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Hookemdevils22 01-15-2013 11:14 AM

Trane XE1000 Troubleshooting Lack of Heat
I've got a pair of Trane XE1000 split heat pumps, PN TWR036B100A0, that I need help troubleshooting. The outside unit for the upstairs is not running. I've set the thermostat to both heat and AC, and the outside pump clicks each time, suggesting the relay (contactor?) works; however, neither the fan nor the compressor start.

My multimeter does not have a capacitance check, so I can't check the capacitors, but the HVAC inspection did note a bad run capacitor. The fan was replaced in the past with an Emerson 1/3 hp unit, PN K55HXTKN-9183. I also noticed that the downstairs pump (which is running perfectly fine right now) has a Kickstart TO-5 hard start device, though the upstairs does not.

I have the service documentation for reference (can't attach - it's too large). Trane calls for 5uF/370v and 55uF/440v capacitors, and a GE 97F9001 (oval, 7.5uF/370v/60Hz) and Aerovox Z26P4455M (round, 55uf/440v/60Hz) are installed.

Edit: I've uploaded the docs to Google. Click here.

Hookemdevils22 01-17-2013 12:36 PM

Nobody? Bueller? Bueller?

I've got a capacitance tester on order. Will update with my troubleshooting. I'm thinking/hoping it is the start capacitor. Looking at the schematic (rez kind of blurs out the wording), it appears that start kit BAYKSKT250 may be to blame, as it leads to both the fan and compressor.

beenthere 01-17-2013 05:41 PM

Start capacitor would have no effect on the fan. make sure you are getting 240 volts to the contactor. An that you are getting 240 volts out of the contactor.

Hookemdevils22 01-17-2013 08:48 PM

Awesome, thanks for the response. I checked the contactor, and wasn't getting voltage initially. The breaker had been tripped - I believe I must have tripped it when I cut power to parts of the house while doing some wiring.

The compressor now kicks on, but the fan does not. I checked voltage to the capacitor, and it is good. The black 'R' wire from the n/c relay also has voltage when the system is not powered (I admittedly did not check it under power). That leaves the capacitor, fan motor and wiring. I will check the capacitor when I get the capacitance checker.

REP 01-18-2013 01:17 AM

Just so you know,the capsitor is matched to the motor in use which would explain the diff between the 5 and the 7.5 cap you have.It usually says on the motor what size cap to use.If you wait until you get the cap checker,a lot of people use 10 percent differance as the cut off between good and bad.I always used 5 percent with the thinking that if it has degraded at all it will continue to degrade and that would be another call to me for a cheap (usually around $7.50 for cap) part.jusdt a thought!!!

hvactech126 01-18-2013 06:35 AM

I can't tell for sure, do you have power to the motor? Test point would be at the defrost control relay (black wire) and at the contactor (red wire).

Hookemdevils22 01-18-2013 10:09 AM

I looked up the fan motor, and it indeed uses a 7.5 uF cap - thus the difference.

hvac, I haven't checked at the motor, but the wiring in the control panel has power - the black has power at rest (n/c relay), while the red has power when the system is switched on. I didn't think to check the n/c relay and black wire with the system on.

Hookemdevils22 01-23-2013 11:52 PM

Well, the fan cap was outside spec (6.4 uF vs. rated at 7.5), but the fan appears to be toast. I pulled the fan assembly and checked to make sure it had voltage (which it did) and was wired correctly (which it was according to the diagram on the fan itself). Looks like it's time for a new outside fan. Luckily it's no longer 'extremely cold' here (aka 40s at night and 60s during the day), so the HP is unnecessary.

FYI, the fan wiring is black to n/c relay, white to contactor, and brown and brown/white to capacitor (with a capped red wire for low-speed operation - which, now that I think about it, I should have hooked up and tried...). Question - is the n/c relay for defrost? Because it currently has power.

beenthere 01-24-2013 04:43 AM

Yep, defrost relay's fan relay is N.C.

Hookemdevils22 01-24-2013 05:56 AM

wonderful. Thanks for the help everyone - you guys have been awesome. Much appreciated.

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