High Pressure


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Old 12-02-06, 11:57 AM
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High Pressure

I have a 24 year old Hydrotherm boiler with 2 zones in a 2 story house. I am seeing my pressure climb above 30. I know that I need to replace the pressure relief valve but I also need to determine why the pressure is high. From everything I have read in this forum I would guess that either the expansion tank or reducing valve is the cause. The expansion tank is an Extrol with an air valve at the top. Using a tire guage I have found that the pressure matches the pressure on my guage. I have tried reducing the pressure to 15 but eventually the pressure is too high again. The tank feels light so I didn't think there is water in it although I could be wrong. Also what can I do to test the reducing valve? Is there anything else that I should check as well?

Thanks
Sal
 
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Old 12-02-06, 02:39 PM
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Exp. Tank

The way to check the air pressure in the tank is to drop the boiler pressure to zero. THEN check use a tire gauge on the tank. You should have about 12#. If it is less, you can use a bicycle pump to put air into the tank. When doing so, the relief valve or other valve on the boiler should be left open.
If the air pressure on the tank is OK, the reducing (feed) valve is probably leaking thru.
 
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Old 12-02-06, 02:56 PM
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Thanks for the response Grady.

So if I reduce the boiler pressure to zero and the tank pressure is around 12 then the culprit is probably thr reducing valve. But if the tank pressure also drops to zero does that indicate a bad tank?
 
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Old 12-02-06, 03:18 PM
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Tank

Low tank pressure is usually due to the bladder in the tank being bad but once in a while it is just the air valve. If the air valve is pointed down & you don't get water when the valve core is depressed, the bladder is probably good. If the valve is up, it is harder to diagnose.
 
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Old 12-02-06, 07:22 PM
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Originally Posted by SalR
I Also what can I do to test the reducing valve?
Set the pressure to say 15PSI, and close the water supply line to the boiler. If the pressure holds, and only increases again when you open the supply line, you can be pretty sure the PRV is messin' up.

BTW Sal, those bladders can leak VERY slowly. But, if there is no water in it when you depressurize the system, it could be still OK.

Hmmm, I knew a SalR in NJ ... naaah, can't be...
 
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Old 12-03-06, 04:49 AM
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Thanks NJ Trooper...and yes it could be ....I live in Howell NJ.

Last night I had reduced the pressure to around 15 and shut the water inlet valve off and this morning after the heat had run during the night the pressure was back up to 30. Grady had said that it might be difficult to tell if the tank has a leak if the air valve is on top of the tank, which mine is. But now after seeing the pressure go back with the water off I am thinking that maybe the tank is bad. Later today after it warms up a bit I will reduce the boiler pressure to zero and see if the tank has 12 PSI.

Thanks again and thans again to you too Grady
 
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Old 12-03-06, 06:03 AM
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Tank

If you end up replacing the tank & have room, put a valve between the system & the new tank. By doing so, it makes replacing the tank the next time a whole group easier.
 
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Old 12-03-06, 10:03 AM
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Originally Posted by SalR
Thanks NJ Trooper...and yes it could be ....I live in Howell NJ.

Sal, I _DO_ know you. Sent ya a PM ...

I think yer expansion tank could be bad, take a look at this pic :

http://home.comcast.net/~jeffpicks/ET_drain.jpg

for an illustration of what Grady is talking about. The air scoop is on top, and the ET on the bottom. Pay no attention to the low pressure on the gauge. Yours will be upside down. Can you post a pic ?

=
 
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Old 12-04-06, 04:59 PM
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I replaced the tank but unfortunately there was no place to put a valve. I bled the system and pressured to 15psi. The pressure seems to be doing good. It rises when the boiler is firing but drops back to 15 when the water cools down.
The only thing is that I can hear the water running thru the pipe by the pump almost as if there is not enough water. Other than that everything seems fine.
 
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Old 12-04-06, 06:21 PM
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Running water sound

That sound is caused by air in the pipes. If you don't know how to rid your system of the air, we'll be glad to try to help. Some pictures of the boiler & nearby piping would help us help you. You can post them on photobucket or similar photo hosting site & provide a link here.
 
