Over pressurized boiler system.
#1
11-12-18, 12:12 PM
Over pressurized boiler system.
I have been trying to figure this problem out probably for longer than i should.
I forget the name of my hot water / oil fired burner system. But the system seems to really like to build up pressure to about 30 psi, course it cant go above that because i have a working pressure relief valve.
I have replaced the expansion tank, pressure relief valve and the pressure reduction / auto fill valve. I have also been trying to purge air out of the system. There are 3 zones and 1 circulator in my setup.
I just cant think what else might be causing this except maybe there is air in the system causing these headaches?
I should also mention, the system when warm is only at about 12 psi. After running is when it really builds up pressure.
I forget the name of my hot water / oil fired burner system. But the system seems to really like to build up pressure to about 30 psi, course it cant go above that because i have a working pressure relief valve.
I have replaced the expansion tank, pressure relief valve and the pressure reduction / auto fill valve. I have also been trying to purge air out of the system. There are 3 zones and 1 circulator in my setup.
I just cant think what else might be causing this except maybe there is air in the system causing these headaches?
I should also mention, the system when warm is only at about 12 psi. After running is when it really builds up pressure.
#2
11-12-18, 12:41 PM
Group Moderator
Welcome to the forums.
Have you confirmed what the air charge is in the new tank ?
There is a sticky at the top of the boiler forum that explains it.
Have you confirmed what the air charge is in the new tank ?
There is a sticky at the top of the boiler forum that explains it.
#3
11-12-18, 12:47 PM
T,
Is there a tankless coil in your boiler for domestic hot water or do you have a separate hot water tank.
If your boiler does not run does the pressure remain stable @ 12PSI and only rises when heated to operating temp.
Is this an ongoing problem or something new.
With the limited info given it does sound like an expansion problem, so a few more questions.
What do you have for radiation. Cast Iron Rads or aluminum fin baseboard.
What size expansion tank did you put in and what was the pressure in the tank. If you have any CI rads or CI baseboard a #60 is the smallest tank that should be installed.
If you had air in the system you would hear water rushing and possibly not heat properly because air hampers water circulation in the system.
Pics would be very helpful if possible.
Hope this helps a little.
Is there a tankless coil in your boiler for domestic hot water or do you have a separate hot water tank.
If your boiler does not run does the pressure remain stable @ 12PSI and only rises when heated to operating temp.
Is this an ongoing problem or something new.
With the limited info given it does sound like an expansion problem, so a few more questions.
What do you have for radiation. Cast Iron Rads or aluminum fin baseboard.
What size expansion tank did you put in and what was the pressure in the tank. If you have any CI rads or CI baseboard a #60 is the smallest tank that should be installed.
If you had air in the system you would hear water rushing and possibly not heat properly because air hampers water circulation in the system.
Pics would be very helpful if possible.
Hope this helps a little.
#4
11-12-18, 01:24 PM
Originally Posted by spott
T,
Is there a tankless coil in your boiler for domestic hot water or do you have a separate hot water tank.
If your boiler does not run does the pressure remain stable @ 12PSI and only rises when heated to operating temp.
Is this an ongoing problem or something new.
With the limited info given it does sound like an expansion problem, so a few more questions.
What do you have for radiation. Cast Iron Rads or aluminum fin baseboard.
What size expansion tank did you put in and what was the pressure in the tank. If you have any CI rads or CI baseboard a #60 is the smallest tank that should be installed.
If you had air in the system you would hear water rushing and possibly not heat properly because air hampers water circulation in the system.
Pics would be very helpful if possible.
Hope this helps a little.
Is there a tankless coil in your boiler for domestic hot water or do you have a separate hot water tank.
If your boiler does not run does the pressure remain stable @ 12PSI and only rises when heated to operating temp.
Is this an ongoing problem or something new.
With the limited info given it does sound like an expansion problem, so a few more questions.
What do you have for radiation. Cast Iron Rads or aluminum fin baseboard.
What size expansion tank did you put in and what was the pressure in the tank. If you have any CI rads or CI baseboard a #60 is the smallest tank that should be installed.
If you had air in the system you would hear water rushing and possibly not heat properly because air hampers water circulation in the system.
Pics would be very helpful if possible.
Hope this helps a little.
I think its about a 5 gallon tank for expansion, its been about a year since i replaced it but i replaced it with same size as what was installed at the time. Tank came pre-charged at 12 and its still at that.
The boiler is about 10 years old, the issue started about a year ago.
There is a tankless coil for hot water.
Yes it will remain at roughly 12 psi for as long as its not heating up. Once it runs and gets hot it starts building pressure.
I did just observe operation and it seems the temp guage and the controls disagree greatly on how hot the water is. It was set for 180 as hi set point, the burner did not however shut off until it was over 210 ( hard to get exact with these gauges ).
What is a #60 tank?
#5
11-12-18, 01:47 PM
A #60 extrol tank is just the next size up from what you most likely installed and has more capacity for expansion.
Your expansion or extrol tank is sized by the size of your system. What size (BTU) is your boiler. Even though you have conventional baseboard you still may need a larger tank.
