Boiler cycles on and off rapidly......

Old 12-07-04, 01:48 PM
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Boiler cycles on and off rapidly......

My old house has a Kohler "22" oil-fired boiler serving four dissimilar-sized zones. Recently I have noticed that the boiler is cycling on, running for less than two minutes, then turning off again, only to repeat the process five or six minutes later. This occurs even though none of the zones are demanding any heat.

There are two thermostatic devices on the boiler. One is a large, old-fashioned looking thing hanging directly on the back of the boiler near the top, apparently reading the temp of the water inside. The second is a much slimmer, more modern looking upright affair that is attached to the back of the unused old domestic hot water coil that hangs off the back of the beast.

I experimented with the temp control on this second device and found that turning the selector down towards 170 from the 180 it was set at immediately turned off the boiler, but I don't think that this is a good practice to follow unadvisedly. I have not tried changing the setting on the device directly attached to the boiler itself.

If anyone can shed some light on a proper approach to this situation I would be most grateful. I apologize in advance if this is a redundant question....I searched the forum but could not find any similar topic. Perhaps I did not form my query correctly?
Old 12-08-04, 09:45 AM
Ed Imeduc's Avatar
Join Date: Aug 2002
Location: Mountain Williams Missouri
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You have to find out what controls what there. most of the time boilers are set for on at 160o and off at 180o. I think Id go for the big old one in the back can you see when it kicks on and off. If it is of the immersion type can be the tube its in need cleaning are its element needs cleaning. Can it be the oil burner? you did have it serviced this year??
Do you know how its wired? most of the time the boiler runs by itself to keep the water hot. the tstat just turn the pumps on.Could be the motor on it thats about the only way it could go on and off and not make it so you have to hit the reset.
Come on back to the same post here if you need more help.


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