Tuesday, May 22, 2007

To PV Pump or Not to PV Pump (Conventional Controller and Pump)

Solar DC pump (also called PV pump) is a mixed bag.

The good:

You never pay to run the pump (free electric)—might be a buck or two a month.
The “control system” is elegantly simple…when the sun shines, is when the water is getting hot, and then the pump run automatically to bring the hot water down.

The Bad

If you go on vacation, its harder to control the maximum temperature or prevent overheating. We do add a switch so you can turn off the pump, though.
It costs $250.00 more than standard system.
The DC pump motors tend to have a little highly service rate than AC pump motors.
If inside a living space (laundry room or bi-fold door closet) they do make some noise that changes as clouds go by.

The Neutral
If you have the 120V plug in controller, even in power outage, you can just plug this into your computer UPS and you will be producing hot water.


  1. Regarding using an UPS from your PC to make hot water. Although the UPS can power the Steca controller, you're still going to need power for the 220V pump and if you don't have your 120v power, you probably don't have the 220v either.

  2. Anonymous---When using the 120V STECA plug in controller, the circulation pump is 120V and also plugs into the STECA controller. So both can be powered by the UPS.

    But you are correct, if you have a 240V pump, the UPS idea will not work.