Leaky Pressure Relief Valve PSI 30 on slant fins

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  #1  
Old 09-30-08, 10:21 AM
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Leaky Pressure Relief Valve PSI 30 on slant fins

hi
please advice me .I have a slant fins boiler S 90 DP.
The pressure relief valve PSI 30 was leaking drop by drop.
I replaced the valve with identical new valve 30 psi.
On starting the system the valve has stopped leaking
but the pressure gauge on boiler was going beyond 30 psi with in few minutes .
I then stopped the system .however the heating was ok.
Can you suggest, if It is safe to run the system and how I can reduce the pressure in the boiler ?
regards
Rajan
 
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Old 09-30-08, 03:06 PM
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Rajan, your problem is most likely due to having a problem with your expansion tank. There are two types of tanks, and the procedure to maintain and check them out is different.

One type is a "Bladder" style, and that looks like a gas grille propane tank. It usually will be found hanging from the pipes around the boiler.

The second type is a "conventional" style, and is a large tank, about 12-16" in diameter, and perhaps 36" long. It will be found at the ceiling of the boiler room, held in place with metal straps.

Please set up a photo hosting site at www.photobucket.com (free) or a similar site, and upload pictures of your boiler and all the pipes and valves and tanks that are near it. Come back here and post a link to your album and we can tell you what to do from there.
 
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Old 10-01-08, 08:22 AM
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Please advice Trooper

Hi NJ Trooper,
Thanks for your prompt response.
I have uploaded some photos for your reference.
http://s374.photobucket.com/albums/oo182/rajan1011/
please let me know if you need more detailed pictures/Close Ups.
Today again, I ran the system ,in both the floors .adjusting the termostate reading at 80 F.
results.
1 As soon as the 30 psi is reached in slant boiler gauge the relive valves starts dripping .
2.The system cuts off around the same pressure but the temprature keeps on climbing to 200 F.
3 before its cuts off ,the dripping from the relive valve increases to a steady flow with steam comming out.
4 Relive valve is new and replaced with ,what is recommended by the manufacture.
please advise with regards
Rajan
 
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Old 10-01-08, 09:44 AM
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Just let a bit of water out to reduce pressure... not much at all.

If your pressure is normally much less than 30 psi it is your expansion tank. I'd consider hanging it although some people firmly believe that are fine standing. I think it allows you to have air on both sides of the internal rubber membrane in the expansion tank when it stands up like that. and that allows the membrane to dry out and tear. You might want to rotate the new one around and down and also you should add a small tee, a ball valve and a hose bib and it'll be easier to replace. Add the ball valve after the tee where it ties into the rest of the system and then pipe the tee. Hang the tank down and have a hose bib you that you can release the pressure from in the tank if you ever need to service the tank.

Let the boiler water cool before changing the tank. Make sure the make-up water is shut off and don't drain down any more than you absolutely must.
 
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Old 10-01-08, 03:08 PM
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I still believe that your expansion tank is the fault.

Do you have an accurate tire pressure gauge for your car ?

Turn off the boiler and allow it to cool to 100F.

I can't see in the pictures... too dark and grainy for my old eyes, but there must be a valve to turn off the water supply to your boiler.

CLOSE that valve.

Lift the handle on the pressure relief valve and drop the pressure on the gauge on the boiler down to zero.

Remove the little black plastic cap on the top of the expansion tank and use the tire pressure gauge to measure the pressure in the tank.

It will be very low, like a flat tire.

You will need a small air compressor, or if you feel very strong, you can use a hand pump to add air to that fitting on the top of the tank until you have 12 PSI in that tank.

Check to see that the gauge on the boiler is still ZERO PSI. If it is not, let more water out of the relief valve and drop that pressure to ZERO PSI again.

Check the tire fitting on the top of the tank with your tire gauge again. If it is less than 12 PSI, add more air.

Repeat the three steps above until you have 12 PSI of air in the top of the tank, and zero PSI in the boiler.

OPEN the valve that will allow water to fill the boiler.

Check the gauge on the boiler. It should be 12-15 PSI.

Turn the boiler on and heat it up, the pressure on the boiler should only increase 5-8 PSI and the relief valve should not open anymore.

If this does not work, it means that the expansion tank has become defective and must be replaced.
 
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Old 10-01-08, 05:03 PM
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Thanks

Hi NJ Trooper,
My congratulations ,I am impressed with your deep knowledge on the subject.
I exactly followed your instructions and its working the PSI is around 23-25, I have few questions to understand >
1. it seems the system is cutting off quickly then before .earlier it use to take some time to reach that particuler temprature now the system is shutting off early.
however I tested at around 80 F .but the leakage is totally stopped .Do you think I need to do something to set it right?
2. kindly explain me how techanically this was achived ? I mean when i filled the air and discharged the water .Where this excess water came from and why we discahrged it ?
looking forward to your advice.
regards
Rajan
 
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Old 10-02-08, 04:06 PM
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pressure in the expension tank

Hi NJ Tropper,
How often should I check the air pressure in the expension tank.?
regards
Rajan
 
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Old 10-02-08, 04:51 PM
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Hello Rajan, I'm glad that your system is better, but I'm not sure that it will be 100% repaired yet.

