All my life I have lived in home heated with oil and hot water
We recently moved and live in a house that has oil heat and forced hot
My question is when heat is called for the air is blown out of the
vents for very short periods of time, maybe 15-20 seconds) It then
shuts off and maybe 20 seconds later it starts again. It repeats this
on-off cycle until heat is no longer called for. The time the blower
stays on seem to increase slihtly as the number of on-off cycles
My question -- Is this normal???
My thermostat has the capability of forcing the blower to stay on for
an extra 90 seconds after call for heat ends. Should I use this
setting or is what is happening now normal?
No, that's not normal-- the heat cycle should be much longer. It sounds like
it needs an adjustment.
And I would let the fan run after the burner stops. There's still heat in
the system and you might as well have it blow into the house instead of
dissipate up the chimney.
There are two switch settings on the furnace hot air plenum that
control this. One sets the temp when the blower turns on, the other
sets the temp when the blower turns off. The turn on is set higher
than the turn off. That way, the first air to come out is nice and
warm. The turn off is lower, so that after the burner shuts off, it
keeps air moving to get just about all the heat out of the furnace.
Sounds like yous are set incorrectly. My furnace will do the on/off
action your describing if the house is very cold, like 40 degrees and
the furnace is turned on. It occurs then because the air is so cold,
that after the blower starts, the cold incoming air drops the air temp
in the hot air penum below the shut off temp. After awhile, as the
temp rises, it starts behaving normally. Under normal conditions, the
burner should come on, then a couple mins later the blower, then after
15 mins or so the burner shuts off, then a few mins later the blower
shuts off, completing the cycle.
No it is not normal.
The fan control on the furnace MAY need adjustment. It could also be other
issues with the furnace itself causing the fan to cycle. The fan control
senses heat from the heat exchanger and runs as needed. Yours may need
replacement, or adjustment, or some other problem.
Get the furnace looked over by a GOOD oil man.
Oil furnaces are typically ignored until something stops them from running.
Most people do not realize that oil burners take more service than gas
systems to keep running properly. Your furnace may need just a simple
adjustment, or perhaps a through cleaning.
I wouldn't fiddle with this adjustment until the other stuff is
working. I think this is only to keep the fan on *after* the burner
stops, and you don't say but I think your burner is also stopping, not
just the fan.
After the other stufff is working, it will probably not be necessariy
to change this.
If the previous owner knew he was moving and the furnace was giving
small problems, he might not have called anyone. But You should have
a service call anyhow to tell you what all you need to know. Tell him
about this problem of course.
He'll want to sell you a contract. I really don't know if those are a
good deal. One oil company impolied they wouldn't put me on
autmatic delivery unless I got the maintenance contract, but they did.
After all, if they don't come automatically, a customerI might call
Remove NOPSAM to email me. Please let
me know if you have posted also.
this is Turtle.
this short cycling is no where near right and you need to have a good oil
furnace man look at it. i can think of 8 reason that could be wrong with it and
maybe more if i really think about it. Also It is costing you money by heating
with it short cycling condition.
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