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Old 12-04-06, 07:53 PM
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Cool high pressure

If the water supply was shut off all night long and the boiler gauge went to 30, the tank is either bad or too small.
There is HOWEVER another culprit on occasion. If you have a hole in the domestic hot water circuit. Like a tankless hot water heater. If it only takes a few hours to see pressure rise, shut off the boiler water feed AND hot water line. If it stays steady, open the feed to the hot water line (pressureized) you'll need to replace the tankless coil if it goes up in the next few hours, sometimes this takes overnight to test. You could do it before bedtime. My moneys on the tankless coil. Remember the boiler feed is 12-15 PSIG, the domestic pressure feed is 30-55 PSIG. Pressure goes higher to lower, always! If the coil has a hole its leaking from the hot water circuit into the boiler water circuit.
 
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Old 12-06-06, 06:41 PM
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I have posted some pics
http://i132.photobucket.com/albums/q18/srappajr/boilerpics001.jpg
http://i132.photobucket.com/albums/q18/srappajr/boilerpics002.jpg
http://i132.photobucket.com/albums/q18/srappajr/boilerpics003.jpg
http://i132.photobucket.com/albums/q18/srappajr/boilerpics004.jpg
http://i132.photobucket.com/albums/q18/srappajr/boilerpics005.jpg
http://i132.photobucket.com/albums/q18/srappajr/boilerpics006.jpg

In pics 1 and 4 you can see 1 of the zone valves with the boiler drain right above it. I have 2 zones set up exactly the same.
In pic 2 I have a Grundfos circulator with the piping coming from the 2 zone valves.
When I bleed the system, I connect a hose to each of the 2 boiler drains, open the drains and lift the lever on the pressure regulator. When the water is coming out of the hoses in a steady stream (usually takes about 5 to 10 minutes), I shut the drains and pull down the regulator lever at about 15 PSI.
I don't know of anything else to do. I have a closed loop system with no bleeders.

The reason I posted pics 3, 5 and 6 was because I have to change the pressure relief valve but it appears to have a male input. Every one that I find for sale has a female inlet. It looks like it is going into an iron fitting and as you can see there is a branch that goes to the expansion tank. Do you think the current PRV has a male end or is there something else that might have been done like using a male to male nipple?

Thanks for looking..I appreciate it.
 
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Old 12-06-06, 07:37 PM
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Sal, when you say "no bleeders" , you don't even have an air scoop or automatic air vents anywhere on the system ? Can you pull back with the camera and shoot an overall shot of the system ?

On that tee leading to the expansion tank, there is a square plug. That point seems a likely place to add an auto air vent. Is there room there between the tee and the tank to install one ?

HVAC brought up a good point... is there a tankless water heater on your boiler ?

That probably is a male close nipple on the PRV.

BTW guys, a strange internet coincidence caused me to believe I did know Sal, but after a few seconds on the phone with him, I realized there could actually be TWO SalR's living in Howell, and in fact there are, cuz he ain't the guy I thought he was! (but seems like a good guy just the same!)
 
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Old 12-06-06, 08:41 PM
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Wow

It's hard to see how that thing works. Definitely pull back the camera. Hard to see the overall picture. It looks like two 3/4 pumps go to a 3/4 bullhead tee (no-no),,and thepipe is still 3/4"????is that right?
Need to see a better pic but all that loose wiring looks hodge-podge.
 
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Old 12-07-06, 03:35 PM
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HVAC, you see TWO pumps ? I only see one on the return. From what we can see in the pics, it looks like the two zone returns come together at that tee, and into the pump on the return side.

There is no view of the supply side that I can see.

The relief valve and et are on the top of the boiler, all by themselves.

I agree the wiring is... well, don't wanna hurt Sal's feelings, but frankly, it's not the best. (I have seen worse though!)
 
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Old 12-07-06, 05:47 PM
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Hi guys

I posted more pics
http://i132.photobucket.com/albums/q18/srappajr/boiler2pics001.jpg
http://i132.photobucket.com/albums/q18/srappajr/boiler2pics002.jpg
http://i132.photobucket.com/albums/q18/srappajr/boiler2pics003.jpg
http://i132.photobucket.com/albums/q18/srappajr/boiler2pics004.jpg
http://i132.photobucket.com/albums/q18/srappajr/boiler2pics005.jpg
http://i132.photobucket.com/albums/q18/srappajr/boiler2pics006.jpg
http://i132.photobucket.com/albums/q18/srappajr/boiler2pics007.jpg

At the top of pics 3 and 4 I tried to show what appears to be some kind of air escape valve but I don't know for sure what it is.
pic 7 shows the ET on the pipe next to the PRV. There is very little room and it looks like iron or galvinized pipe.

