Pressure Relief Valve leaking

yekasi

hello.

I have a weil mclain CG Boiler (CG-5-SPDN Model) and my pressure relife valve is leaking water. It first started with a few drips about 3 weeks ago, and eventually right now it has become a slow stream of dripping. For time being, i used some PEX piping to route into a pump to avoid the floor getting wet. The water that it leaks out is hot.

I have a fairly complex system, i feel… i bought the house like this, and it has 4 zones like below,

• 1st floor
• 2nd floor
• Sunroom (Radiant heat)
• To the water heater

I feel like the person who put this together didnt group them and i have pipes going all over the place. Fortunately, each zone has its own release bip and water valve.

There is 1 expansion tank for the boiler itself, and there is another expansion tank for the water heater. However, the expanion tank to the boiler itself is upside down, not sure if this is a problem. The boiler gauge itself has a 30 psi.

I am posting the pictures of my setup. I suspect it may be be a bad expansion tank , and also sediment on the pressure relief valve. I have already bought the replacement of the pressure relief valve , but the space is so tight , i may end up calling a professional to help me with it. However, i want to do some basic troubleshooting, so if i do call a professional, i know what i am dealing with.

• Can you let me know how i should troubleshoot this? The pressure relief valve is the one towards the back, with a WHITE PEX pipe (I installed it for time being just to route water away)

• Can you tell me how to troubleshoot the expansion tank?

• Can you tell me what is the best way to drain (i think its also called bleed) the system to replace the expansion tank and also the pressure relief valve? (If needed)

• How old is my boiler and how old is my expansion tank? They look fairly new.

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Jamie Hall

Goody. There's a valve between the expansion tank and the rest of the system! To check the expansion tank, which may be at least part of your problems, the procedure — since you have that valve — is pretty simple.

In principle anyway.

Close that valve.

Now with the aid of at least two very strong gymnastic helpers, unscrew the tank from the valvve. Warning: if that thing has failed it is going to be full of water and thus very heavy. VERU heavy. It may easily weigh as much as 300 pounds. If you can contrive a way to support it as you unscrew it, you will be much happier…such as a good sling from the overhead which won't slip off. You may be able to drain any water in it — or at least some of the water in it — before you try to lower it. That will help.

Now drain it completely. Easiest way to ensure that it is drained is to have it with the water connection down and apply air pressure to the Schrader valve at the top. At this point you can also add air — again with that Schrader valve — to two or three pounds less than your cold system pressure. Check that it holds air.

If it does, you're good to go. If it doesn't, hoist it back up again and screw it back onto the valve and open the valve and you're done.

EdTheHeaterMan

There is an easier way to check that tank.

1. Using a tire pressure gauge check the air pressure on the tank. The test port is on the top of that tank the way it is installed.
2. If you get any water to squirt out of the air side of the tank, STOP!  You need to replace the tank.  If you do not get water on the air side of the tank then go to step 3
3. Turn off the boiler and allow it to cool off (may take a few hours)
4. Reduce the boiler pressure to about 5 PSI by draining water from the boiler at one of the purge valves.
5. Close the valve between the tank and the system
6. Check the air pressure on the expansion tank using a tire gauge that will measure about 12 PSI accurately. If the tank is below 12 PSI then you need to add air.
7. Use a bicycle pump or compressed air to fill the tank with air.  Be careful if you are using a compressor that has more that 50 PSI pressure.  You only want about 12 PSI so you will need to add short bursts and measure until you get to 12 PSI.  
8. If you go over 12 PSI, then you will need to let some air out of the tank just like letting air out of a tire.
9. Once you have 12 PSI back in the tank you can then put your boiler pressure back up to 12 PSI.  then open the valve between the boiler and the tank and you should be good to go.

EBEBRATT-Ed

I would also replace that bad looking air vent on the boiler while you are shut down. System pressure should be 12-15 when cold. The pressure may rise to 20-23ish when the boiler is hot. If it goes close to 30 you would need a larger expansion tank. Make up water regulator should be set to 12-15 psi also.

Relief valve opens at 30ish pounds.

tcassano87

I dont think anyone’s mentioned this yet but your indirect tank could have crack in the coil causing this pressure increase inside the boiler. If you gauge is reading 30psi then the relief valve is doing its job. Turn the feed and return valve off to the InDirect, release some pressure on the boiler and see if the problem continues. If it doesn’t your tank is compromised

Usually it’s one of 4 things…the relief valve, the expansion tank, the boiler feed OR worst case scenario the In Direct is cracked

Grallert

If that extrol is There's no way I'd attempt to remove it with out draining it. It'll come down like a wrecking ball. Drill a hole in it and drain it.

yekasi

https://forum.heatinghelp.com/discussion/comment/1834574#Comment_1834574

the boiler gauge reads 30 psi.

yekasi

» I would also replace that bad looking air vent on the boiler while you are shut down

Can the air vent be switched with later on or it has to be drained/off while i replace the expansion tank?

i cannot really see what make/model it is already. What is the giudeline to pick a new air vent from supplyhouse?

Larry Weingarten

Hi, There is mineral buildup on the vent, evidence of water running down the sides of the vent, and a rusty pipe underneath. All of these point to a failed vent.

Yours, Larry

yekasi

https://forum.heatinghelp.com/discussion/comment/1834784#Comment_1834784

i am trying to buy a new airvent from supply house but i am not sure which one it is. I have cleaned it a bit and took some pictures, can you let me know which model/make is it ?

i thikn it is this one:

https://www.supplyhouse.com/Taco-400-4-1-8-Hy-Vent

hot_rod

that looks like an 1/8” vent. Here is a good option.

If you wanted to change the fitting below, this 1/2” model has a safety cap that would protect against leaking if the needle valve inside fails or gets scale under it.

IMG_0960.jpeg

IMG_0961.jpeg

EdTheHeaterMan

In that location the air vent is a 1/8" HyVent. and can be replaced with any of the generic air vents. Taco, Maid-o-mist, Caleffi 502610A. and Honeywell Braukman even has them. It is a pretty standard Supply House part that is often replaced on a regular basis. I would replace at the same time as the tank service because both require draining off the pressure. Maybe not the entire system, but you need to have no pressure on the boiler when you swap them out. I have done both those jobs "On The Fly" (expansion tank, relief valve, air vent and other items) by just getting the boiler pressure to zero and having the replacement part ready with pipe dope and a quick hand. Minimum water loss.

As far as your expansion tank is concerned, there is a valve to isolate the boiler from the tank so that makes it easier. But you should make sure the tank is empty before you attempt to remove it.