expansion tank has already been there for years. At least, for now, it might not be the root cause of my problem. So I think it will be of low priority at the moment. Thanks a lot, anyway!


Hi Lawrosa,

I appreciate your prompt comments and input as to how I should proceed next! I will follow your suggestion and probably start with the gauge replacement, as it is a very important part and could be misleading, plus, it is relatively cheaper. After that, if it still does not work, I may try the pump.

The 12-15psi at cold is basically caused gravity of the water height, right? The higher the house (where top radiator sits), the higher this psi. That's my understanding. Please correct me if I am wrong.

BTW, I think I have mixed up the pressure relief valves and air vents. But where is the pressure relief valve usually positioned?

Thank you all again!

-York
 
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Old 09-24-14, 09:32 AM
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The 12-15psi at cold is basically caused gravity of the water height, right? The higher the house (where top radiator sits), the higher this psi. That's my understanding. Please correct me if I am wrong.
Not completely wrong... it is true that PART of the pressure you see on the gauge comes from the column of water above, but pressure is ADDED to the system so that even the very tip top of the system is at least 3-4 PSI above GAUGE pressure.
 
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Old 09-24-14, 05:51 PM
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Hi Trooper,

I thought the 12-15psi at cold is absolute pressure so the gauge reading should be close to zero(0) IF there is no air at all on the top. But in reality, there might be no absolute vacuum on the top because if absolute vacuum exists the water may vaporize and generate some water gas and a few PSI pressure, which (not sure) may be the 3-4psi at gauge you mentioned, or does it make any sense to you?

Anyway, I will follow your pressure check method to measure the system pressure once I get my new gauge. Unfortunately, it doesn't seem that easy to find the right one, as many gauges have bigger PSI range than I need (50-60psi ideally). Any idea where to find the right one?

I got to race with time and fix it before winter comes

Thanks again for your time and help!

-York
 
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Old 09-24-14, 06:08 PM
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Go to the home store.

Boiler Temperature and Pressure Gauge-WR1711016 at The Home Depot

Also you may need a brass bushing to reduce the size as your gauge may have a bigger threaded end...
 
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Old 09-24-14, 07:43 PM
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thought the 12-15psi at cold is absolute pressure
No, it's gauge pressure.

might be no absolute vacuum on the top because if absolute vacuum exists the water may vaporize
Yes, vacuum at the top of the system is what needs to be avoided... the 'extra' 3-4 PSI pressure is to prevent a vacuum from forming and allowing bubbles to form, or for any existing air bubbles to get very large and block flow... or worse yet, in some cases if the water is hot enough it can flash to steam.

Gauge pressure at the boiler should be 12 PSI , OR ,

0.432 times (height of system from bottom to top) PLUS 3-4 PSI.

Whichever is greater.
 
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Old 09-24-14, 08:16 PM
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Hi Trooper,

You are absolutely right when the system is closed!

I was assuming the scenario with the drain valve being open, but I didn't say it explicitly. The reason I asked about that case/question is that I was trying to check the gauge simply by opening the drain valve and see if the pressure needle drops to whatever reading it is supposed to. Of course, in this case, the feed valve is shut off, and I was guessing the water will drain a little bit in the beginning and then stop due to vacuum on top. So the gauge reading may be zero or a few psi higher than 0 due to water vapor generated on top.

Now that I plan to replace the gauge following Lawrosa's suggestion, I don't need to consider this. But your clarification is still helpful for sure. I am still learning.

Lawrosa, I just checked my local homedepot, there is nothing in stock. I might have to go to a local plumbing store for a quick result.

Thank you all!

-York
 
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Old 09-25-14, 02:32 PM
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Old 09-26-14, 03:43 AM
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Thanks Trooper,

I found one here in a local store and will go pick up today.

-York
 
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Old 09-27-14, 08:44 PM
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update -

I did a test on the existing pressure gauge before I replace it. The process and questions are as follows.

1) Shut off feed valve, and then drained the boiler and meanwhile watched the gauge pressure;

2) The reading dropped as more water was drained, and it dropped from original 23 PSI down to below 10 PSI after about 10 gallons of water were drained, see photos below. The water color changed from dark dirty to almost clear and clean;

3) opened the feed valve, expecting to hear/see water flow in and gauge pressure go up to at least 12 PSI, but nothing happened;

4) observed the feed valve and noticed that the stem never went up or down when I opened or closed the valve. Is it normal or is it a special valve that the stem doesn't move up and down when turned?