Here is some technical info for you:

The expansion tank has a rubber membrane, or 'bladder' installed inside of it. One one side of this bladder there is AIR, and on the other side there is boiler water.

When water is heated from 70F to 180F the volume of this water expands approximately 4%. This expansion of water requires that there is somewhere for it to expand into.

You can not compress water. You CAN compress air.

By placing a 'bubble' of air inside that tank, you have given the water room to expand.

If there is NO AIR in the tank, there is nowhere for the water to expand and you will see a large pressure increase in the system.

The membrane in that tank is not 'perfect'. Air WILL leak through it at a very slow rate. I'm sure you have seen childrens baloons slowly lose air and deflate ? This occurs inside that tank also. It is said that those tanks may lose air charge at the rate of approximately 1 PSI per year. When you lose air, water will push in to take it's place. When you lose enough of that air, the tank becomes what we call 'waterlogged' and will not do it's job of allowing expansion of the heated water.

It can also happen that the bladder in the tank develops a leak or a tear. In this case, the tank must be replaced, because the air that is in the tank will dissolve in the water and accumulate at the high places in your piping system.

more in "Chapter 2"
 
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Old 10-02-08, 06:07 PM
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Chapter 2

There is a device on your boiler that will allow water to feed into the system when the pressure drops below 12-15 PSI.

When your pressure relief valve opened at 30 PSI, some water was discharged. This was SOME of the extra 4% volume from when the water got hot. When that water cooled again after the boiler shut off, there wasn't enough water in the system, and the feed valve let some back in. This cycle would repeat with every boiler cycle.

Fresh water has LOTS of air dissolved in it. When you heat fresh water, that air is driven out of the water. That air goes to the high spots in your piping system. Air in the pipes can cause problems with the water not circulating. It's very possible that you have a LOT of air trapped in your system.

You need to let that air out ...

more later, got some things to do ...
 
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Old 10-06-08, 06:29 AM
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How to release air from the heating system

HI NJ Trooper,
Understood ,please suggest me how to remove the air form the system ?
I would appreciate your advise.
regards
 
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Old 10-06-08, 04:16 PM
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Air from the system

Hi NJ Trooper,
There are two copper lines going out from the boiler for two floors .
Each Line has a stop valve with a drain port for water .

Can you please suggest how to flush out the air from the system?
I would appreciate your reply

Thanking you
rajan
 

Last edited by NJT; 10-06-08 at 06:23 PM.
  #12  
Old 10-06-08, 06:28 PM
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Hi Rajan,

Please tell us what kind of heat emitters that are installed in your home. Are they 'fin tube' baseboards ? or cast iron radiators ? or ?

If they are baseboards, look inside the cabinets, at the end of the tubing run, and see if there are small valves that operate with a coin, or a screwdriver, or a square 'clock key' . If you find them, they are for bleeding the air out of the system.

Open them first with the boiler not running and allow the trapped air to escape, then run the boiler and while the water is circulating, BEFORE it gets TOO HOT!, open them again and see if more air will exit.

I need to look at your pictures again ... there may be something you can do at the boiler also.
 
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Old 10-06-08, 06:43 PM
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I looked at your pictures again, and one thing that I did NOT see was a device called an 'air separator' or 'air scoop'. I also did not see a device called an 'automatic air vent' or 'float type vent'.

These devices are intended to collect air in the system and vent it out. If they are not there, it will always be a problem for you to keep the system free of air.

In picture #4, on the right side, there are two drain valves, and below that, two shutoff valves. If you can not find any air bleeders on your baseboards, you will have to use those to flush out the air. Don't do that yet though, look for the manual bleeders first, and report back what you find (or DON'T find) The problem is going to be that once we do that, the fresh water you add will release MORE air when it is heated, and with the absence of the 'air scoop' and 'air vent' noted above, that air will again be trapped in the heating loops.

Is the pressure still under control ?

Is the system heating the house properly ?

Do the pictures show ALL of the piping ? Is there anymore piping near the ceiling that may have an air vent device attached to it ? Look for small brass cans with a cap on top.
 
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Old 10-07-08, 06:02 AM
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Air Seperator

Dear NJ Trooper,

I have uploaded some new clear pictures of the Boiler ,Baseboard and copper pipe connections. I could not locate any device like Air scooper or seperator?