Also I do not have a tankless water heater as my hot water is separate. In fact I believe that it also shows in a few pictures.

As far as the wiring, I didn't do it so it doesn't matter to me what it looks like although I agree that it is a bit wierd. But it works!!!!

The setup is 2 zone valves going into the tee that you see which leads to 1 circulator.

Hopefully this shows enough but if you need more let me know.
Thanks again
Sal

Hey trooper...I spoke to my father and the company that he used to deal with was named Lamda but it was in north Jersey. What a coincidence.
 
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Old 12-09-06, 02:59 PM
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piping

First thing I noticed is that the back flow preventer is missing. Secondly the air vent on the top of the supply is likely no good. Vents are located on branches of a tee up on a small riser, however you need an air scoop preceeded with an 18" horizontal nipple. Get the manual from Teledyne Lars and it will show the near boiler piping diagrams required for your install. The white streeks on the back wall is likely condensate from too low a temperature. Never lower than 160F. It also looks like the gas heater flue pipe is pitched down rather than up. Back to the boiler,...The PRV, to check this , get the pressure at 12PSI and close the gate valve to the PRV. Check it again in a few days. Then open it and check in a few days. If it goes up, replace the PRV, this time with a combo PRV and back flow preventer, available @ HD.
The piping... 3/4" will handle 4GPM, (times 2=8GPM),if both zones open, you need 1" PIPING to handle 8GPM, a 3/4X3/4X1 TEE and the return line needs to continue on as 1" (8GPM) into the boiler.
 
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Old 12-15-06, 04:47 AM
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I ran the test as HVAC suggested and the pressure stayed steady. It has been warm here so the boilr hasen't cycled as much as normal but it seemded to go on and off enough to test. I looked at the Teledyne Lars manual but the piping was a lot different than mine. It showed the air scoop and ET right after the fill valve where mine is on a separate pipe coming out of the boiler which also has the relief valve. I believe that what I need to do now is replace the air vent on top of the supply and maybe add an air scoop. Does anybody know where in the system I would put that?

BTW the flue is pitched up. The look is probably related to my photographic skills.
 
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Old 12-16-06, 12:35 PM
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the air scoop

this should be as follows; a steel pipe rises about head high with a tee. A drain **** on top a 2" nipple , then a ball valve (this is for air purging in the future if needed). Then a 18" steel nipple, cast air scoop with an auto air vent on the top, a short nipple in the bottom with a tee, the side branch is where the water supply line goes. Continuing straight down ,on the same tee, you have the ET prepressurized to 12 PSIG. to the outlet of the air scoop is the circulator. Then you tee off to you two zones ...send me your email address and I shoot you a picture. I'll try to photo bucket this but who knows. http://i31.photobucket.com/albums/c373/hvac_01453/img006.jpg
 

Last edited by hvac01453; 12-16-06 at 01:22 PM. Reason: adding photo
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Old 12-17-06, 06:14 AM
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Hvac...I saw the picture and the setup is quite a bit different than what I have. I'm sure many improvements have been made over the years. I looked at my owners manual and found that my piping is correct for the time that it was installed. At this point I am not prepared to make all of the changes necessary to conform to the diagram that you showed me as it would take quite a bit of repiping. What I am going to do now is replace that air vent and rebleed the system since air is the only issue that I have now and even that seems to be minimal.

Thanks for all your help. I really appreciate it.
 
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Old 12-17-06, 07:13 AM
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Talking No big deal...

If it doesn't bother you, and the system works, don't change anything. If you get fed up with bleeding air, and the noise in the piping, then you have to make the changes. Print it out for future consideration, or in case you replace the boiler in the future... When my circulators are on, its very difficult to tell because of their silence, as are the pipes. Good Luck!
 
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Old 12-17-06, 10:06 AM
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I'm with HVAC, if it's working, and you can live with it, leave it alone.

If not, I'd rip the whole thing out and start fresh.
 
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Old 12-17-06, 01:00 PM
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I agree. HVAC: nice figure. Pumping Away, page 50. One of the most important books I've read in the past year. Solved all of my problems!
 
 

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