I asked about the tankless because you could possibly have had a pin hole leak in the coil which would continuously feed fresh water into the boiler but if that were the case your pressure would be continuously high and not just when running.
https://www.supplyhouse.com/sh/contr...0extrol%20tank
This may give you more info and options.
Your expansion or extrol tank is sized by the size of your system. What size (BTU) is your boiler. Even though you have conventional baseboard you still may need a larger tank.
I asked about the tankless because you could possibly have had a pin hole leak in the coil which would continuously feed fresh water into the boiler but if that were the case your pressure would be continuously high and not just when running.
https://www.supplyhouse.com/sh/contr...0extrol%20tank
This may give you more info and options.
#6
11-12-18, 01:54 PM
I made a couple of adjustments to the temp settings, i did not like how hot it was getting before turning off, which i think also explains why my hot water has been so extremely hot lately.
I will see how this goes for tonight, i am a bit tired took me much of this morning to replace a broken gauge on the boiler. Plumber that installed it either was significantly stronger than me or this thing was seized up really good. Had to bust out my 2ft breaker bar, which looked hilarious on my 15mm wrench.
I will get back to you tomorrow with more information.
Also, how odd, i have gotten used to HD near me that normally lists them by gallon capacity. Looking at this mine looks more like the #60 because its longer than its round but doesnt have a cradle to sit on the floor.
I will see how this goes for tonight, i am a bit tired took me much of this morning to replace a broken gauge on the boiler. Plumber that installed it either was significantly stronger than me or this thing was seized up really good. Had to bust out my 2ft breaker bar, which looked hilarious on my 15mm wrench.
I will get back to you tomorrow with more information.
Also, how odd, i have gotten used to HD near me that normally lists them by gallon capacity. Looking at this mine looks more like the #60 because its longer than its round but doesnt have a cradle to sit on the floor.
#7
11-12-18, 02:32 PM
T,
As you will notice the #30 is a 4.4 gal cap. & the #60 is 7.6 cap. These figures are how much heated expanded water the tank will hold.
The #60 just hangs from the pipe the same way the #30 does, just a larger tank. They also have floor models of different sizes for different applications.
Some guys think it's a strong man contest when installing things when it's not necessary. When I started out I used to do the same thing worrying about leaks then I started looking at other people in the trade that had half my strength and realized you don't have to be a body builder to install pipe and fittings. Thank God for extension bars though when needed.
As you will notice the #30 is a 4.4 gal cap. & the #60 is 7.6 cap. These figures are how much heated expanded water the tank will hold.
The #60 just hangs from the pipe the same way the #30 does, just a larger tank. They also have floor models of different sizes for different applications.
Some guys think it's a strong man contest when installing things when it's not necessary. When I started out I used to do the same thing worrying about leaks then I started looking at other people in the trade that had half my strength and realized you don't have to be a body builder to install pipe and fittings. Thank God for extension bars though when needed.
#8
11-12-18, 03:10 PM
How to preset the expansion tank pressure:
1. Depressurize the system by letting out water until the gauge drops to about 5 PSI*. (To minimize the amount of bleeding you will need to do later, shut off the drain valve promptly when the pressure gets to 5.)
2. Using a tire pump or bike pump set the expansion tank to have the cold boiler pressure for example 12 PSI. For this measurement use a tire gauge on the tank valve and ignore the system gauge.
3. Add water to the system to get the system back to the 12 PSI or so.
As the system is bled and more make up water added to get back to the desired cold pressure,, the spread between cold pressure and hot pressure will become greater. The expansion tank is used to keep the hot pressure from getting too large.
* Five PSI is suggested as the fully depressurized level for a basement boiler in a 2 story house. Perhaps 8 PSI for a 3 story house, or 3 PSI for a single story house.
1. Depressurize the system by letting out water until the gauge drops to about 5 PSI*. (To minimize the amount of bleeding you will need to do later, shut off the drain valve promptly when the pressure gets to 5.)
2. Using a tire pump or bike pump set the expansion tank to have the cold boiler pressure for example 12 PSI. For this measurement use a tire gauge on the tank valve and ignore the system gauge.
3. Add water to the system to get the system back to the 12 PSI or so.
As the system is bled and more make up water added to get back to the desired cold pressure,, the spread between cold pressure and hot pressure will become greater. The expansion tank is used to keep the hot pressure from getting too large.
* Five PSI is suggested as the fully depressurized level for a basement boiler in a 2 story house. Perhaps 8 PSI for a 3 story house, or 3 PSI for a single story house.
#9
11-12-18, 03:28 PM
Originally Posted by AllanJ
How to preset the expansion tank pressure:
1. Depressurize the system by letting out water until the gauge drops to about 5 PSI*. (To minimize the amount of bleeding you will need to do, shut off the drain valve promptly when the pressure gets to 5.)
2. Using a tire pump or bike pump set the expansion tank to have the cold boiler pressure for example 12 PSI. For this measurement use a tire gauge on the tank valve and ignore the system gauge.
3. Add water to the system to get the system back to the 12 PSI or so.
As the system is bled and more make up water added to get back to the desired cold pressure,, the spread between cold pressure and hot pressure will become greater. The expansion tank is used to keep the hot pressure from getting too large.