The end of the base boards are brazed to the copper piping lining .I suppose they are Fins kind ? I am not sure .
http://s374.photobucket.com/albums/oo182/rajan1011/
Please advice me the next course of action ?
and also recommend .how and where I can get the air scoop installed in the system.
I would appreciate your reply and thank you for all your help

regards

Rajan
 
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Old 10-08-08, 05:25 PM
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pictures

Hi NJ Trooper,
I hope the new snaps are clean and clear?
Please let me have your advice
regards
Rajan
 
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Old 10-08-08, 06:37 PM
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Hello Rajan, yes the new pictures are good enough to see that you do have 'fin tube baseboards' installed in your home.

Have you looked at all of them ? I hope that at least ONE of them has an air vent on it. I am not so sure though, because if you do not have an air scoop or an automatic air vent on the boiler itself, I doubt the installers would have put them on the baseboard either.

There is another way to flush the baseboards, but as I explained earlier, you will be adding a LOT of fresh water to the system, and once you do that, MORE air will come in with the fresh water.

In this picture please notice the 'lever' on the bottom of these controls. These levers will allow you to manually open these ZONE VALVES.



In this picture, there are four red handle valves and a brown bell shaped valve with a lever on top. The two red handles on the bottom are 'shutoff' valves, and on the top are drain valves. The lever on top of the brown valve is a 'fast fill' valve.



Turn off the boiler and let it cool below 100F.

Connect a garden hose to one of the drain valves and run it into the laundry tub in the basement.

Close BOTH of the red shut off valves.

Move the lever on the bottom of the zone valves to the MANUAL OPEN position.

Open the red drain valve with the hose on it.

Lift UP on the lever on top of the brown valve.

Let the water run through the system until there is no more air coming from the garden hose.

Put the lever on the brown valve down, and close the drain valve with the hose.

Move the hose to the other drain valve.

OPEN the drain valve.

Repeat the process of lifting the lever on the brown valve and allowing the water to run until there is no more air.

Put the lever on the brown valve down, close the drain valve and remove the hose.

OPEN both of the red shutoff valves.

Return the lever on both zone valves to the AUTOMATIC position.

You should now have removed most of the air from the system. Make sure that all the valves and levers are returned to their previous positions and turn the boiler back on.

However, since there is no device on your boiler that I can see (air scoop, or automatic air vent) you will ALWAYS have trouble with air in this heating system. The solution is to have an air scoop and automatic air vent installed by a plumber.
 
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Old 10-19-08, 06:10 AM
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Thanks!

NJ Trooper --

Your answers seem perfectly suited to my situation as well, but would like some advice.

My system has been heating properly in the basement and on the main level. However, I haven't had circulation on the top floor. A friend said that this sounds like air in the system (which is confirmed by some of your answers with Rajan). But, my 30 PSI relief valve has also developed a constant drip, no matter how much pressure is in the system. If I open the valve, water gushes and I can only limit the flow by pressing DOWN on the relief valve. I can here the flow stop when I press on it. Then I can hear a slight trickle when I let go. Does this need to be replaced before I drain the system, or in tandem?

I have checked for air release valves on the top floor, but haven't found any. Also, there doesn't seem to be any air scoop or separator.

Should I follow the same basic steps you laid out for Rajan?

Thanks in advance. I can post pictures if you like.

Claude
 
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Old 10-19-08, 07:25 AM
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Hi Claude, yes, let's start with pictures... you know how to do ?

If the boiler pressure gauge says like 12-15 with system cold, and the relief valve is weeping, and the valve is more than 5 years old, I would replace it. Before any 'how-to' though, I'd like to see the pics...

It does sound like air is preventing the circulation, when you say 'top floor' I'm assuming you mean 2nd floor ? and boiler is in the basement ?

What is the normal COLD pressure on the boiler, and how high does it go when it gets HOT ?
 
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Old 10-19-08, 11:18 AM
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Pics to follow...

NJ Trooper...

I will post pics sometime today, as soon as possible, because I would like to work on the system this evening and tomorrow morning -- a cold front is coming!

My home is a tri-level with a basement, so really has 4 levels but three zones.

Thank you and I look forward to discussing with you later today.

Claude
 
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Old 10-19-08, 07:52 PM
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Pics of system

Here is the link to pics of my boiler system. http://s450.photobucket.com/albums/qq228/claudesamm/

I am very much looking forward to your advice. Is it worth it for me to just call someone, or is this a reasonably straightforward process?

Thanks again,

Claude
 
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Old 10-19-08, 08:36 PM
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I truly feel sorry for anyone that has to work on that system. Whoever installed it in that corner should be shot. Same goes for whoever allowed that installation to pass inspection.
 
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Old 10-19-08, 09:07 PM
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Originally Posted by furd View Post
I truly feel sorry for anyone that has to work on that system. Whoever installed it in that corner should be shot. Same goes for whoever allowed that installation to pass inspection.
LOL...and thanks for your sympathies. However, it's got to be done. I'm pretty sure I've got a grip on it. Just want to double check before I start the process.
 
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Old 10-20-08, 08:14 PM
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NJ Trooper,
have you had a chance to review the pics?

thanks again,
Claude
 
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