EcoRenovator - View Single Post - DIY thermal differential controller (solar hot water pump controller)

Xringer · 10-03-09, 07:50 PM

I had Solar Hot water for about 17 years, before the system started leaking a lot..
When we took it out, I kept the pumps (one is solid brass) and the controller.
I think it might have used 10k thermistors. It has pump control relays etc .
Anyways, if you are interested, I can dig up the controller and check it out.
Maybe we can do a deal.?.

Hey, just found it. It's a 1981 Novan C-30-1S, made by Independent Energy Inc.
The power LED still lights up, and I can hear the relay(s) working..

Got it open.. No insects!

Still looks okay inside. There is a temperature limit pot (blue).
The chip seems common.. RCA - CA324E

Just hook up the sensors, two motor leads into the sides and plug in the 120AC.

The relay contacts seem to be rated at 1/2 HP - 7.2 Amps at 120vac..

There is a slide switch on the side for OFF-AUTO-ON (on is for testing).
IIRC, I think you need two of the same type thermistors to make this work right.

This unit was mounted on the heat exchanger, next to the big tank
down in the basement. Never kept outdoors.

You never know, this thing might still work!!

10-03-09, 07:50 PM	#16
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I had Solar Hot water for about 17 years, before the system started leaking a lot.. When we took it out, I kept the pumps (one is solid brass) and the controller. I think it might have used 10k thermistors. It has pump control relays etc . Anyways, if you are interested, I can dig up the controller and check it out. Maybe we can do a deal.?. Hey, just found it. It's a 1981 Novan C-30-1S, made by Independent Energy Inc. The power LED still lights up, and I can hear the relay(s) working.. Got it open.. No insects! Still looks okay inside. There is a temperature limit pot (blue). The chip seems common.. RCA - CA324E Just hook up the sensors, two motor leads into the sides and plug in the 120AC. The relay contacts seem to be rated at 1/2 HP - 7.2 Amps at 120vac.. There is a slide switch on the side for OFF-AUTO-ON (on is for testing). IIRC, I think you need two of the same type thermistors to make this work right. This unit was mounted on the heat exchanger, next to the big tank down in the basement. Never kept outdoors. You never know, this thing might still work!!