crankcase heater sizing

zepfan

does anyone know if there is a formula for sizing a crankcase heater for an air conditioning compressor (40 degree evaporator) As far as wattage per ton.I am trying to figure out if a 40 watt heater is too much for a ton and a half compressor for ac.thanks to all

pecmsg

I use the self regulating cable http://www.pentairthermal.com/products/heating-cables/crankcase-heaters/index.aspx

unclejohn

If it fits around the bottom it's the right one.