The control is a Varistat R.D. 601 temperature proportional setback control, the clock is analog. I talked to the manufacturer; they said this model is too old for them to support. The clock controls are not simple like those on an electric lighting timer. Also I would like your opinion on changing the other settings(ratio, etc.) from the defaults. The manufacturer did explain this to me, but I forgot the math. If you need it, I can send a digital image of the device.
Heat-Timer controls use the code OPN when they can not detect a sensor. For example, if someone were working in the building and cut the wires leading to the outdoor sensor, the HWR would begin to flash OPN to signal that the sensor was no longer attached. To find the source of the OPN reading,
I'm a homeowner in central NY State who is considering having an outdoor temperature setback control installed to reduce boiler water temperature during warm weather in order to save fuel oil. I have a oil fired 105MBTU hot water boiler with three baseboard heat zones and one indirect hot water heater zone. Boiler water is set at 180 degrees and the indirect hot water heater is set at 130 degrees. The three heating zone thermostats and hot water control are connected to four relays that turn the four circulators on and off as needed. There is no circulator that runs all the time. The boiler turns on and off as needed to maintain 180 degree water. This is not a condensing type boiler. The system works very well, but I believe I could save some money, by maintaining a lower boiler water temperature in the summer. I believe the boiler water temperature would have to be maintained at 140 degrees or above in order to heat the domestic hot water and avoid condensation of flue gas in the boiler and masonary (clay liner) chimney. what do you think? Is this worth exploring? Thanks for your help.
