Boiler pressure gauge

Reply

  #1  
Old 11-14-09, 06:26 AM
L
Member
Thread Starter
Join Date: Sep 2009
Location: NJ
Posts: 15
Received 0 Votes on 0 Posts
Boiler pressure gauge

Last night when my boiler was running the presure was over 30 psi which I am not sure if it is good cuz before when I bleed the 2nd floors radiators no water came out, just air, now water comes out when i bleed them my concern here is the presure to high? Last night water was driping while it run I check the presure this morning while COLD and it says 25 psi.
My question here is is the presure to hight and thats why it drips water??
 
Sponsored Links
  #2  
Old 11-14-09, 08:58 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, the pressure is too high...

You say it's dripping water, and that would be from the PRESSURE RELIEF VALVE, is that correct?

I'm posting the link to your photos...

Lizzy's Boiler

In an earlier thread (click here to view), you contemplated using your service plan to have someone look at your system. Did you do that? If so, what did they do?
 
  #3  
Old 11-14-09, 09:20 AM
L
Member
Thread Starter
Join Date: Sep 2009
Location: NJ
Posts: 15
Received 0 Votes on 0 Posts
I didnt have anyone coming I realized our warranty was up in october,

I believe thats is the relieve valve is the one on the last picture behind the furnace you can barely see it, if there is to much presure can you please explain to me how to reduce it by looking at the pics??? and when I do that does the boiler needs to be off?

Thanks in advance.
 
  #4  
Old 11-14-09, 09:43 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
If it's the one with the yellow tag on/near it, then yes, from what I can see it does appear to be your Relief valve.

I think the bigger question is why/how did the pressure increase in your system since that last thread! Then it was at 15 PSI, which should have been OK...

Let's look at this picture:



First, the water feed... the skinny pipe on the left side that comes down from the ceiling, first to a blue handle valve, then splits to a red bell shaped thing (that's your Pressure Reducing Valve), and another blue valve (don't touch this one, leave it tightly shut), then comes back together again, and down to another blue handle valve, then into the larger boiler piping.

If the red Pressure Reducing Valve is leaking, it will slowly cause the pressure to rise in the boiler. Same with the blue handle valve to the left of that. You won't actually SEE the water leaking, because it is leaking through the valve and into the boiler.

Where these pipes go into the boiler is a hose drain valve. Be advised that sometimes these valves don't close completely after being operated after a long time of being closed!

You can drain pressure off the boiler with that, or actually any other drain valve on the system. Hook up a hose, and slowly open the valve and watch the gauge. Drop the pressure to 15 PSI cold, and close the drain. If the drain valve does not stop dripping after you do this, you will need to go to the hardware store and pick up a brass cap to stop the dripping until the spring when you can change the valve.

After you close that drain, keep an eye on the pressure gauge for the next few days to see if the pressure starts to increase again. If it does, let us know and we'll tell you more.
 
  #5  
Old 11-14-09, 11:10 AM
L
Member
Thread Starter
Join Date: Sep 2009
Location: NJ
Posts: 15
Received 0 Votes on 0 Posts
when u say hook up a hose do u mean on that red valve all the way on the bottom? I apologize just want to make sure i do what u say, and the after i hook the hose ope the red and let water run until the presure is 15 psi?
 
  #6  
Old 11-14-09, 11:35 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
when u say hook up a hose do u mean on that red valve all the way on the bottom?
Yes, that one, or any other hose drain on the system will work to drop the pressure. Please remember that the valve may or may not completely close again if it hasn't been openend in a long time! If you have never had that one open, and there is another one that you have openend, and you KNOW closes without dripping it would be better to use one that you KNOW will close again...
 
  #7  
Old 11-14-09, 04:15 PM
L
Member
Thread Starter
Join Date: Sep 2009
Location: NJ
Posts: 15
Received 0 Votes on 0 Posts
Mr. Trooper you are awesome I got the presure to go down so now is 15psi, when cold, the valve luckily closed all the way. I apreciate all your help as always.
 
  #8  
Old 11-14-09, 04:21 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Great! Like I said, now keep your eye on the pressure and let us know if it starts to rise again... then we have to talk about why that might be...
 
  #9  
Old 11-15-09, 08:45 PM
D
Member
Join Date: Dec 2008
Location: Allegheny County, PA
Posts: 26
Received 0 Votes on 0 Posts
then splits to a red bell shaped thing (that's your Pressure Reducing Valve),
IS this installed correctly? All the PRV's I've seen say to mount horizontally (this one is vertical), with the adjusting screw facing up.
 
  #10  
Old 11-16-09, 07:59 AM
M
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by DA59a View Post
IS this installed correctly? All the PRV's I've seen say to mount horizontally (this one is vertical), with the adjusting screw facing up.
I looked at the B&G instruction manual for the pressure reducing valve. It does not explicitly specify the orientation of the PRV. But it does have a drawing of the "typical installation," which shows the valve with the adjusting screw pointing up.

The PRV's disc is held down on the seat with a spring. So, I "think" the orientation shouldn't matter.

I did learn something else from the instruction manual. B&G says that there must be a manual shutoff valve installed in the city water supply ahead of the PRV...and the shutoff valve must be kept closed except when filling the system. I had always thought that it was optional whether to run with the shutoff open or shut.
 
  #11  
Old 11-16-09, 11:34 AM
B
Member
Join Date: Sep 2009
Location: US
Posts: 25
Received 0 Votes on 0 Posts
I have a similar problem that's bugged me for quite a while. My boiler has always run at 20 psi. I seem to recall this being the case for as long as I've owned this boiler. I've replace pressure regulators twice to no avail. I can bleed it down to 5 psi and as soon as the boiler fires it will climb back to 20 psi as the temp rises. No air in the system. I suspected the tankless coil leaking, but pressure should continue to rise beyond 20 if that was the case since the cold water supply sits at 60+ psi.
 