* Five PSI is suggested as the fully depressurized level for a basement boiler in a 2 story house. Perhaps 8 PSI for a 3 story house, or 3 PSI for a single story house.
1. Depressurize the system by letting out water until the gauge drops to about 5 PSI*. (To minimize the amount of bleeding you will need to do, shut off the drain valve promptly when the pressure gets to 5.)
2. Using a tire pump or bike pump set the expansion tank to have the cold boiler pressure for example 12 PSI. For this measurement use a tire gauge on the tank valve and ignore the system gauge.
3. Add water to the system to get the system back to the 12 PSI or so.
As the system is bled and more make up water added to get back to the desired cold pressure,, the spread between cold pressure and hot pressure will become greater. The expansion tank is used to keep the hot pressure from getting too large.
* Five PSI is suggested as the fully depressurized level for a basement boiler in a 2 story house. Perhaps 8 PSI for a 3 story house, or 3 PSI for a single story house.
Also wouldnt the pressure in the tank and in the boiler be the same? Aside of course from potential inaccuracies of the gauges themselves. What i mean is if i set the cold temp to be 3 psi in the expansion tank wont the cold pressure in the boiler be 3 psi? Or is that the point, low pressure in the boiler until the refil is turned back on?
#10
11-12-18, 03:43 PM
Group Moderator
So for a basement boiler in a single story house the psi on the expansion tank should be more like 3?
#11
11-12-18, 03:53 PM
T,
On the surface I cannot even interpret what A is trying to say. You DO NOT want to run or lower your tank pressure to 3LBS or anything less than 12PSI. Your boiler feed valve and your extrol come preset at 12PSI for a reason.
At 3PSI you will not even reach the first floor. The easy math is for every LB of pressure you get 2FT of lift. There is an exact number but this is the easy to remember way and will more than cover you.
In a perfect world you want the tank pressure to match the cold boiler pressure but that is often not the case and really doesn't make that much difference in a residential system.
To properly check your tank pressure it must be done at 0 pressure on the tank, not 5 or 3 or anything. 0 is the magic number, You must either be able to completely isolate the tank or remove it from the system.
On the surface I cannot even interpret what A is trying to say. You DO NOT want to run or lower your tank pressure to 3LBS or anything less than 12PSI. Your boiler feed valve and your extrol come preset at 12PSI for a reason.
At 3PSI you will not even reach the first floor. The easy math is for every LB of pressure you get 2FT of lift. There is an exact number but this is the easy to remember way and will more than cover you.
In a perfect world you want the tank pressure to match the cold boiler pressure but that is often not the case and really doesn't make that much difference in a residential system.
To properly check your tank pressure it must be done at 0 pressure on the tank, not 5 or 3 or anything. 0 is the magic number, You must either be able to completely isolate the tank or remove it from the system.
#12
11-12-18, 05:24 PM
Well, this time i went down and took some pictures, so far it seems like i did not need to.
To check the pressure i know this is not the recommended way, but man my expansion tank is on there, must have seized up because i was the one that installed it with a pipe wrench and this time i actually have a wrench that fits. So i closed all the zones, closed the valve on the return, shut off the water refill and then drained the boiler, not completely but for a few seconds after the pressure read zero.
I also found a different pressure gauge just to be sure, and this one gave me a reading of 0 psi on the expansion tank. Just about wanted to pull my hair out. I know i had checked this before installing it but maybe something is screwy with my digital gauge lol there is a reason i used analog gauges when i worked in electronics, well that and the battery could be dead and still give me amps or volts readings.
Anyway i pressurized the tank to about 12 psi hard to tell with this gauge since its meant for car tires.
Turned everything back on and waited for it to heat up. Sure enough the boiler is reading 12psi after reaching temp. I think the temp adjustments helped also though since it was closing in on boiling hot.
I will check it again tomorrow but pretty sure its going to be ok considering how easy it was to replicate the problem. Thank you everyone.
To check the pressure i know this is not the recommended way, but man my expansion tank is on there, must have seized up because i was the one that installed it with a pipe wrench and this time i actually have a wrench that fits. So i closed all the zones, closed the valve on the return, shut off the water refill and then drained the boiler, not completely but for a few seconds after the pressure read zero.
I also found a different pressure gauge just to be sure, and this one gave me a reading of 0 psi on the expansion tank. Just about wanted to pull my hair out. I know i had checked this before installing it but maybe something is screwy with my digital gauge lol there is a reason i used analog gauges when i worked in electronics, well that and the battery could be dead and still give me amps or volts readings.
Anyway i pressurized the tank to about 12 psi hard to tell with this gauge since its meant for car tires.
Turned everything back on and waited for it to heat up. Sure enough the boiler is reading 12psi after reaching temp. I think the temp adjustments helped also though since it was closing in on boiling hot.
I will check it again tomorrow but pretty sure its going to be ok considering how easy it was to replicate the problem. Thank you everyone.
#14
11-13-18, 04:55 AM
Checked the system again this morning and it is still doing good pressure wise and no new water poured out from the relief valve.
