Boiler Pressure too high?


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Old 11-27-07, 03:43 PM
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Boiler Pressure too high?

Hello
I recently purchased a 2 story house with a Utica hot water boiler. The boiler was off and drained when I took possession of the house and when I went to fill it I found the pressure regulator/fill valve was bad and was not flowing at all. The original was a 12 psi. The store I bought the replacement from only had a 15psi regulator and they said that it would be fine. Well after flushing and filling the zones im seeing about 18 psi on the gauge and 20 when the circulation pump is running and I havenít even lit the burner yet. Am I safe at 20? Should i expect an increase when the system is at operating temp? Thanks for any help

Chris
 
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Old 11-27-07, 03:58 PM
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Pressure

That cold pressure is a bit high especially if this is a 1 or 2 story house. Is the regulator adjustable?
 
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Old 11-28-07, 03:12 PM
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Originally Posted by Grady View Post
That cold pressure is a bit high especially if this is a 1 or 2 story house. Is the regulator adjustable?
Thanks Grady I checked It is adjustable. What is the proper way to set the pressure and what should it be at operating temp? Should i set it at 12psi cold with the circulation pump not running( it seems as though when the pump is running it increases pressure by 1-2psi) then light the burner? or is the idea to set your cold pressure such that when it is up to operating temp you are running at 12psi? Sorry First time with a boiler. Thanks again for your help

Chris
 
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Old 11-28-07, 04:49 PM
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Pressure

I would start at 10-12# cold & the circulator off. Once the system is hot, I would not be surprised to see 15-18#.
 
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Old 12-04-07, 12:21 PM
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I tried your last pressure recommendation and I have been tinkering with this for a couple of days now but I am unable to find a happy pressure for this boiler. Maybe im being too concerned but If I start with 12psi cold im seeing 25 psi before the burner turns off at approx 180-190 degrees. Seems a little to high. Running like this it is quiet and doesnít appear to be any air in the system Iím typically seeing a 10-12 psi swing in pressure through a burner cycle. So if I lower my initial cold pressure to around 10psi I see a max of around 22psi. A little better but it appears as though I have introduced a fair amount of air in the system as I can hear it in the pipes particularly when there is a call for heat after along shut down say over night and the system has had a chance to cool and the pressure bleeds off. Iím guessing with the cold pressure that low that that during the cool off and when the pressure subsides air is being pulled in through the auto ventors? If I rap on the expansion tank it is hollow about Ĺ - 2/3 ways up from the bottom and the top 1/3 or so is solid so im thinking it is ok? Does the pressure swing sound high for a 2 story house? This is an old house and each of the three radiators on the 2nd floor have to run from the basement to each room then down again instead of going upstairs and then going from room to room then down back to the boiler. Iím guessing this setup may require a little additional pressure to function properly. I was thinking of closing the auto ventors and bleeding the zones manually at the radiators with the current cold 10psi pressure and letting it go through a cycle. Thoughts? Thanks again for your help This site is a great service.
 
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Old 12-04-07, 01:00 PM
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If you bleed the rads on the top floor do you get water????? 18 psi should get you water at the 2 story.Do you get air or water out of the expansion tank schradervalve??
 
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Old 12-04-07, 01:16 PM
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Your expansion tank capacity is very marginal.

Is your expansion tank up between the joists? If so, it is nearly waterlogged and you'll need to drain it.

If you have the newer expansion tank that has the bicycle valve on it, you'll need to either remov or remove all of the pressure and then check with a tire gauge what the pressure is. If it is less than 15 psi, get a bicycle pump and set it right. If it's already at 15 psi, then you'll need either another one in addition or a bigger one.
 
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Old 12-05-07, 07:30 AM
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My expansion tank is located about a foot and a half above the boiler. As in my response to Ed there is air in it but I do not know the pressure. If I need to drain the system to test I will probably just replace it as looks at least a few years old.



Ed
If I bleed the rads on the second floor when the burner is at full temp and pressure is high 20-25 I get water with maybe a few very very very small burps of air. If I do this when the boiler temp is low and pressure is also low say 10psi I get nothing. I pressed the Schrader valve on the bottom of the expansion tank for a split second and I get air. Bottom half of the tank sounds hollow when I wrap on it with a screw driver.
 
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Old 12-05-07, 08:10 AM
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Tanks are cheap, but I'd still just reduce the pressure on the water to zero and then get that tank pumped up. If you've depressed that valve a few times then it totally explains what is happening. The only time the valve should be pressed is when it is isolated and you are touching it with either a gauge or a pump. Sorry if the post sounds parental in nature...
 
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Old 12-05-07, 08:28 AM
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Im with Who. Id check the expansion tank.
Out of the box here---- When the boiler is cold you have to put water in till you get water out of the top R/D or vent screw. The psi gauge can be off so what ever it takes to get water out of that top R.D is what you need. Then as the water heats up and expands the expansion tank has to take care of that.
lets just say thats kinda how it works
 
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Old 12-09-07, 02:34 PM
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Ok I let the system cool down then shut off the water supply before the regulator and opened the drain on the boiler as well as the valves I use for purging the system. I let the system drain for some time but I was never able to get the gauge to read less then 4-5 lbs and there was still a little water trickling out. Iím positive the shut off is working as I replaced it when I replaced the regulator. Is it possible the trickling water in the zones was enough to cause the 4-5 lb reading or is it more likely my gauge a little off? I tried to remove the expansion tank but the fitting is a little rusty and even with someone bracing the manifold im afraid that I will damage the pipes trying to remove it. So I took a pressure reading on the tank with a new gauge and it was 11psi I filled it to 12psi as that was what the tank said it was originally preset to. Let me know if I should still put 15 psi in the expansion tank per your previous recommendation. I refilled the system and set the regulator to 12 psi based on the gauge on the boiler and the system is still running at around 25 psi at full temp.
 
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Old 12-09-07, 03:28 PM
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Faulty Gauge

It would seem your gauge is off by about 5# but as a check, once the system is hot, check the pressure on the tank. It will be the same as the system pressure. Another way is to use a gauge which will screw onto one of the hose bibs. Some home centers carry them for use with sprinkler systems.
 
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Old 12-25-07, 05:41 PM
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All
Sorry for the delayed response. Just wanted to update you on my boiler issues. I checked the pressure on the expansion tank and with a gauge on one of the hose bibs and both are showing 15 psi when the boiler is at max temp so it would appear im of by 10 psi on the actual boiler gauge. When I get a chance im going to recheck the initial cold pressure with the gauge on the hose bib since I believe it is a little low as there is some persistent air in the upstairs zone that makes noise when the water temp is low. Otherwise the system is running good. Thank you for all the advice and have a great holiday.

Chris
 
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Old 12-25-07, 05:48 PM
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Thumbs up Running Well

Glad to hear the system is working well. Now you know the gauge is off by about 10#, you can get a new one & install it at your convenience.
It's our pleasure to help. All of us here wish you & yours a joyous holiday season as well.
 
 

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