Lennox Question

[toddsranger]

I am working on a Lennox straight air-conditioner. It has one of those band type crankcase heaters. Why does an air-conditioner have a crankcase heater? I don't see how refrigerant could migrate outside, since it doesn't run in the winter. Is a crankcase heater something that come on these units, or did someone add this? I am a technical student and was just wondering! Thanks!

[toddsranger]

Could the band be used in a commercial application (like a restuarant) in low ambient conditions, where they would still need to run the air conditioner? Just a thought!

[RoBoTeq]

It makes getting the oil through the system a bit better when the oil is more viscuous (thinner) and the crankcase heater keeps the oil warm and thin. Most older units had band type or immersion type of crankcase heaters to this job.

Since a crankcase heater requires energy that takes away from efficiency rating, more and more manufacturers are removing the crankcase heaters and using a shunted contactor to allow a trickle charge of current to run through the compressor windings to keep the oil from loosing its viscosity. This saves about a half a SEER in energy rating.