Pressure Relief Valve leaking

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Takkie

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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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Fitter30

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One of two problems either the boiler system is overfilled or the expansion tank has failed. Ex tank opposite piping end of piping is a plastic cap that unscrews with a schrader valve to measure air pressure. Tools needed tire gauge 0-50 lb and a tire pump or air compressor. Right of boiler black pipe with blue handle valve look left yellow handle valve turn handle cw to off. Need to turn either turn the gas valve on boiler to pilot or if there is a switch turn that off hopefully the pumps will stay on. Boiler water needs to be 100° or cooler. Depress schrader valve with screw driver water sprays out tanks bad and needs to be replace. With pumps off water temp down pressure in boiler 10 lbs for one story 12 lbs for two story. Air pressure in ex tank to match boiler water pressure. Turn everything back on. Only see one air vent on boiler looks like it could be clogged with minerals. Don't see a air scoop or micro bubbler for air. Minneral deposits on pump flanges.
 
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Takkie

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One of two problems either the boiler system is overfilled or the expansion tank has failed. Ex tank opposite piping end of piping is a plastic cap that unscrews with a schrader valve to measure air pressure. Tools needed tire gauge 0-50 lb and a tire pump or air compressor. Right of boiler black pipe with blue handle valve look left yellow handle valve turn handle cw to off. Need to turn either turn the gas valve on boiler to pilot or if there is a switch turn that off hopefully the pumps will stay on. Boiler water needs to be 100° or cooler. Depress schrader valve with screw driver water sprays out tanks bad and needs to be replace. With pumps off water temp down pressure in boiler 10 lbs for one story 12 lbs for two story. Air pressure in ex tank to match boiler water pressure. Turn everything back on. Only see one air vent on boiler looks like it could be clogged with minerals. Don't see a air scoop or micro bubbler for air. Minneral deposits on pump flanges.

i think the expansion tank has failed. I knocked on it and i dont sense hollow in the lower (or upper since its upside down) part of the bladder area. It sounded like solid inside. I compared it with the expansion tank sound above the water heater, so i was able to determine the differences or sounds.

there is a boiler on / off switch, and i can turn that one OFF, and by turning that OFF, the pilot light wil stay on.

with the tank going bad, is there even any reason to check on the pressure of the existing bank?

If i just shut off all the valves going in/out of all the zones, and then just drain the boiler , would that be enough for me to just twist off the expansion tank for replacement? I am worry the water inside tank is so HOT that will burn me when i twist it off.
 

John Gayewski

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You don't have to drain anything. Shut the valve that is right at the expansion tank and unscrew it.
 

John Gayewski

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This is actually one of the many reasons not to mount an expansion tank upside down. Yes it will make a mess, but that's better than draining the system for a minor thing. You could be chasing air out of your system for a long time after draining it like your talking about.

I would rather clean up a small mess than be fiddling with my system for a long time. Some systems can take all day to fill and bleed properly.

You could take this time to move the expansion tank also. Just run a pipe to a convenient place and put the tank there. It's where the tank ties into the system that matters, not where the tank actually sits. Then you could mount it properly and it'll be easier next time.
 

Takkie

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This is actually one of the many reasons not to mount an expansion tank upside down. Yes it will make a mess, but that's better than draining the system for a minor thing. You could be chasing air out of your system for a long time after draining it like your talking about.

I would rather clean up a small mess than be fiddling with my system for a long time. Some systems can take all day to fill and bleed properly.

You could take this time to move the expansion tank also. Just run a pipe to a convenient place and put the tank there. It's where the tank ties into the system that matters, not where the tank actually sits. Then you could mount it properly and it'll be easier next time.
if i really shut the valve off right at the expansion tank and unscrew it... i can installed some metal wire to hang on to the wood beam above for the weight concern. but i dont know how to get the pressure out without draining... how can i achieve that?
 

Reach4

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but i dont know how to get the pressure out without draining... how can i achieve that?
I expect if you push the pin on the Schrader valve, that will let the pressure out.
 

Reach4

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I don't know if the weight is a concern.

I have not worked with a thermal expansion tank. I imagine weight could be a concern.
 

John Gayewski

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Put a towel on the floor and hang a bucket below you. If you unscrew it it will start dripping. Let it do that into a bucket for as long as you want. When it gets lighter, lift it off.

The whole thing won't try to dump it'll glug since there's no where for air to come in.
 
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