I've had this pressured wood boiler system for 4 years now and it has been working great. This year when I started it up I had a problem with the system not circulating the heated water. The wood boiler showed 185 degrees, but the line 3 feet from the boiler and in my house were cold. I found my air bleed was plugged and I had air in the system. Now it heats up to 185 degrees and circulates the heated water fine, but my system pressure is 15psi at 185 degrees (just where I want to be), but drops to only about 1psi at 170 degrees. This is the temp that my aquastat opens the damper and starts the blower fan. Previous years the system would only have a couple psi change from 185 to 170 degree. I'm wondering if my expansion tank is not working properly? Why else would the pressure drop with such a small temperature change?
Pressured system problem
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Sounds like a leak in the system. Will it hold a steady pressure without firing the boiler? Fill it to 20 psi and let it sit overnight. It should be the same in the morning if the temperature has stayed about the same.
Push the tire stem valve in on the expansion tank, if water comes out the bladder has failed.
hr
Push the tire stem valve in on the expansion tank, if water comes out the bladder has failed.
hr
The system is up and running now. So I can't test it has you explained. If I had a leak, wouldn't I totally loose pressure and have to add water to the system. Its been operating for a month like this and I've not had to add water. I'll go out and check the expansion tank. Thanks
The air bleed that was plugged, could it have a small leak? Enough of a leak to lower the pressure but not enough of a leak to require adding water. The static water pressure test will tell you.
hr
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NATE379 said:
I don't know how do you check it and what should it be? I did go out and quick push the schrader valve on the bottom and all that came out was very stinky air.
Im not positive about all of this, but this is my understanding of expansion tanks.
The expansion tanks are precharged with lets guess about 12PSI of air....when empty or "off line" (new in box).
They have a rubberized bladder in them to keep the water on one side, and the "pre-charge" air on the other.
Sometimes when they fail, the bladder can perforate, or rip, which allows the air from the 12psi side to go into your boiler system, and then you would get a "hydraulic" effect, where there is no room for the heating water to expand into, especially if you have an autovent, or you burp your system.
You will most likely have to isolate the tank, and remove it from your system, or drain your system sufficiently to allow you to take it off, and check the air pressure precharge on the schraeder. If you pump it up, and the air is seen/heard escaping from the water side, then the bladder is ruptured and the tank is junk. If it's just flat (no or little air) check your schraeder for a slow leak with some snoop (bubble solution) after properly airing it back up. You may be able to tighten the schraeder slightly.
if it's none of these, I appologize for the "Goose chase" in advance.
The expansion tanks are precharged with lets guess about 12PSI of air....when empty or "off line" (new in box).
They have a rubberized bladder in them to keep the water on one side, and the "pre-charge" air on the other.
Sometimes when they fail, the bladder can perforate, or rip, which allows the air from the 12psi side to go into your boiler system, and then you would get a "hydraulic" effect, where there is no room for the heating water to expand into, especially if you have an autovent, or you burp your system.
You will most likely have to isolate the tank, and remove it from your system, or drain your system sufficiently to allow you to take it off, and check the air pressure precharge on the schraeder. If you pump it up, and the air is seen/heard escaping from the water side, then the bladder is ruptured and the tank is junk. If it's just flat (no or little air) check your schraeder for a slow leak with some snoop (bubble solution) after properly airing it back up. You may be able to tighten the schraeder slightly.
if it's none of these, I appologize for the "Goose chase" in advance.
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