  #12  
Old 11-16-09, 12:20 PM
M
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by boutym View Post
I have a similar problem that's bugged me for quite a while. My boiler has always run at 20 psi. I seem to recall this being the case for as long as I've owned this boiler. I've replace pressure regulators twice to no avail. I can bleed it down to 5 psi and as soon as the boiler fires it will climb back to 20 psi as the temp rises. No air in the system. I suspected the tankless coil leaking, but pressure should continue to rise beyond 20 if that was the case since the cold water supply sits at 60+ psi.
What is the pressure when the boiler is cold (room temp)?

20 psi may be OK when the boiler is hot. 5 psi is too low no matter what the temp is.

Have you verified that the expansion tank still has its air cushion?
 
  #13  
Old 11-16-09, 02:31 PM
B
Member
Join Date: Sep 2009
Location: US
Posts: 25
Received 0 Votes on 0 Posts
Originally Posted by Mike Speed 30 View Post
What is the pressure when the boiler is cold (room temp)?

20 psi may be OK when the boiler is hot. 5 psi is too low no matter what the temp is.

Have you verified that the expansion tank still has its air cushion?
Cold it will drop to about 15, 12-15 being the set on the regulator. Expansion tank is ok. Like I say it has always run at 20 psi when hot. It's not excessive by any means, but doesn't really need to be this high.
 
  #14  
Old 11-16-09, 03:48 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
manual shutoff valve installed in the city water supply ahead of the PRV...and the shutoff valve must be kept closed except when filling the system
I've wrestled with that myself... isn't there also a blurb in that I&O about having a proper LWCO installed?

My normal recommendation is that unless there is an LWCO, to leave the valve open...

Expansion tank is ok. Like I say it has always run at 20 psi when hot. It's not excessive by any means, but doesn't really need to be this high.
bouty, if the expansion tank is indeed OK, then it is what it is. The only way you would lower that HOT pressure is by fitting a larger expansion tank. The HOT pressure is a function of how much water is in the system (volume), the temp the water is heated to, and the acceptance volume of the expansion tank.
20 PSI is fine, stop losin' sleep!

But, how do you know it's "OK" ?
 
  #15  
Old 11-16-09, 04:11 PM
M
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by boutym View Post
Cold it will drop to about 15, 12-15 being the set on the regulator. Expansion tank is ok. Like I say it has always run at 20 psi when hot. It's not excessive by any means, but doesn't really need to be this high.
The pressure rise from cold to hot is determined by the size of the expansion tank. Assuming that the tank has the prescribed air cushion, the only way to reduce the pressure rise is to replace the expansion tank with a larger one.
 
  #16  
Old 11-16-09, 04:38 PM
M
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by NJ Trooper View Post
I've wrestled with that myself... isn't there also a blurb in that I&O about having a proper LWCO installed?

My normal recommendation is that unless there is an LWCO, to leave the valve open...
The B&G instructions say: "For safe boiler operation, installation of a LWCO...is recommended." But they say that the city water shutoff valve "must be kept closed except when filling the system." So that seems like B&G is saying that with or without a LWCO, the city water valve should be shut.

And here's another quote from the B&G instructions: "The PRV is designed for filling hot water boilers...to a properly controlled pressure after boiler installation or system servicing....It is not intended to be used as a water feed valve to to control boiler water...pressure."

I've referred to the PRV as an "automatic fill valve," but I guess B&G would not approve of that terminology.

Here's what Siegenthaler says about shutting the city water isolation valve: "Arguments can be made both ways. The author's opinion is that an automatic make-up valve should be turned off once all portions of the system have been in operation for about 2 weeks. This allows sufficient time for removal of the dissolved air in the system....The owner...should periodically check system pressure and turn on the make-up water system when necessary to maintain pressure."
 
  #17  
Old 11-16-09, 04:59 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
The owner...should periodically check system pressure and turn on the make-up water system when necessary to maintain pressure."
And therein lies the rub...

How many homeowners know that there's even a pressure gauge on the boiler, let alone how to read it?

Doesn't make them bad persons... but it's true.
 
  #18  
Old 11-17-09, 11:58 AM
S
Member
Join Date: Dec 2008
Location: Western Canada
Posts: 40
Received 0 Votes on 0 Posts
I've read what you have said about the pressure reducing valve attached the the city water line. Is the manual valve suppose to be open so that the PRV valve will drip water into the line if the system drops below 12-15 Psi?
 
  #19  
Old 11-17-09, 12:59 PM
M
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by skeenabilly View Post
I've read what you have said about the pressure reducing valve attached the the city water line. Is the manual valve suppose to be open so that the PRV valve will drip water into the line if the system drops below 12-15 Psi?
That would be a reason to leave the valve open.

The countervailing view is that if an undetected system leak were to go unnoticed, the open vave could keep adding water to the system, causing flood damage.

Choose your poison.
 
  #20  
Old 11-17-09, 02:21 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
causing flood damage.
At least a 'flood' happens all at once, and rarely goes unnoticed.

It's that slow.... drip ... drip ... drip ... drip ... that goes on week after week, after month, after year that is much more damaging because it could go unseen for a LONG time. I've recently seen a case where there was a leak in the plumbing under the kitchen sink. Must have been going for years, because the owner came home to a collapsed floor... rotted out the subfloor, joists, sill plate, etc... a real mess...

This can happen with a hydronic system also, and what's more, that constant influx of fresh water will cause all kinds of other problems with the heating system as well.

Best solution, install a LWCO, close the manual valve, and pay attention to the boiler pressure gauge.
 
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: