I recently had my Tarm boiler and 3 storage tanks out of commission for a couple days due to warm temps. After restart I went in the basement to find water on the floor. Water was coming from presure relief valve. PSI was at almost 30 and the water was not even that hot. This morning the pressure was 22 with no fire going for 2 days. Whats up with that? I ran all winter without the pressure going over 23ish. How much pressure should I have with water tanks at room temperature? Does anyone know why I have so much psi?
TOO MUCH PRESSURE
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First you could shut off the cold water supply to check the fill valve for malfunction after bleeding some pressure off. See if it stays the same. One thing making pressure during shutdown would be the fill valve. There is a way to adjust it for different pressure. Loosen jamb nut and turn out lever. My guess is the fill valve unless you have a domestic coil in the boiler water jacket.Fill valves can get deposits which will affect their operation. If a domestic coil is there it could have a pin hole or better leak causing excess pressure. This is another option. To determine if it is the coil, shut down the supply to the coil and see how the pressure fairs. Others will chime in but this is a start point.
Will
Will
afblue
Feeling the Heat
do you keep gaining water pressure, or are you blowing as you heat up the system? A water logged expansion tank, could be a possibility, or if you set your pressure when everything was hot, then you cooled down and your fill valve let water in, you have too much water in the system. The system pressure should be 12PSI when hot.
woodsmaster
Minister of Fire
afblue said:
Most fill valves set the pressure at 12 or 13 cold so your pressure should be that cold and not over 32 or whatever your relief valve is at at full temp. It should be more than 12 when hot
afblue
Feeling the Heat
Yes that is true provided the expansion tank is sized correctly for the given volume of the pressurized storage tanks. If it is undersized or water logged, the system when it cools down to room temp it will call for more water from the fill valve. Then when the system is heated back up and the large volume of water expands it will max out the expansion tank then eventually blow the relief valve. If the system sits with all the valves open and steady state, and the boiler not heated and the pressure is rising, its most likely a fault of a leaking DHW coil or similar system.woodsmaster said:
Willman let me restate,I am not building pressure while shutdown. The pressure builds as soon as I make a fire. The pressure in the system was 20 psi this morning with cold tanks and rose to 30 as soon as hot water started filling the tanks. I ran the system the entire winter with no problems. I dont know much about fill valves but I noticed a flat screw head on top of the caleffi valve. What should this screw be set at? I drained about 40 gallons of water out of the system with the fill valve closed and the psi went down to about 15psi. At that point it felt like the expansion tank was empty. There is also a turn knob on the bottom,but I dont know what it does. I tried calling my plumber without any call back. I dont have a domestic coil.
afblue and woodmaster, If my expansion tank was water logged, and i dont have a domestic coil what will happen when I open the fill valve back up? I guess well see.
afblue and woodmaster, If my expansion tank was water logged, and i dont have a domestic coil what will happen when I open the fill valve back up? I guess well see.
It sounds to me like the fill valve is at fault. If it is set too high, then when your system cooled, it added water. Next you added heat and then the pressure went up. Try closing the fill valve, bleed off pressure to ~12psi. Open the fill valve. The pressure should not rise above 15 psi, if so then you need to adjust the fill valve. To do this, turn off the fill valve, bleed off system again to 12 psi, loosen the screw on the fill valve. Open the fill valve and close screw until 15 psi reached. I'm not sure how old the fill valve is, but it may require replacement. A big NOTE here, do this on a cold system, as addding cold/cool water can cause problems with your boiler, depending on how it is plumbed.
Fred61
Minister of Fire
Squeezle Bob said:
Why turn it back on? Establish 15 psi cold, leave it off and fire up the unit. I don't have mine on. I do monitor the pressure when firing the boiler. If you don't have leaks, there is no reason to have it on. These aren't like a fossil boiler that only gets looked at once in six months or a year. There's someone standing in front of it at least every other day or even more frequently.
I agree with Fred.
