Hi - my house has two oil FHW zones. One covers most of the house and the other controls just a single radiator in the kitchen. This works out well for me becuase I heat most of the house with pellets, but that heat doesn't reach the kitchen very well.
Anyhow, the "radiator" in the kitchen is really an appliance which has a lot of coiled pipe and a couple of blowers to blow air across it. The motors have individual fan speed controls (manual). When it works, it puts out a lot of heat.
However, since I have lived here the last 2 years the fans will only run for a couple minutes at a time, and lately they hardly run at all. The kitchen is lucky if it gets to 60 degrees - and most of that comes from the pellets.
The circ pump for the zone works fine with its thermostat. You can hear it click on and off and the pipe gets wicked hot when it switches on, but the blowers don't go and without them hardly any heat comes off the exchangers.
The motors call for periodic cleaning and oiling, which I'm sure had never been done. I did that, but my problem is clearly an electrical issue as both motors will start and stop at the same time.
The unit's manual didn't say anything about a thermostat for the fans. But after watching the voltage on the motor terminals it was clear something was making it intermittent (and infrequent). I traced the cabling and found it going into a honeywell relay, which also pointed me to another thermostat cable coming out of that box. This relay and control cable are different than the one that drives the circ pump and is connected to the round thermostat in the kitchen. This second relay/thermostat is independent (parallel) to the circ pump thermostat. Tracing this thermostat cable found it snaked up behind the unit and I believe it is attached to some kind of surface mount sensor on the FHW pipe as the supply enters the unit. Is that a pipe thermostat? I can't get a good look at it, but I would say it isn't working well - that pipe is blazing hot but it only occasionaly allows power to the fans. It doesn't seem to have any way to set a threshold temp. The AC output from this second relay goes to the fan motors.
If I short the thermost cable together in a wire nut the fans run full time and there is good heat, until the circ pump thermostat cuts it off. But then the fans keep running.
My question: is there a reason that the fan and circ pump are on independent thermostats? Can anyone link to a potential replacement for that mis behaving sensor? My voltmeter tells me this is a 24volt AC system.
If there is no compelling reason, I am inclined to remove the second thermostat all together and attach the power for the fans to the output branch of the thermostat controlling the circ pump. That way the pump and fans for the kitchen run at the same time. Seems sensible, but I'm not an expert at this so I thought I'd ask in this forum if it made sense - and I'm left with the lingering sense that it was a lot of work and money to do it this way, so it was probably for a reason.
Anyhow, the "radiator" in the kitchen is really an appliance which has a lot of coiled pipe and a couple of blowers to blow air across it. The motors have individual fan speed controls (manual). When it works, it puts out a lot of heat.
However, since I have lived here the last 2 years the fans will only run for a couple minutes at a time, and lately they hardly run at all. The kitchen is lucky if it gets to 60 degrees - and most of that comes from the pellets.
The circ pump for the zone works fine with its thermostat. You can hear it click on and off and the pipe gets wicked hot when it switches on, but the blowers don't go and without them hardly any heat comes off the exchangers.
The motors call for periodic cleaning and oiling, which I'm sure had never been done. I did that, but my problem is clearly an electrical issue as both motors will start and stop at the same time.
The unit's manual didn't say anything about a thermostat for the fans. But after watching the voltage on the motor terminals it was clear something was making it intermittent (and infrequent). I traced the cabling and found it going into a honeywell relay, which also pointed me to another thermostat cable coming out of that box. This relay and control cable are different than the one that drives the circ pump and is connected to the round thermostat in the kitchen. This second relay/thermostat is independent (parallel) to the circ pump thermostat. Tracing this thermostat cable found it snaked up behind the unit and I believe it is attached to some kind of surface mount sensor on the FHW pipe as the supply enters the unit. Is that a pipe thermostat? I can't get a good look at it, but I would say it isn't working well - that pipe is blazing hot but it only occasionaly allows power to the fans. It doesn't seem to have any way to set a threshold temp. The AC output from this second relay goes to the fan motors.
If I short the thermost cable together in a wire nut the fans run full time and there is good heat, until the circ pump thermostat cuts it off. But then the fans keep running.
My question: is there a reason that the fan and circ pump are on independent thermostats? Can anyone link to a potential replacement for that mis behaving sensor? My voltmeter tells me this is a 24volt AC system.
If there is no compelling reason, I am inclined to remove the second thermostat all together and attach the power for the fans to the output branch of the thermostat controlling the circ pump. That way the pump and fans for the kitchen run at the same time. Seems sensible, but I'm not an expert at this so I thought I'd ask in this forum if it made sense - and I'm left with the lingering sense that it was a lot of work and money to do it this way, so it was probably for a reason.
