Hot Topics: Water Pressure in Pipes Too High?

A boiler covered in cobwebs.

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Original Post: Water in pipes, pressure too high?

Take13Care Member

I have a couple things going on with my boiler. I’m mechanically inclined, but have zero experience with boilers and am totally willing to just pay a professional. At a minimum, I’d like to have some idea of what is happening.

So the system turns turns on with a bit of a whoosh sound. It isn’t crazy, but you can hear it. Next is this squeaking or rubbing sound (maybe pipes on a stud or expansion) followed by a sound that I originally thought was dripping, but could also be described as ticking. This is the sound that peaked my interest straight away. It's not a tick from expansion or contraction like I have heard out of a baseboard system before; this is definitely closer to a drip, but is so uniform and consistent that I just don’t think it's dripping. Also, there are no water stains to show for it. This sound had me paying closer attention to the system and I started noticing that there was serious water running through the pipes, almost as if a faucet has been turned on.

As I'm writing this, I feel as though the high pressure could be to blame. Maybe the water is meeting an elbow with pressure, causing the weird sound, followed by rushing water into the baseboards. And to continue on, the baseboard system is closed looped, I believe, as I haven’t found any bleeder valves and there are no radiators. Here's a link to some photos:

PJmax Group Moderator

So, the system is heating the home OK, but it's noisy. Correct?

Your boiler pressure is at 30 Psi. Most relief valves are rated for 30 Psi and at that point or just above it, they start letting off pressure. The device in the picture below is the relief valve. Check and see if any water is trickling out of the end. There is also a tag on the handle with its operating pressure. Your boiler is rated to 50 Psi.

A boiler.

Your system sounds like it has air in it. That's what you usually hear running through the pipes. The air gives the water a gurgling sound. That round gray tank is the pressure tank and may need to be checked for operating pressure. What would be handy to know is what the boiler pressure is when the boiler is cold. I realize with the cold weather that could be tricky to check.
Mike Speed 30 Member
According to your boiler gauge, if it is correct, the temperature is 210 degrees and the pressure is 29 Psi. Both are abnormally high. The "whoosh" you hear when the burner lights is a separate issue altogether and may be normal. I recommend that you call in a professional experienced in hot water heating to give your whole system a good going over.
Take13Care Member
I had someone come out and they said they bled the air from the system. They seemingly fixed the whoosh sound, however, the issue with the water running through the pipes only stopped for about two days. It also seems as if it’s getting worse now. I really need some help identifying possible causes so I don’t keep waking up at all hours of the night.

There is a loud running flow of water in basically all the rooms. I live in a split-level house. It also seems to be getting less efficient or having more variation in temp. It has been extremely cold and that may be the reason for that issue, but I’m mostly just trying to fix this noise issue and whatever is causing it.

Could it be that the boiler is going bad? I'm already thinking I’m going to install hot air and central ac this year, partly because I never want to deal with this again.
Also, this morning my heat stopped working and the water sound woke me up. The gauge was reading 10 Psi and 100 degrees. Water was just constantly cycling. I reset the boiler and it kicked on, thankfully. The pressure is rising (about 25 now) and the heat is as well. However, this water sound is still constant.

Steamboy Member

What type of heating units do you have? Radiators or baseboard units? What type and size of circulating pump is installed? If the heating system was recently drained, you may have to vent the air out several times over the course of the winter to get all the air out of the system. Some of the air is released when the water is heated and some is just there any time water is added to the system. You should also check the integrity of the expansion tank. There is an air fill valve on the bottom of the tank. Depress the stem (same as a car tire) to see if air or water comes out. If only air comes out, the tank is OK. According to your last post you may have to recharge the expansion tank and/or replace the auto-fill PRV. What is the BTU input and/or the output of your boiler?

Take13Care Member

Now, my unit it is turning off. I reset it, but then when it tries to fire back up it won’t turn on. I called the same place back and even though I’m a “club member” with them and have a one-year-old in a house without heat, the earliest they can do is tomorrow. So, I’m just sitting next to the boiler resetting it every time I hear it start trying to kick on.

Furd Member

What exactly are you "resetting" to get the boiler to fire again? What is the pressure in the boiler when you "reset" it? Look at the tag on the safety valve and let us know what the set pressure rating is. Do you have any idea of what the previous technician did?

lawrosa Super Moderator

I would say from the pics that your air eliminator is shot and needs to be rebuilt or replaced. Also, at 30 Psi, I would also say your expansion tank needs servicing.

As far as why the burner is not firing, a multimeter is needed for testing. It could just be the igniter.

Take13Care Member

Hopefully, I’m not about to blow myself up or anything, but I’m flipping off the switch on the side and waiting a few minutes, then turning it back on. That’s all that has got it back on for me to this point. I know I’m having an issue because if I crank the heat way up, it won’t turn on so then I “reset” it. I guess I’m not entirely sure what I am accomplishing with that, but it fires back up.

I'm under the impression that the previous guy bled the air out of the system. That’s really it. He did turn the water temp down and I turned it back up. It was at 220. He put it to 180 and I just set it to 200.

It did manage to cycle once, so I thought maybe it was better, but it has turned off twice since then and not come back on.
Also, after flipping the switch the pressure will get to about 30 Psi, but doesn’t seem to be getting to temp (200). I’m not seeing any tag that speaks to that rating other than the one reposted below.

Furd Member

In post four there is a picture of the safety valve. There should be a tag on this valve stating the set pressure. That is what I want to know. Also, look below the discharge pipe from the safety valve and see if the ground is the least bit wet, which would indicate the safety valve has been discharging.

At this point, I am leaning in the same direction as Lawrosa that your expansion tank has lost its air charge or is defective and also that the spirovent is plugged up and not releasing the air.

As for "resetting," your boiler is going into a "soft lockout." You may be able to "reset" it by simply turning the room thermostat down all the way, waiting a minute, and then raising it back to the desired room temperature. This does not cure the problem and at this point I can't even begin to diagnose why it is locking out. It could be that the unit has a high temperature lockout control and turning the aquastat control back to 180 (which should be fine) will cure that problem. Or, it could be a gas burner safety, or maybe a pressure control.

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