I would close the feed valve, drain the system to reach 12-13 psi, fire the unit up to temp and see if the pressure stays within a normal range.
If the pressure does not go out of range it's the fill valve.
If the pressure goes out of range, it's the expansion tank.
I would close the feed valve, drain the system to reach 12-13 psi, fire the unit up to temp and see if the pressure stays within a normal range.
If the pressure does not go out of range it's the fill valve.
If the pressure goes out of range, it's the expansion tank.
woodsmaster
Minister of Fire
If you are going to shut the fill valve off for extended periods of time you should have a low water cut off installed.
Fred61
Minister of Fire
woodsmaster said:
I don't have a low water cut off. Make-up water valve has been off all winter. I'll expect a sympathy card from you when she melts down. Seriously though, the pressure guage has not changed significantly at a given temperature all season. It moves up a couple lbs from cold to 180 degrees.
afblue
Feeling the Heat
A low water cut off is a good idea in a system that doesnt have storage, but something tell me you are going to have alot bigger issue if you loose 1000 gals of water, thats going to be alot more of an indication than the low water cut off doing anything
Do you have a modern x tank (bladder type) or an old school tank mounted at ceiling.Either could be waterlogged.
Will
jebatty
Minister of Fire
I guess I'm in the worst of all worlds - no fill valve, no low water cut-off, no water supply in my shop, 250' of hose from house to shop to add water to boiler system, if needed. The only time water was needed was when I first filled the system.
woodsmaster
Minister of Fire
I don't have a cut -off on mine yet or water to the fill valve yet either.( plan on hooking up the water line soon) Just didn't want someone to get that addvise then have a meltdown not Knowing the risks.
Mine stays at about 40 psi. I told the installer and he said that is plenty. I hope it ain't too plenty. I have a valve that is supposed to reduce the pressure but not sure it works.
afblue
Feeling the Heat
ihookem said:
Your system pressure is at 40psi? There is supposed to be a pressure relief valve that prevents the system from going above 30PSI. The max working pressure for EKO and PAXO boilers is only 25PSI.
woodsmaster
Minister of Fire
afblue said:
You dont have to loose the 1000 gallon of water for a melt down. an air pocket at the pump could do you in. I agree not likly ,but could happen.
I have a valve that is supposed to make it so it doesn't do that. I didn't know the EKO was only supposed to be at 25 psi. I have a plumber who does lots of hydronics I will ask him to come over and look at it. It was @ 50 today, I drained 2 gallons out and dropped to 25. My plumber said the pressure regulator is bad if it is that high. Sometimes they are a little off but not that bad.
afblue
Feeling the Heat
ihookem said:
The main concern is where is your Boiler Pressure Relief valve? That should be popping off pressure and keeping your system from pressurizing over 30 Psi. I am confident that the EKO and PAXO design will no be affected by a little over pressure like that, I am sure they are factory tested to way over 100-150PSI, but on a safety standpoint, if a pipe ruptures or a compression fitting lets loose, its extremely dangerous.
Thanks boyz, that was the problem. Pressure tank was water logged. Drained 30 gallons,cleaned fill valve and set it to 15 psi. Beer time.
I agree. I don't think your pressure relief valve is working or is the wrong type. I would replace it or even better add another one. Have you ever seen the vid of the water heater with out a relief valve. It blasts out the top of the house and out of sight. Lots of old timer died when the old steam engines blew.afblue said:
Heard of an amish neighbor that had a 4000gal 1/2 in thick tank being used for an air tank. He was running it with a gas compressor setup with out a relief valve. They would run it for a while and shut it off. Got busy and forgot. luckily it was out side. Blew the top off and split the side and it landed half way inside thru the cement wall. No one was hurt but if it had been inside the building it would have made toothpicks. I can't even imagine releasing that much volume of air inside a building like that.
Remember, water at pressure makes steam at higher pressure. If you break a pipe and lower the pressure fast that super heated water goes to steam immediately and expands to make a HOT bomb.
Relief valves are your friend.
leaddog
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