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Old 10-24-2011, 02:54 PM   #46
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pressure relief valve is leaking on boiler


It can be bleed with or without the boiler running. I prefer to do it with the boiler not running, as air can be moving in the water fast enough that it does reach the rads while your bleeding them.

How high is the top of your highest rad from the boiler. You need enough pressure to each this height.

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Old 10-24-2011, 03:35 PM   #47
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pressure relief valve is leaking on boiler


I think its about 17 feet from the top of the boiler to the top of the radiator on the 2nd floor.
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Old 10-24-2011, 03:40 PM   #48
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pressure relief valve is leaking on boiler


Then 12 PSIG is plenty, as that will raise a column of water to a height of 27.6 foot.
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Old 10-24-2011, 03:43 PM   #49
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pressure relief valve is leaking on boiler


No vent cap on tank. But we did notice a screw above drain area. Can I open it to let air in?
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Old 10-24-2011, 03:45 PM   #50
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pressure relief valve is leaking on boiler


Don't know, as i don't know what screw you see.
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Old 10-24-2011, 04:07 PM   #51
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pressure relief valve is leaking on boiler


the expansion tank drain. Father has finger on it
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Old 10-24-2011, 04:09 PM   #52
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pressure relief valve is leaking on boiler


and there is a hex type screw on belly of tank. We think its there to completely drain tank.
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Old 10-24-2011, 05:47 PM   #53
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pressure relief valve is leaking on boiler


Quote:
Originally Posted by beenthere View Post


Number ONE reason those auto feeds your talking about are left open. Is that the installer isn't willing to take the time to bleed and purge the system like he is suppose to. A form of laziness.


The only time that i will close one if the system has glycol in it.

Other wise the prv stays open..

And no it is not laziness to keep it open..
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Old 10-24-2011, 06:00 PM   #54
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pressure relief valve is leaking on boiler


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and there is a hex type screw on belly of tank. We think its there to completely drain tank.
No, its just another tap for different types of set ups.

Use the union on the pipe going to it from the boiler.
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Old 10-24-2011, 06:04 PM   #55
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pressure relief valve is leaking on boiler


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The only time that i will close one if the system has glycol in it.

Other wise the prv stays open..

And no it is not laziness to keep it open..
If its ok to close it because the system has glycol in it, its ok to close it if its 100% water.

There is no good reason to leave it open. Other then a tech doesn't want to come back and add water and purge/bleed the system.

Fresh water is an enemy of boilers.
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Old 10-24-2011, 07:40 PM   #56
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pressure relief valve is leaking on boiler


not sure why keep shuting off expanison tank this is the part that keeps relief valve closed when heating water.....so install new relief the proper way drain expanison tank start to fill system and bleed rads....after all air is out of rads ..take pressure to about 12-14 lbs...and turn off inlet water to boiler this will isolate your feeder......boiler should work fine.....after a day open inlet valve again see if problem returns.....
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Old 10-24-2011, 08:29 PM   #57
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pressure relief valve is leaking on boiler


Expansion tank is only shut off to drain it.
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Old 10-24-2011, 10:37 PM   #58
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pressure relief valve is leaking on boiler


We did a few things to test system

1. checked aquastat relay: it was set to 220 so I lowered it to 180.
2. shut of water to boiler
3. checked PSI at 18
4. expansion tank open
5. put thermostat to 74

Boiler was on 90 minutes went to almost 30 PSI. Boiler shut off, house was very warm. Hasn't cycle back on yet. Checked it about 2 hours later, house still warm, PSI has dropped to 20 PSI and boiler hasn't turned back on.

So far, with the exception of the PSI running between 18 - 28, the boiler and radiators are acting okay.

So we are thinking about replacing water feed valve, if we do, do we have to drain the boiler and radiators?

the picture below shows the water feeder valve and the water shut off to boiler

what if it turns out the water feeder valve is okay, its the shut off valve from the city water that leaks?
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Old 10-25-2011, 04:19 AM   #59
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pressure relief valve is leaking on boiler


What your describing is an expansion tank that is almost full of water. You can change the PRV, but that won't correct the problem of the tank being to full.

Drain it fully.
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Old 10-25-2011, 07:30 PM   #60
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pressure relief valve is leaking on boiler


look to see if you can change out old expanison tank to precharged new style expanison problems gone......if old tank is going to stay in system they make a combo drain ...where it lets air in as it drains water out?????

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