5) furthermore, I tried to open the upstream valves of the feed valve just in case they are shut off. However, none of them can be rotated/turned. These two valves have a screw at center of valve stem, which might be a kind of special valve?

Any advice would be appreciated!

Lawrosa, I took a photo for the connection valve between the huge tank and the cold water side, see below.

Thanks in advance!


The new reading of gauge pressure dropped from 23 to below 10 PSI
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The feed valve stem never move (up or down) when turned (open or close)
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Name:  feeding valve2 (640x480).jpg
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Two(2) special valves upstream the feed valve, but can't rotate them. Note, these valves have a screw at center. Supposed to be open but why gauge pressure doesn't go up???
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Name:  upstream valve2 (640x480).jpg
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huge tank connected to cold side of boiler with a regular ball valve (can't turn the valve though, so it may be shut off)
Name:  huge tank and valve (640x480) (640x480).jpg
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Old 09-30-14, 11:47 AM
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gauge pressure increased slowly to over 20 PSI

Before I replace the pressure temperature gauge, I did a test, i.e., drain the boiler/system with water feed valve shut off. The gauge reading dropped below 10 PSI, but I didn't see what is supposed to happen when I opened the water feed valve, namely the pressure reduced/regulator valve didn't open to fill the system. So I manually open it by pushing in the stem. Then the gauge pressure climbed to about 12PSI, and styed there without further increase ( I watched for at least an hour). However, the next day (after 24 hours) when I went to work on it, the gauge pressure was already a bit over 20 PSI. What happened??? My questions are -

1) Is it possible that the pressure reducer valve is leaking?
2) should I try drop its spring pre-load by turning the screw counter-clockwise somehow in order to reduce the set pressure?
3) If the valve is leaking, do I have to replace it or can it be repairable?
4) It means that the original gauge pressure of about 23 PSI at cold could be the result of leaking pressure regulator valve and the system might be working on a higher than usual pressure. So could it (high pressure) cause the pump noise in operation?

Any such experience or advice would be appreciated.

Thanks.
 
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Old 09-30-14, 03:32 PM
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1) Is it possible that the pressure reducer valve is leaking?
Yes it is. It's a common failure mode. When they fail they either won't feed water, or they will leak through, slowly, internally.

2) should I try drop its spring pre-load by turning the screw counter-clockwise somehow in order to reduce the set pressure?
No, in my opinion, it's pointless, even though it's the first thing that you will hear from a LOT of people. They just don't go out of calibration all by themselves. The either plug or leak.

It IS possible that someone has messed with it in the past though... so there is no definite clear cut answer to this. I suppose it can't hurt to try at this point, you might get lucky.

3) If the valve is leaking, do I have to replace it or can it be repairable?
Replace it. If you can even find one, the kit is going to cost nearly as much as a new valve.

4) It means that the original gauge pressure of about 23 PSI at cold could be the result of leaking pressure regulator valve and the system might be working on a higher than usual pressure. So could it (high pressure) cause the pump noise in operation?
If the gauge only went to 10 PSI when it should have been ZERO, all other bets are off. The gauge accuracy is completely unknown. It COULD have been correct, but it also could have NOT. No way to know.

No, pressure won't cause pump noise.

What does the pump noise sound like? Can you describe it?
 
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Old 09-30-14, 03:47 PM
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KKM, several posts back, Mike instructed the order of things to do and the repairs that need to be made on your system. Have you done all of these?

I don't know if anyone has advised that the white insulation wrapping on your pipes is probably ASBESTOS. Don't disturb it and cause the fibers to become airborne. You may wish to consult with asbestos removal specialists and have that stuff taken out of your home.
 
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Old 10-01-14, 09:56 AM
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Hi Trooper, thanks a lot for coming back and advise. I really appreciate it!

First, I heard about that material and will deal with it later;

Secondly, yes I do have Mike's suggestion of procedure in mind. But to start with the gauge issue(possibly), I did the test as I mentioned in my posts, i.e., drained the boiler down to below 10 PSI and see if the gauge is responsive. Yes, its reading dropped, but on the other hand, when the water feed valve is open, the system wasn't fed immediately. Instead, I manually fed it to 12 PSI, but the next day it went up to 20PSI without doing anything, which is found to be the pressure reducing/regulator valve problem, as you just confirmed.

Anyway, I am steadily working towards that direction as Mike pointed out, and keep updating here.

One last question is, why the latest reading is 20PSI instead of 23PSI of original reading at cold? I guess there are 2 possibilities, 1) the previous manual feeding (by previous owner or technician) was that high (23PSI, no good though), and 2) the existing pressure reducing valve has that actual set point (20PSI).

Thanks again!
 
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Old 10-01-14, 11:47 AM
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One last question is, why the latest reading is 20PSI instead of 23PSI of original reading at cold? I guess there are 2 possibilities, 1) the previous manual feeding (by previous owner or technician) was that high (23PSI, no good though), and 2) the existing pressure reducing valve has that actual set point (20PSI).
Faulty gauge or faulty PRV... Or both.... Yes someone could have set the prv to a higher pressure by fiddling with it... Or it could be 12 psi and the gauge is off..

Start with a new gauge then go from there...
 
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Old 10-04-14, 12:14 AM
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progress with further questions

Hi Mike /Trooper,

I did following today -

1) noticed the gauge pressure at cold went from 14 up to 25 PSI after waiting for one day (I adjusted PRV screw in and then out back to original position and noticed the reading was 14PSI);

2) removed the old gauge and left the opening there without installing the new one yet;

3) BTW, checked the expansion tank with a bike pump, no reading initially on bike's gauge, nor water came out of the air valve stem;

4) charged the tank but the gauge reading moved just a little bit up, but saw water coming out the opening left by the old pressure gauge, which I believe is due to air pressure increase despite no obvious move of the needle on the bike pressure gauge. Do you think the tank is ok and just need some charging?

5) the tank label says the pre-set pressure is 12PSI. my question is a) is this gauge pressure or absolute pressure?, and b) under what condition, with system water column or not (this will be a big difference, as the water column would be about 15 PSI). So I think it is with no water exerted on it, i.e., the pre-set before installation. Please confirm.

BTW, is the PSI usually means gauge pressure instead of absolute pressure in the convention of boiler heating system?

Thanks a lot!
 
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Old 10-04-14, 12:18 AM
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Just forgot 1 question, i.e.

If the PRV is leaking, why does the gauge reading stopped at 25 PSI instead of water supply pressure (>50PSI)?

Thanks.
 
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Old 10-04-14, 01:14 AM
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It will take quite a bit of pumping from a bicycle tire pump to raise the pressure in the bladder of the expansion tank, at least three times as much (probably more) than pumping up the bicycle tire from flat. During that time the bladder will be expanding and that will cause the water to flow out of the open gauge port.

The PRV MAY be sealing once the pressure in the boiler gets high enough. The PRV is only about $30 (give or take) so replacing that old one is a good idea. At the same time you should replace the safety valve on the boiler every five years no matter what.

The valve you mention regarding the old expansion tank in the ceiling (this picture) [ATTACH=CONFIG]39352[/ATTACH]
is NOT a ball valve but a globe valve. Ideally it should be removed and the pipe plugged but you do not want to be working that close to that crumbling asbestos-containing insulation so instead break the union downstream (closer to the tank) and remove the piping back to the valve and insert a plug.
 
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Old 10-04-14, 11:33 AM
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I strongly doubt that the diaphragm type tank that is on the system is large enough.

The tank in the ceiling may in fact still be 'active', but there's little doubt that it's probably waterlogged.

I don't think I would suggest removal or disconnection at this time.

4) charged the tank but the gauge reading moved just a little bit up, but saw water coming out the opening left by the old pressure gauge, which I believe is due to air pressure increase despite no obvious move of the needle on the bike pressure gauge. Do you think the tank is ok and just need some charging?
If there was no reading on the gauge on the air side of the tank, it was full of water.

You need to keep pumping until you have 12 PSI on the air side.

YES, as you pump up the tank you will force the water out of the tank and it will come out the open gauge port on the boiler. You are pushing the water out of the tank and into the boiler, it has to go somewhere.

If the tank holds it's air charge, it may be OK...

5) the tank label says the pre-set pressure is 12PSI. my question is a) is this gauge pressure or absolute pressure?, and b) under what condition, with system water column or not (this will be a big difference, as the water column would be about 15 PSI). So I think it is with no water exerted on it, i.e., the pre-set before installation. Please confirm.
GAUGE pressure, that's all we care about.

Yes, the only way that one can properly adjust the air charge in a diaphragm expansion tank is if the water side is at ATMOSPHERIC pressure, or ZERO PSIG.
 
  #37  
Old 10-04-14, 10:15 PM
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record of the issue

Hello Trooper / Mike,

I have worked a lot on my boiler system today, although the problem is even a little worse than before -

1) I successfully charged the expansion tank to 12PSI with a bike pump and a separate pressure gauge;

2) installed the new pressure/temperature gauge;

3) fed the system and bleed the air for all radiators (about 20, a lot of work, up and down in the 2 story 4 level house including basement and attic;

4) turned the PRV one round clockwise (increasing the system pressure) and fixed the pressure at about 16-17PSI. The reason I chose a little higher than 12-15 PSI is that when I bleed the air on the top level, there was not much water or slow water flowing out of radiators, meaning the pressure is not high enough.

5) eventually I tested the system, first by turning on the pump power supply but leave the thermostat off. Strange thing is that whenever I turn on the power supply, the pump always starts to work (not supposed to though). This is my first question today.

6) later, when I switched on the thermostat and set the temperature to high enough say 30 deg C in order to start the system. However, the problem is not only there, but also even worse. Except for the pump noise, the system pressure started to become unstable shortly and seemed to have explosion sound - very scaring. Meanwhile, the temperature rose very fast and it started from 22degC and climbed up to over 100 degC in just a minute or so. I guess the flow is too slow so the water may have reached vapor point (100degC) locally and became water steam, and then back to liquid shortly when reached cold water, so the pressure changed dramatically up and down in the system and made the scaring noise or explosion sound. I checked all the valves along the pipes and at radiators to make sure they are all open. So the flow is blocked somewhere is not likely. So I suspect the pump was working normally. Its running noise (louder than what I have in another house) also makes me believe it is quite possible - pump is not working normally. Another observation seems also to confirm my assumption, i.e., the pipes not far from the hot water outlet (or after the pressure/temperature gauge, note: the temperature reading already reached over 100degC at gauge location) didn't seem to be hot at all when I touched it, meaning very slow flow.

Besides, is it possible to have too much air inside the boiler which was induced by installation of gauge? but I already bleed the air from all RADs, can air hide in boiler?

Attached is the short video recorded of the issue, I believe it will help people understand what I am saying and help me solve the issue. I am thinking to replace the pump. But before I do it, I'd like to get your thoughts/advice.

Again, I really appreciate your time and help!!! I really need to fix the issue as the winter seems to be at the corner now.

Thank you all!
 
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Old 10-04-14, 11:00 PM
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record of the issue - a short video

http://youtu.be/AJj4wrFDZ8E The base noise is from circulation pump and others from inside the boiler.

Top is pressure and the bottom temperature (note, it reached 100 degC in a minute or so).

If you had same experience / issue before, please help identify the root cause.

I am tending to replace the pump. Trapped air inside boiler might be another possibility but how to get rid of it if it doesn't move up?

Appreciate your help!
 

Last edited by kkmdiy; 10-04-14 at 11:18 PM.
  #39  
Old 10-05-14, 02:54 AM
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thats not right...

Did you change the air vents as I said to? You sure all valves are open?

[ATTACH=CONFIG]39418[/ATTACH]

[ATTACH=CONFIG]39419[/ATTACH]
 
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Old 10-05-14, 07:18 AM
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Hello Mike,

Thanks a lot for prompt advice!

Yes, I could replace air vents too, but I tested the vents and found they still seem to work fine (bleed air manually). If you think that's the reason, I can replace them ASAP.

On the other hand, do you think the pump is a big suspect? As said earlier, I tend to believe that's the major cause. If there was air trapped in boiler, when I turned on pump without firing (thermostat off), the air should have moved up and the boiler shouldn't have been over heated when firing. That's why I suspect the pump more.

Your thoughts?

Thanks again!!
 
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