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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a modine pd200 can't read the rest of the numbers.

Customer Question

I have a modine pd200 can't read the rest of the numbers. But the blower fan comes on when it is supposed to but sometimes the fan stays on for a long time after the burner shuts off and it blows out the pilot light. It is a commercial greenhouse heater.
I replaced the fan delay timer but it did not help
Submitted: 1 year ago.
Category: HVAC
Expert:  gotoman for ac replied 1 year ago.

If pilot light is going out I would replace thermocouple first. Second after I replace thermocouple and pilot is still going out. I would check for leaks in heat exchanger. If fan is blowing out pilot as you say you have a hole in heat exchanger. This allows carbon monoxide to get into area. Dangerous situation for workers or anyone in the greenhouse. Replace thermocouple and retry furnace. You can also buy a carbon monoxide alarm at any big box store. Russ

Customer: replied 1 year ago.
The first thing I did was replace the thermocouple. Let me explain the situation again.
Sometime the blower fan does not turn off after the burner shuts off. It may stay on for hours. When this happens it blows out the pilot light.. So the problem is with the blower fan. It is supposed to shut off after the burner has shut off.. I have replaced the thermocouple and the fan delay.. The pilot does NOT just go out... the fan does not shut off when it is supposed to... So is there some other device that hooks between the fan and the delay. I can't find any schematics for the furnace..
Expert:  gotoman for ac replied 1 year ago.

The only other part that would cause fan to not shut off is the limit switch. If it is bad it will cause fan to run till it resets. It is a safety device in case fan relay does not work. Russ

Customer: replied 1 year ago.
Okay so where exactly is this switch located? The diagram looks like a squid floating in mid air
Expert:  gotoman for ac replied 1 year ago.

Should be straight above burner. In middle. That unit is hard to find diagram. Russ

Customer: replied 1 year ago.
I have to drop the burner?
Expert:  gotoman for ac replied 1 year ago.

NO it will be accessible . Just above burner has two wires attached. May be closer to stack. Russ

Customer: replied 12 months ago.
I don't know if that has helped yet. I am still waiting for the part to get here and then I have to wait for it to get cold enough for the heater to come on
Expert:  gotoman for ac replied 12 months ago.

How are you doing with heater part. Russ

Customer: replied 12 months ago.
Well I have it in now. I just have to wait until the temp drops to 36 degrees for the heater to come on.. Not gonna burn several bucks worth of propane for no reason
Expert:  gotoman for ac replied 12 months ago.

Understand. Russ

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