Conifer Solar Consulting supports the solar industry by designing and repairing active solar heating system controls and providing controls-associated consulting. Brands of controllers that I repair include Heliotrope, Independent Energy, Novan, Honeywell, Solar Controls Corp., Rho Sigma, Taco, Solaron, Johnson-Penn, Apollo (NDI), Webb, SDI, Dynatech, Richdel, Dencor, Western Solar Products, and upon occasion, other brands. Brands I don't repair are Robertshaw, HI Square/Hawthorne, Dan-Mar, and those controllers that use thermocouples for the temperature sensors. Typical turn around time is two days.

I have acquired the controller inventory from a Denver Solar Service company and a local Denver metro area community college that has shut down its solar technology program. I've gone through these controllers and have repaired and checked them out and they are now ready to sell. They include:

Heliotrope DTT-71
DTT-74 older model (uses 3 K ohm  sensors)
DTT-74 newer model (uses 10 K ohm  sensors)
DTT-74/Eagle DTC-30 (uses 3 K ohm sensors)
DTT-74-ST/Novan Sunsensor (uses 10 K ohm sensors)
DTT-80
DTT-80 (40/20 differential)
DTT-80-ST
DTT-80 (12 VAC input)(new)
DTT-81
DTT-82
DTT-84-ST (old model uses 3 K ohm sensor, no cover)
DTT-84/Grumman (uses 10 K ohm sensors w/remote LED)
DTT-90
DTT-400 (1 w/o cover)
DTT-403 (1 w/o cover)
DTT-3410
DTT-3411
DTT-5082/Grumman (uses 10 K ohm sensors, this controller can directly replace the IE C-30/Grumman and RS-121/Grumman controllers)
SP-Lo set point controller
The above controllers are priced at $36.50 each.

Heliotrope models DTT-690, Eagle DTT-690, DTT-691, DTT-790, and DTT-5080 (drain down), are $42 each.

The remaining Heliotrope models are:
DTT-80R (new) $52
DTT-80T-ST Temp-Trak $62.50
DTT-90T Temp-Trak $62.50
DTT-92T $62.50
DTT-792T $72.50

Independent Energy - GoldLine:  
C-35-1S-2S(DHW)-3T $83
C-60 $32
C-120 $155
DM-30 monitor $72.50
GC-1 snap switches (new) $11
ABC 10C/14 Buss Cable Adapter kit $11

Webb Systemizer III (Continental Solar), $129 for display box, $52 for power/relay box
Novan DLP-20 (display only) and 2011 (10 K ohm sensor) digital display controllers $104
Rho Sigma RS-121 w/o cover $36.50
Rho Sigma RS-121/Grumman $36.50
HI Square DC120 controllers $36.50
Hawthorne control test set/H-1600 $52
Webb 990 controllers $26
NDI/Apollo 44 $26
Johnson/Penn R34DCH-1 $42
Solaron HC 0215 control unit (new) $155
Solaron HC1011 with accessories (new) $258
Honeywell C773A sensors (new) $16
Solar Controls Corp. 80-171RA $32
Solar Age Partner/Hi Square 4020 $32
Cyclops SW-120 controller with ST-310 control tester $52

10 K ohm sensors (new), 3/8" dia., 2 1/8" long with 50" leads $12.50 ea.

Prices shown do not include postage.

Yes, I accept payments through PayPal.