Aquastat control problem/situation

Old 10-25-09, 09:47 PM
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Aquastat control problem/situation

I have (or had) boiler with DHW heater. Past April, when I bought the property, I 'detached' DHW heating system from the boiler after installing electric water heater. Now, the cold weather being near, the boiler would not heat up, or continue running. Currently, Low limit is set to 160, High limit is set to 180, diferential is set to 20 on Aquatat. When I turned up the thermostat(calling for heat) and press the reset button, the burner will be on for about 15 minutes and turns itself off and won't turn on unless I press reset button again. The circulator appears to be working because I hear 'humming' noise and water running noise after the burner is off. Can anyone share with experience(s) as to how I can 'fix' this boiler/situation? FYI, I have Columbia Boiler with Beckett AFG oil burner (Model EM-110), Honeywell R8182D.
Old 10-26-09, 02:35 PM
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First thing, since you are no longer using the boiler for domestic hot water, you can save a bunch of fuel by turning the LOW limit all the way down... I think that's like 120 or so... and the DIFF could go to like 15... those settings are the ones that keep the boiler warm for the domestic hot water. The HIGH setting is the high limit for the heating circuit.

Have you had the system serviced? It's important for an oil burner to be serviced each year. The chamber and heat exchanger should be brushed and vacuumed, the oil filter should be changed, the nozzle should be replaced, electrodes adjusted and the tech should do some combustion testing.

That's the first thing to do if it hasn't been done in who knows how long.

DO NOT keep pressing the reset button. What can happen is that if the burner doesn't fire up, you can end up with a bunch of unburned fuel in the chamber and that's not a good thing!

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