High PSI After Bleeding Air From Gas Boiler

Reply

  #1  
Old 01-21-15, 05:20 AM
D
Member
Thread Starter
Join Date: Jan 2015
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
High PSI After Bleeding Air From Gas Boiler

Hello everyone! I recently bought a 2,500 sq ft ranch house that has a 30+ year old Utica gas boiler for my 3-zone hot water baseboard heat. A few weeks ago I heard what sounded like the ocean running though my bedroom basebaords. After doing some research on this forum I determined that the problem was most likely air in the system. This past weekend, I followed the instructions I read on here and bled the air from the zone that fed my bedroom. I THINK I did this correctly because the sound of the ocean running though my bedroom is gone and I don't hear any noise when the heat kicks on.

The problem is that before I bled the air from the system I noitced that the psi on the boiler was at 10-12psi when hot and running. However, after bleeding the air, the psi is now about 20 when hot. It has stayed at 20 for the past few days until this morning when I noticed it at 25psi. I became concerned that it was going to keep rising and trip the pressure relief valve, so I shut the boiler off this morning. I'm waiting until the boiler cools down to see what the "cold" temp/pressure drops to.

I admit that before reading this forum over the past 2 weeks I knew nothing about boilers and how they operate (and even now I'm not entirely sure how my setup works...i.e. i'm not sure how I can shut off/isolate one zone from the others, because I dont have any "yellow" handle shut off valves near the spiget valves where i bled the air from??).

I've attached some pictures of my setup and would appreciate any help i could get from the experts on this forum. Thanks!

delo2310's Library | Photobucket
 
Sponsored Links
  #2  
Old 01-21-15, 07:24 AM
D
Member
Join Date: Jan 2015
Location: USA
Posts: 95
Received 0 Votes on 0 Posts
Check your expansion tank, there's a sticky instruction at the top of this forum. It could be that once you got the air out, there's no place for the water to expand.
 
  #3  
Old 01-21-15, 07:36 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Yes, agreed...

It's also possible that after operating the fill valve that some 'crud' from the water line has gotten into the valve and it is now slowly leaking through.

This is the problem with plumbing... you touch one thing and you end up having to touch all the things!
 
  #4  
Old 01-21-15, 07:55 AM
D
Member
Thread Starter
Join Date: Jan 2015
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Thanks for the quick reply guys! I am at work right now but when I get home tonight I will test out the expansion tank using the instructions at the top of this forum.

DogTo - Can you further explain what you mean when you say that once "I got the air out there is no place for the water to expand"? Is it possible that I took the air out of the expansion tank as well as the pipes leading to my master bedroom? That was one of the issues I was having when I tried to bleed the air out of the zone going to my bedroom. I couldn't figure out how to isolate just that one zone before opening up the spigot valve to bleed the air from that zone?

Many of the pictures i've seen on here of other people's systems all seem to have a yellow handle on each zone near the spigot releif valve that they can open or close before they bleed the air. I dont have any yellow handles near my spigot relief valves? So I wasn't sure if I was bleeding the air from just that one zone or from other places as well? It seems to have worked (since i dont hear the ocean in my bedroom anymore) however, I might have screwed something else up in the process...lol
 
  #5  
Old 01-21-15, 11:31 AM
D
Member
Join Date: Jan 2015
Location: USA
Posts: 95
Received 0 Votes on 0 Posts
The expansion tank is in the system to give the water someplace to expand, part of that expansion tank should have air in it. If it doesn't the water is trying to expand against all the metal or what ever your system is made of and if it's metal, it's like when you freeze water in a closed pipe (water expands both with heat and cold), it has to go somewhere, in your heating system it's the safety valve if the expansion tank isn't working right or the pressure goes up when the water temp goes up. If your expansion tank isn't working right, use minimum pressure in your system until you get it fixed. Yes, sometimes those pressure regulators from the supply crap out, mine quit after about a year, so I just turn off the supply and keep an eye on the boiler pressure.

Maybe NJ can address the yellow handle, I'm not real experienced on all the systems. When I put mine in I put drains and valves on each end of each zone so I could work on each one independently, some guys don't do that and when you want to work on the system it gets hard or you have to drain the whole thing, plus it makes bleeding hard. But if your expansion tank, air scoop and auto vent is working right it should bleed itself. You may need a new auto vent too they seem to get full of calcium depending on your water, I change mine once in a while they're only about $10.
 
  #6  
Old 01-21-15, 12:18 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Maybe NJ can address the yellow handle
Some installers will rely on the zone valve to act as the 'stop' valve below the drain... looks like that's what they did on your system.
 
