Heating, Air Conditioning, Fridge, HVAC/Boiler heat


Mike here's My problem. I have what lookes like the brand name is Emerald oil fired hot water boiler. With a Beckett RWB burner. I can't find the problem why the pressure valve keeps opening and spraying the floor every so often maybe once a week.  First thing I replaced was the expansion tank last year it was really rusty.  I though it was a bad pressure regulator. Changed it out with a new Watts 156f regulator 10 to 25 lbs. Setting new valve was not set so I screwed the lever out untill the water pressure at the boiler was @ 20lbs. Didn't change a thing with the overflow prob. Then I changed out the Pressure relief valve with a Watts model M. 15 to  30 lbs. Same prob. Then changed the water tem. settings @ 180 high 160 low diff 15 still same prob. Changed out the thermostat with a new Honeywell. I have blead it out the air every time I changed a part. Every once in a while the pipes will bang very slightly. It only bursts about aquart of water @ a time. I hade the furnace serviced about a year ago give or take 6 months. Also I pulled the cover off and cleaned and vacumed out the heat excange tubes while I was right there anyway. I am a ASE Master Auto tec just saying that I am Very good @ solving prob. Not bragging though!! I have experiance with plumbing, wiring and hot air furnaces. This has really got me stumped??? Also the furnace seems to cycle appropriatly. I live in Maine long winter.  Any suggestions will be greatly apreciated. Hope I didn't over loaded You with to much usless info. I don't Know where to go from here. Please help.
         Thank You,
         Brian Hall

A boiler is pressurized to offset the effect of the static weight of the water upon itself.  So you take the height of the building from the base of the boiler to the top radiator and divide by 2.31   This is your fill pressure required.  Fill pressure is initially set with the boiler water cold.

Your automatic fill valve and your bladder-type expansion tank come from the factory set at 12 psi.  Use this pressure if the fill pressure you arrived at is 10 psi or less.  Adjust both the tank and the fill valve to the same pressure if you need more than 12 psi.  Use a bicycle-type pressure gauge to check the tank.  The tank pressure is only set accurately when the system pressure is at 0 psi--or the tank is removed off the system.

If this is a Columbia Emerald Boiler than on page 6 of the install guide it shows where you install the bladder tank and the air purger on the boiler.  See the bladder-tank manufacturers instructions to determine the correct capacity (size) tank for your system.

If you use the boiler to make hot water for the residence then it is possible that the coil inside this boiler is leaking into the boiler water.  This will cause it to relieve pressure out of the relief valve.  The only fix is a new coil for this failure.

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Mike Reavis


Questions related to "Wet Heat". This is heating your home, office etc. with radiators, panels, and convector apparatus. Steam and water heat. I can answer questions about boilers, piping,and associated parts of these systems. Please do not ask for specific information about how I feel about one boiler, etc. over another--These questions should be directed to a licensed contractor that you know of, or that your neighbors and colleagues look to to provide solutions.


I have 20 plus years experience, which has lead to passing my state master HVAC license.


Completed college

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I work on the manufacturer's side of the business currently

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