I have a Trane XL1400 3 ton heatpump. The breaker for the outdoor unit
instantly trips and this is with the air conditioning thermostat set to off,
so my problem lies on the line side of the contactor, L1 and L2. I have the
wiring schematics for my unit and I discovered that if I detach the wire
going from either L1 or L2 to the sump heater that the breaker will no
longer trip. What I need to know is if the sump heater is something that is
separate from the compressor and can be replaced without disturbing the it.
I'm fairly knowledgeable about electronics and electrical wiring but know
absolutely nothing about the freon side of an air conditioner.
The sump heater can be replaced. If it is a scroll compressor, it is a
band type around the outside of the compressor near the bottom of it. If
it is a recip, it is in a well on the underside of the compressor.
Failures of the sump heaters are not that uncommon, and are usually a
fairly simple repair, though the ones on the recips can be a bitch to
get to. It would be a good idea to replace the thermostat that controls
the sump heater at the same time. Larry
Larry, thanks for the info. Can you tell me how in the world I can get
access to the compressor and sump heater. This Trane XL1400 looks like a
large box, seems to be surrounded on slightly over 3 sides with the aluminum
coils. 2 side panels come off, one revealing all the electrical connections
and controls along with the transfer valve. The opposite side comes off
also but behind it was just more cooling fins. It almost looks like you
have to go in through the top but for the life of me I can't figure out how
to take the large cover off the top of the unit.
Paul, thanks, I will look for the screws. I suspect that I might be able to
get to the heater after taking the fan off the top. Looks like I might need
some sky hooks to suspend myself upside-down while I try and reach the
bottom of the compressor.
I hope the smiley face that went with the "Take the compressor out" meant
what I think it means.
Thus the need for a monkey. A very small one. That's handy
One place I worked, we used to keep a really really small guy
on staff for such things. We would hang him by his feet and lower him
into the unit. Then one day he slipped, and we couldn't get him out.
So we put the cover back on and left.
Depends how much you like taking compressors out :-)
Click here every day to feed an animal that needs you today !!!
Considering I know absolutely nothing about the compressor side of an
airconditioner I think I'll try it the hard way first. What I'm wondering
is if the unit would work without the sump heater. Reading a article from
Trane, they state this about the sump heater:
"This device is designed to warm the compressor crankcase or sump, in order
to prevent or deter refrigerant migration during the compressor off cycle.
Compressor crankcase heaters are required for low ambient cooling
I live in Tampa Florida and right now the ambient temp is anything but low.
Barely makes it into the upper 70's by morning with highs around 90+. Might
it work without the sump heater?
Jerry, the unit will work fine for now with the heater disconnected. I'd
replace it before winter though. On most of the XL Tranes, there are
four clips that hold the top cover on. You push the cover down slightly
and pull the bottom edge out slightly at the ame time. If you have
someone to help you, it makes it a lot easier. Otherwise, you will get
one side loose and then when you try to do the other side, the first
side locks back into place. Larry
Thanks Larry, I may just try and take a look at the compressor with the top
off and see what I'm in for with replacing the sump heater. It's a bitch
working outside on that unit when It's 90 and the sun is beating down on
you. A job that would be easier if left for November.
I think what you're referring to is the crankcase heater.
The heater is on whenever there is power on the condensing
unit. There are two types you will see on HVAC compressors.
One looks like a long screw type hose clamp that wraps around
the lower part of the compressor and the other is a ceramic
cartridge that slips into a well in the side of the lower
crankcase of the compressor. The ceramic heater will be coated
with a heat transfer compound that resembles white grease
and held in place with an internal spring clip. If either type
heater is shorted somehow, it will trip the circuit breaker.
The heaters are easily replaced without disturbing the hermetic
system. There are some heater systems that apply a limited
current to the motor windings to keep the compressor warm but
I haven't seen it on a home HVAC system.
Educate me, what brands? I'd like to know so
I don't break one. Some years ago, a friend
asked me to check out a system he had just
installed because he thought something was wrong
with it. I thought something was wrong too
until I read the documentation and spoke with
the distributer. I had no experience with the
electronically controlled blower motors at the
time and had to be educated. I started repairing
AC units back in the early 1970's and have seen
a lot of changes since then. The modern equipment
is like a new toy for me when I discover how they
Rheem/RUUD, most Carrier/Bryant/Payne, as well as most ICP products. when
you open one up that still has the *ORIGINAL* contactor, you will probaly
find that it has a single pole contactor with a shunt. FWIW, *MOST* scroll
compressors use the start windings for CCH.
Thanks, I hadn't really noticed it on the wiring diagrams.
In truth, I haven't had to replace that many scroll
compressors. Tomorrow I have to help a friend, who I do
a lot of HVAC work with, change out a 1.5 ton recip. I
will look for the circuit now and be careful to make sure
the crankcase heat is on for any of the scroll compressors
I come across. And I thought the manufacturers were just
being cheap with that single contact.
First off I would like to thank Larry, Paul, Steve, The Daring Dufas and
That One for taking the time to help me with my problem. I decided for now
take Larry's advice and just turn the unit on because with the hot weather
the heater wouldn't be needed. I did and it works just fine, I guess I'll
put off the repair until the fall when it's a little cooler down here in
I did discover that I had the parts list for the unit all the time, it came
with the units documentation and the sump heater (part # HTR1298) is the
cigar shaped type. The settings of the thermostat that controls the heater
(part # THT0811) has settings that I would not have expected, closed at 73
and open at 105. I would have thought they would have been much lower but
they are what they are and I'll probably replace it also. If removing the
original sump heater proves to be more than I can handle I may consider one
of the aftermarket wrap around type heaters, it may be easier to install.
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