Carrier 30RBC AquaSnap alarm A2.01

[mesahvac]

Carrier AquaSnap m#30RBC1206-BH40-L
I’m getting a A2.01 alarm high motor temperature in compressor. Determined sensor is bad but compressor is still good. If this happens what do you guys usually do? Remove sensor and fake out on scroll protection module or replace with some type external sensor? Thanks for any insight guys

[chillrdude]

Is it a 25 ton Danfoss scroll? are you sure the sensor is bad or is the motor really getting hot? the 25 ton Danfoss scrolls have been shit as far as I'm concerned, I think I've read on here of other guys having problems as well. You can put a resistor across the sensor input on the SPM and see what happens, my money says it burns up.

[mesahvac]

Is it a 25 ton Danfoss scroll? are you sure the sensor is bad or is the motor really getting hot? the 25 ton Danfoss scrolls have been shit as far as I'm concerned, I think I've read on here of other guys having problems as well. You can put a resistor across the sensor input on the SPM and see what happens, my money says it burns up.

Circuit was locked out two compressor tandem circuit. Both ambient temperature. Cleared alarm and came right back. Resistance reading on sensor was above 4.5k ohms can’t remember exactly. Compressor ohms out good didn’t try starting circuit. Just wondering if anyone seen these internal PTC motor temp sensors fail. Would hate to replace whole compressor if just sensor is bad. Wondering what options I had and yes it is the blue danfoss compressor.

[chillrdude]

Do you have NSTV ? if so you could read the motor temps in real time, in the pics below Circuit A comp A was having a problem, at start up the ohm reading would be normal at 270ish within about 45 seconds of run time the motor temp sensor would be at 5k and shut off, customer wanted me to bypass the sensor, it burned up pretty quick.

[mesahvac]

Chillrdude,
Appreciate the help. On your situation was compressor good and just sensor going out of range after some runtime? If so did you replace compressor or end up bypassing sensor of some sort? I’m heading back out Monday gonna bring a resistor and try to bypass and see if I can run compressor to verify comp and SPM are good.

[chillrdude]

The winding sensor was good and doing what it was supposed to, the motor was actually getting to hot, customer thought maybe the sensor was not working properly and wanted to try and bypass the sensor, it burnt up pretty quick as I recall. This particular chiller is a 210 ton unit with 3 circuits, circuits A & C are 3 25 ton Danfoss scrolls, circuit B is 3 20 ton Danfoss scrolls, it's a little over 5 years old and I've already replaced 5 or 6 of the 25 ton compressors, circuit B with the 20 ton scrolls has been great.

[mesahvac]

Similar issue here. We just picked up this machine in the summer has had both A1 and A2 comps replaced by previous company. About a month ago B1 compressor failed and running B2 and B3. We quoted them to replace B1 which we have to shutdown circuit to repair. Now with this A2.01 alarm we gotta fix this issue before we can take b circuit down. Only reason I’m thinking it’s not comp issue is cause it checks good electrically and is not hot to the touch. If sensor was working ohm value would fall below the 4.5k. I will try and run Monday and see what happens keep you posted. Thanks for all the help.

[Buka]

It feels like you have a short circuit. Compare the inductance of the windings of a normal compressor and a dying one.

[ritchie001]

Mesahvac. I'm having similar issues with a Carrier 30RBC. What was the outcome of this. Did you condemn the compressor or was it the sensor?

[gonefsihing]

Had that error on similar compressor. Was a bad contactor only putting 165 volts on 1 leg on 208/3. All t contactor were shot and replaced. Have not had an issue since 3 years later.

[Cool breeze 38]

when changing compressors in a multi compressor refrigerant circuit. Be sure to check for acid before replacing just one.
One burnt compressor creating acid in the process destroys the other two. And the cycle never ends. Especially if you are not overdoing the clean up process.

Back top the thermistor. As mentioned of bad contactors. check the run voltage at the compressor. tighten all electrical connections. and be sure its bad and not something goofy.

[ChillerTech3384]

we have had similar problems in the past with failing/open sensors on the Danfoss compressors, specifically in the AuqaSnap chillers. I usually place a resistor across the sensor and educate the customer on the situation. I hate to sell someone a compressor if its not needed.

[Cool breeze 38]

I havent had to do this yet. I have not attempted to look it up. Whats the value of the resistor.

we have had similar problems in the past with failing/open sensors on the Danfoss compressors, specifically in the AuqaSnap chillers. I usually place a resistor across the sensor and educate the customer on the situation. I hate to sell someone a compressor if its not needed.