"alt-hvac Moderated" wrote in message
...
Dear Turtle,
After reading your lengthy piece on three wire defrost systems, I'm OK
with the concept of cumulative run. However, I could make no sense out of
much of what you said. Something about when the unit is in defrost it
sends
power out to the neutral through the defrost timer (which I'm OK with
that)
and somehow that advances the timer off the neutral (huh?).

"It will have only 3 wires run to the defrost timer and will have the
defrost
timer wire [2] run from the run over to the defrost element and if the
timer
is in run. It will send power through the timer motor and on to netural
out
through the defrost element. then when it is in defrost. It will send
power
through the defrost timer motor to netural out through the compressor
circuit. Wired this way it will only log time of the 6 hours of defrost
time
and only go into defrost ever 6 hours of the compressor run time and can
go
into defrost as long as 2 days before getting 6 hours of run time"

So, you're saying that the defrost timer neutral goes though the defrost
element? That's fine, cause it's only a watt or two. Won't even see the
heater element. Unless it has a terminator element (bimetal) and then the
run time will be only when the evap is cold. And when it's in defrost,
that
the timer neutral goes though the compressor? Should oughta do that OK,
it's
only trying to drain off a watt or two. Won't even see any resistance in
the
compressor. Still, it seems easier to just neutral the timer and be done
with it.


I decided for curiosity to go back to the original post. And what I
found was that the original customer's request sounds like a bad defrost
heater element, since it shuts down and thawing helps shorten the recovery
time.

--

Christopher A. Young

This is Turtle.

You still missed it. If the defrost element was burnt up and broke the
circuit from the defrost terminal through the element to the netural the
defrost timer would never advance another minute. It will never come back on
at all , defrost that is. He said in the original post it was a intermitten
problem and would run sometime and just stop for a while or day and go back
to working. So with the defrost element burnt. The refrigerator defrost
timer would stop running when it got into run mode and never go into defrost
again. It would run all the time and never go into defrost again for it
would be stuck in run all the time. You would never see it cut off after it
froze up and just keep running.

TURTLE