Boiler run at 25 psi all of the time, I thought it was suppose t

Joe.G

Hi, I have a old boiler (1947 York heat) My auto feed stops at 12 psi per the gauge on the back of the boiler, but as soon as it kicks on it goes up to about 25 psi and that is where it stays, the blow off valve never pops, is this to high of a pressure? I have a basement with one radiator, and 1st floor with 5 radiators and one baseboard and a 2nd floor with 2 radiators. I have a expansion tank model 30 extrol pre set from the factory at 12 psi. Is there anything I can do?

Unknown

The question is

whether the pressure is rising due to additional makeup water being introduced possibly due to pump/PRV orientation, is tank sized correctly for your system and is the tank charge actually 12 psi? The easiest way to seperate the first scenario from the last two is to introduce the 12 psi static fill and then shut off the cold water service valve to the PRV or feed valve. If the pressure no longer rises nor remains high after the boiler shuts down, you have found the problem. Hope this helps.

Glenn Stanton

Burnham Hydronics

Uni R

Ya know...

If your house is 50' high, 25psi is perfectly normal. First thing I'd do is bleed air from all of your rads.

techheat_2

Maybe

it's time for a new one, Its crazy to keep a 56 year old York running

Joe.G

I plan on replacing it next season, I just want to make sure it is running as good as it can run for the time being, I can not complain this boiler makes great hot water and heats the houes just fine.

So if I drain a little water out and let the auto fill stop on it's own at 12 psi shut the ball vavle so no water can get to the boiler, run the heat and then check the pressure and if it stays around 12 psi what would that mean problem wise? If it still goes up what does that mean?

all most postive that the air is out of the system, bleed the radtiators everyonce in a while and never get any air.

How can I tell how tall my house is I have a basment 1st floor and a 2ndfloor.

Earthfire

There's a lot of water

Volumne in that system.If that is a true cold fill at 12 psi. once the system heats up to 150 to 180 deg. that may be operating pressure with that size extrol. That old boiler alone probably holds as much water as a boiler and baseboard in a modern system

Dale

Rule of thumb

If you measure from the gauge on the boiler to the top of the rad on the 2 nd floor and divide by 2 that's close enough for pressure set on a cold fill. So, to the floor above the boiler say 6 feet and floor of 1st floor to floor of the second floor say 9 feet then say 3 feet to the rad top gives you 18 feet total divided by 2 or 9 PSI and then add 4 PSI to make sure you always have pressure on the top rad . You see why 12 usually works fine on most systems. You could do the .433 PSI per foot and add 4 psi but 12 PSI cold is fine for most houses up to 3 stories if the expansion tank is in the basement. I would follow the other posts advice and manually shut off the fill and see what happens, I think you need more air in your expansion tank given the jump to 25 PSI however the water fill is always worth a check.

Joe.G

I am going to check the air in my expansion tank, what should I set the pressure to? Should I check the air pressure first or should I set the boiler to 12 psi and shut teh water off to the boiler?

So if I drain a little water out and let the auto fill stop on it's own at 12 psi shut the ball vavle so no water can get to the boiler, run the heat and then check the pressure and if it stays around 12 psi what would that mean problem wise? If it still goes up what does that mean?

Rob T

Make sure that the

expansion tank has been shut off from the system and the water drained out to check the bladder pressure. It should read 12psi cold at that point. If it does then it sounds to me like the tank is ok. Depending on your boilers output and the total amount of water volume you have this tank may be on the small side.

If the system always returns to 12psi static once it cools down then it doesn't sound (to me)like a leaky fill valve as it should continue to creep up and show an increase even cold.

My system ('64 American Standard in a 2 story with approximately 180' of baseboard) starts at 12psi and tops at 20-22psi when it hits 190F. Where does your system high limit at? (Temp)



Rob

Bob_19

Is This

a gravity setup, or circulator pump setup?

1psi will lift water 2.31 ft, if your at 25psi generally your looking 58 ft/of head. This doesn't really take into account friction losses, so the true head could be less, or more

Joe.G

The pressure stays right around 25 to 26 psi all of the time hot cold it does not matter. I have a model 30 extrol tank on the system, when I re plumbed the house and took the tank off last year and checked the pressure it had about 6 psi in it, I refilled it to 14 psi, it probably had not been checked in 5 years. I plan on taking it off and checking it this weekend.

My system has a circulator on it. Thanks a lot and please keep the ideas comming.