Boiler leaking from hy-vent with pressure drop

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Old 11-13-19, 08:54 PM
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Boiler leaking from hy-vent with pressure drop

Today was a warm day so I turned off our hot water boiler. About two hours later, I noticed a good amount of water had leaked. I assume it was from the hy-vent because it looked like it had dripped down the expansion tank, onto the boiler and down to the floor.

The vent wasn't wet at this point. Both the vent and the expansion tank were replaced about two years ago. The expansion tank still is cool on the bottom and sounds empty when tapped.

I have several questions:

1. Would there be a reason the vent would suddenly leak when the boiler was shutoff? I tried to replicate the issue but had no luck.
2. The vent valve should be a 1/4 turn open, correct?
3. I noticed that when the system is running, the pressure of the boiler gets to 30psi. I thought I had read that for my Peerless boiler, the pressure should be at 25. Would this cause an issue?

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Old 11-13-19, 10:38 PM
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There is a T&P valve on your boiler that opens at 30psi. That would mean your operating pressure is too high. Even 25 is a little high. Typically it would be closer to 20psi. The arrow points to the T&P valve line.

The vent valve should be open but with age they get corroded and leak. I've had to replace some almost every year depending on the mineral content in the water.
 
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Old 11-14-19, 07:34 PM
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This makes sense with where the water was leaking. I have replaced the Hi Vent and expansion tank. Is this valve something I can take care of myself since it looks like it just screws on? Also, with the pressure actually reaching 31psi this morning, what needs to be done to get the pressure into a correct range? Being handy, is this something I can handle or not? Thanks for the thoughts.
 
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Old 11-14-19, 10:04 PM
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Sorry PJ but you are WRONG! Boilers do NOT have T&P (temperature and pressure) relief valves, they have pressure only safety valves.

pisti, your problem is NOT the safety valve but IS most likely the expansion tank. It has "lost the air cushion" which means the diaphragm may be damaged which would necessitate replacing the tank. You may be lucky and only need to pump up the air cushion via the tire valve on the bottom of the tank. You can use a hand pump to add air through this tire valve up to a maximum of about 15 psi.

It is possible that you also have a leaking pressure reducing valve that is continually adding water.
 
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Old 11-16-19, 01:32 PM
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I just checked the expansion tank and the pressure is 9-10psi. No water is coming out of the Schrader valve on the tank either.

Do I need to remove the expansion tank in order to add pressure to it? Also, just so I am clear. The lower pressure in the tank means that the systems pressure would rise?
 
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Old 11-20-19, 08:31 AM
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Hi, I am checking back in to see if there is any guidance with my last question.

Do I need to remove the tank in order to pressurize?
Do I need to just isolate the tank, drain the water and then add pressure?
Or, can I just add pressure without doing any of the above?

Thank you!
 
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Old 11-20-19, 03:26 PM
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p,
To do anything with your extrol tank it must be isolated or removed and that includes taking pressure readings.

If you have an isolation valve between the tank and the boiler you can just close that valve and do what you have to do. If no valve is there you must remove the tank to check the pressure or recharge.

If removing it would be wise to install an isolation valve if possible.

Hope this helps a little.
 
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Old 11-20-19, 06:56 PM
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I isolated the expansion tank and add pressure back in to about 15psi. Once I opened the valves and turned 1 zone on, the pressure ended up rising to 40. It had been a steady 30 before I added pressure and my expansion tank was at about 10psi. What should my next steps be?
 
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Old 11-21-19, 07:36 AM
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I checked the boiler this morning and the pressure is around 38 now and the temp is over 200. The relief valve hasn't opened as far as I can tell. Could it be a possible bad gauge and how would I check this?
 
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Old 11-21-19, 02:09 PM
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See the "sticky" at the top of this forum: How to verify a boiler pressure gauge

But, you may have an unsafe condition. The maximum allowed working pressure of the boiler is 30 psi, and you may be exceeding that. 200 deg is too high. My advice is to shut down the boiler and call a professional whose referencesyou have checked.
 
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Old 11-23-19, 06:25 AM
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So they were ale to take. quick look at the boiler yesterday without doing any repairs left. The diagnosis was that there is a lot of air in the system and the auto fill probably has gone bad. They are coming back out today to bleed the system and then they are replacing the valve if need be. My questions is, they are charging about $1000 for the valve replacement, which seems extremely high. It seems like it is a $30-$40 part and simply screws on. Am I missing something here?
 
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Old 11-23-19, 02:30 PM
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p,
You are not missing a thing except probably the extra 800.00 you will be paying for the valve replacement.

Somewhere in your cold water supply going to the boiler you must have a shutoff before the valve and your pic shows one after the valve to completely isolate the feed valve for replacement and you are right, it does just basically screw on. I would shop around for a new company.
 
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