  #7  
Old 01-22-15, 04:25 AM
D
Member
Thread Starter
Join Date: Jan 2015
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Guys - I went home last night and took your advice to check out the expansion tank. I followed the instructions on the sticky posted in the forum, but I couldn't get the pressure on my boiler to drop all the way down to zero like the instructions said. I drained about 5-6 gallons out of the boiler from the three different zone valves and the main drain valve. This dropped the pressure on the boiler from approx. 25-27psi to about 8psi. After draining the 5-6 gallons the water slowed to a trickle, and I got scared i was going to completely drain the boiler (since the instructions on the sticky said DO NOT DRAIN THE ENTIRE BOILER!). How do you drain the system and drop the pressure to zero without completely draining the boiler? How do I know how much water is in the whole system?

After i got the pressure down to 8psi I checked the expansion tank and there was ZERO pressure in the tank. The bladder wasnt leaking at all, so i just recharged the tank to 12psi. After opening up the main water valve and the air vent on the tank I fired the boiler back up. I turned the heat on for 2 of the 3 zones and watched the pressure stay between 24-27psi last night and again this morning. I checked the pressure in the expansion tank this morning at it was charged to about 15psi (the boiler was on and running when i checked it). Also, the auto vent on top of the expansion tank seemed to be working because I heard it kicking off air every few minutes.

I'm assuming that since I didnt get the boiler pressure down to zero before I charged the expansion tank, this is the reason my pressure is still running pretty high. Any suggestions on how to get it to zero without draining the boiler? Or do you think it is OK to run the boiler at this pressure? Will it gradually build up over time and trigger the pressure release valve?

Thanks again for all of your help! I'm learning more and more every day!
 
  #8  
Old 01-22-15, 06:03 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Delo, everything you are saying is indicating to me that your boiler pressure gauge is a lying POS.

Please read this:

http://www.doityourself.com/forum/bo...ure-gauge.html
 
  #9  
Old 01-22-15, 06:57 AM
D
Member
Thread Starter
Join Date: Jan 2015
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
NJ - That thought did cross my mind last night but I didnt have the materials to build my own gauge to check the pressure. I will follow the instructions on how to verify the boiler pressure and let you know what i find.

a few dumb questions though....is the pressure relief valve tied to the pressure gauge on the boiler? Or does it have its own internal pressure mechanism that will trigger the release valve when it indicates it reaches 30psi as opposed to when the gauge on the boiler "says" it reached 30psi....which might or might not be the case if the gauge is faulty.

Also, do I need to drain the boiler again (like i did before I re-pressurized the expansion tank) to test what the real pressure of the boiler is? Or do I only need to drain one zone and then test the pressure from that open releief valve? Not sure i fully understand after reading the sticky on how to verify the boiler gauge.

Thanks!
 
  #10  
Old 01-22-15, 07:22 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
is the pressure relief valve tied to the pressure gauge on the boiler? Or does it have its own internal pressure mechanism that will trigger the release valve when it indicates it reaches 30psi as opposed to when the gauge on the boiler "says" it reached 30psi
Pressure relief is 'stand alone'. It doesn't care what the gauge says. If it thinks the pressure is 30, it opens.

Also, do I need to drain the boiler again (like i did before I re-pressurized the expansion tank) to test what the real pressure of the boiler is?
No, when you put that gadget together and screw it onto a spigot, and open the spigot, the gauge will read whatever pressure is in the system at that time.

The only thing that will change from one spigot to another would be if one were significantly higher or lower ALTITUDE wise. In a closed system pressure will change with the ALTITUDE that you are measuring at. It would change by 0.432 PSI per foot of altitude change.

So, if one spigot is ten feet higher than another, you would read 10 X 0.432 = 4.32 PSI LESS on the higher altitude gauge.

For most purposes the measuring points will be within a foot or two of each other in altitude, and the pressure difference can be disregarded... not enough to make a difference.
 
  #11  
Old 01-22-15, 08:15 AM
D
Member
Thread Starter
Join Date: Jan 2015
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
NJ - Thanks for the clarification! The spigots for my 3 zones are all right next to each other so I will just check one for the correct pressure.

Is it safe to assume that the "actual" pressure will be approximately 8psi different than what the boiler is reading? I'm basing this assumption on the fact that when I tried to drain the boiler down to zero, I still had 8psi remaining on the gauge.
 
  #12  
Old 01-22-15, 08:52 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Is it safe to assume that the "actual" pressure will be approximately 8psi different than what the boiler is reading? I'm basing this assumption on the fact that when I tried to drain the boiler down to zero, I still had 8psi remaining on the gauge.
Not safe to assume that the 8 PSI difference will be 'linear' across the range.

In most cases, as the pressure increases, so does the error.

You may be 8 PSI off at actual ZERO, but could be 15 PSI off at 20 PSI...

OR not... different failure modes, different problems.

But yours sounds as if the difference increases as the pressure does.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: