Hello,

New to re site,

I was replacing a Carrier 06-E compressor and found that the crankcase heater, (plug into sump type) failed overnight. I checked it that afternoon all ok and found it not working and open cct the next morning. I had the system with oil to the base of the sightglass, and had left the system under vacuum overnight ready to charge the next day. It was a very old heater id say 15 years plus.

My boss has now advised me to leave crankcase heaters off while evacuating a system? Any truth to this? I would have thought its best to leave them on.

Cheers, James