burnham furnace

Old 05-09-10, 01:06 PM
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burnham furnace

I have a burnham furnace rs109 , I had to change the 30 lb relief valve . I found it was leaking. The water pressure was over 22 lbs , I was told its only supposed to be 11-15 lbs. When I bled the zones the pressure dropped to 12 lbs. any reason for the pressure to get so high.
Old 05-09-10, 01:18 PM
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Three main reasons for high pressure...

1. Expansion tank needs service. If the expansion tank is the problem, it usually will show up as the pressure builds fairly quickly AS THE BOILER IS HEATING UP. The relief valve usually will leak when the water gets hot, and then as it cools, the pressure will drop again.

2. The automatic fill valve is leaking through. This usually shows up as a SLOWLY increasing pressure over time... days/weeks. (sometimes hours...)

3. IF your boiler has a coil inside it that makes domestic hot water, that coil can leak and overpressure the system.

My bet is #1 - there are two types of tanks, the smaller newer kind that looks like a propane tank from a gas grill and hangs from the piping, or the older style larger steel tank that is strapped into the joists above the boiler. The service instructions for each are very different. Which type do you have?

You can test for the #2 condition pretty easily. When the boiler is cold, and the pressure is at 12 PSI, CLOSE the MANUAL shutoff valve ahead of the automatic one. Run the system for a while and watch the pressure gauge.

BEWARE of faulty pressure gauges on the boiler! They are OFTEN defective.

There are TONS of other posts here on this forum dealing with this problem. Please use the search function to look for them.

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