Are the pressures TOO high!?

JayPoorJay

Good Evening Everyone, and I am grateful you're here.

I have a general (and kind of pressing) question and am hoping for some answers. Sooner the better, lol

I had to reroute the make up water line in to my Gas Boiler today to make room for another unrelated project in the basement. The OLD line was in the way.

It's a gas boiler hot water radiator system, 2 stories/floors with 2 small pumps in the basement that moves the water thru the system. 3/4 PEX was used to replace all old hard pipe lines in the basement to first floor rads and the same PEX connects to hard pipe in the basement that delivers water UP to radiators on the second floor. Metal pipe from basement to 2nd floor.

Today, when I went to move the plumbing for the make up line I realized that the isolation valve to the make up regular valve was in the OFF position and I'm pretty sure it had been. It's set to make up water when it dips below about 17lbs.

It seems like wasn't set up to AUTO add make up water (isolation valve was in off position), but of course could be done manually when needed.

In that, I really BELIEVE that the pressures were normally running between (if I remember right) 15-20psi? and I was "comfortable" with that.

After rerouting pipes,,, I have drained water off and brought it down to the familiar 15lbs and when I get to about 15lbs the regulator will kick in and slowly add water in until it comes up to about 17lbs if I am reading the gauge right, and stops.

Then when the boiler runs it pressurizes to about 30lbs... Giving me a headache!

After the make up line pipe reroute I have left the make up isolation valve OPEN and the pressures are running higher, up to like 30psi... Because of the PEX and PEX connections, and because of the pressure change I am nervous! Should I be?

Can/should I just turn off the isolation valve to the make up water AUTO regulator and do my best to "keep an eye on things" and if the pressures drop (no auto make up water) I can just add manually to top it off? I mean, I think that's how it was before… So I guess that should be ok. No?

Im not sure what to do and would love some reassurance and advice, guidance, on how I should be thinking about this.

I THINK I would like the thing to be under 20lbs...

What to do?

BIG Thank You, in advance.

Jamie Hall

It's not your feed valve. If pressure is increasing like that when the boiler turns on, it's the expansion tank. It may have lost it's charge — or it may have failed.

First thing to try — press the Schrader valve on it. If you get air, at least the diaphragm is probably intact. Probably. Next thing is, if you can, isolate the tank and drain it. The remaining air pressure should be around 15 psig. If not, try raising it to that and leaving it a bit to see if it will hold. If not… may be time for a new tank.

mattmia2

what kind of expansion tank does it have? when was the last time it was serviced(what kind of service it needs depends on tank type)?

Does the pressure creep up with the system off? The manual valve might have been off because the pressure reducing valve is leaking so the pressure creeps up slowly with the valve on.

Have you tested the relief valve? Don't do it until you are prepared for it to not close again and you have the time and open businesses to replace it.

Since it is a 50 psig boiler 30 psig is ok but probably indicates an issue with the expansion tank, prv or a leaking water heater coil if the system has one. You can probably adjust it down to 12 psig while it is cold and turn off the pressure reducing valve or adjust the valve down to 12 psig.

JayPoorJay

Matt and Jamie!

First, thank you…

We have been running the heat all winter of course and everything has been fine - at least until today when I "fixed" something.

I am almost positive the thing was running between like 15 and 20psi...with the make up regular off...like always.

I can't here any water moving when everything is off and quiet. And, the entire system is less than 5yrs old.

I am super grateful for the advise so I definitely don't want to come off like I am disagreeing with you two,,, but I really believe my problem has to do with how I "set it up" after the work.

Will pressures go up as the SYSTEM heats up?

What about air in the system?

Can I run it to full temp, both zones, then drain off with until I am at the desired 15-20lbs?

I definitely don't want to run this thing at 30, 32, 34lns with this PEX stuff. If it was all metal, maybe, but even then.

I'm all ears, and gratitude!

JayPoorJay

This is a couple shot of the "whole" system, so you can see the bits and pieces.

mattmia2

if the prv or something else is leaking in to the system and adding water you wouldn't hear it.

does the pressure go up within a couple minutes once it starts heating and stays stable while it is cold?

pex is rated something like 80 psi at 200f.

if you made the piping smaller and created a restriction such that the prv is on the suction side of the circulator and the circulator is creating a significant pressure drop in the system then that could cause water to be pulled in through the prv.

if it only started after you opened the system then the most likely causes would be that the prv isn't holding or it has a older style compression tank without a diaphragm up in the ceiling of the boiler room and you somehow waterlogged that while draining and refilling the system. I suppose it is possible that the diaphragm was in bad shape in a diaphragm type expansion tank and the stress of removing the pressure then rep-pressurizing it caused it to rupture. also possible this has been happening for a while and you just noticed it now.

you should bring it down to about 12 psig while it is cold and turn off the manual valve and see what happens when it heats.

JayPoorJay

So,,, at the moment, I am running both zones set at 76… It's running and the psi (H2O temp is still coming up) is at the BTW 15 and 20?

Earlier, when I finished "fixing" **** and turned it on only ONE zone pump ran. That's when pressures went up. Could it have been a big old air bubble?

mattmia2

air would compress as the water expanded and keep the pressure lower. that is what the expansion tank does, just in a more controlled manner.

JayPoorJay

About the PEX... I'm not so worried that the lines will blow,,, what I do worry about (maybe irrationally) is the PEX to steel connect at each radiator will fail and blow off the nipple connection and I'll come home to a luxury basement swimming pool.

So, it's running now and the pressure crept up to just under 20 from about 17psi... I drained of a little more to about 15psi and am watching it.

When I turned on both zones I heard LOTS of air, water and bubbles moving around. When I just drained a bit of water off, lots of air bubbles and sloshing again. I feel a bit relieved,,, bit don't feel like I am out of the woods.

I feel like a jack **** now,,, winter boiler work, lol

mattmia2

if it goes to low you can have problems with things like the top of the system not heating and the circulators cavitating. going to the mid 20's is fine depending on the size of the system in relation to the expansion tank. you want at least 12 psig when the system is cold.

JayPoorJay

Got you Matt.

Thank you.

I got all panicked not without reason I think… seems like things are leveling out. House reached the 76degrees up and down stairs, pressure went to 19-20, 160degress at the boiler temp gauge. After shutting down pressure went to just above 15, boiler off.

I will definitely be keeping my eyes on it...

Thank you so much for your attention and quick replies.

I love forums!!!