Davey Celsior Spa Bath Pump C400ABDESCRIPTION: Davey Celsior Spa Bath Pump. This pump has Heat Maintenance Technology this means it provides a stable maintained water temperature from the water cooled motor (It does not heat the water just maintains it) as per the other model, but it also has heat boost which means it contains a heater element also to heat the water. This model is 1500Watt with 2hp and a 1Kw heater element. It has the inbuilt air switch (air button sold separately)