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JBM HVAC, HVAC Technician
Category: HVAC
Satisfied Customers: 146
Experience:  Self Employed Air Conditioning, Heat Pump, and Gas Residential Installation/Service technician
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Oil furnace is blowing cold air. Filter looks partially used

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My oil heater is blowing cold air. The previous filter looks only partially used. I have turned off the power, replaced the filter. No change. Hit the reset button (not for the full 30 seconds as I now know I should) No change. Turned off power again and the reset button on a Honeywell R7 184a 1000 is flashing. The thermostat has read a consistent inside temperature of 53 for several hours, while a mercury thermometer reads 60. The thermostat is a White Rodgers.


I need to ask you a few questions first.

What is the make of the unit? also Model number

What type of unit is it? (forced air oil or oil boiler)

When the unit tries to start, what happens?

Customer: replied 8 years ago.

The oil burner is a Beckett model AFG Forced air oil. When the thermostat is turned up the heater fires right up

Can you see the flame or feel the flue (exhaust vent) heating up?

(if your going to feel the exhaust vent be very very carefull! when fully heated this pipe can be several hundred degrees)

Customer: replied 8 years ago.
The exhaust is cold

Ok, I have a hunch that most likely the fuel is not igniting or if it does ignite the cad cell is not sensing the flame.

I have one more question for you, does the Honeywell control go into lockout every time the unit shuts off?

If so here's what I would like you to do. Hold the reset button in for a full 60 seconds.

Then describe to me everything that happens while the burner starts up. This will help me get a better idea of what is going on in the system.

Customer: replied 8 years ago.
Held the reset in. The light went off. At around 30 seconds the light flashed twice. At 60 seconds relesed and something kicked on for around 20 seconds then shut off and the reset is now flashing green again

Ok that something that came on for about twenty seconds, did that sound like a sparking noise?

Also, after that did you hear, almost like a rushing type noise, of the fuel igniting after the spark?

Customer: replied 8 years ago.
Not a sparking noise-more like a rushing noise.

Ok, so then if you had to guess would you say the fuel is probably igniting?

If this is the case, your cadmium cell may have failed or may just be too dirty to sense the flame. The cad cell is in place, so that if no ignition is reached, the system does not continually try and restart. Because every time it tries to restart some fuel is injected into the chamber. If this happens over and over again, then you are at risk for an explosion. If I had to guess, from what you've described to me, I'd have to say that I suspect the cad cell.

Customer: replied 8 years ago.
Given the unused look of the filter I am sure something is too dirty to do the job. Last question: What does the flashing reset button mean?

I also have one more question to you, are you talking about the air filter or the fuel filter?

The flashing reset button means that the control (probably a Honeywell control) has locked out the burner. This is for the reason I mentioned before, continually trying to restart without ignition is extremely dangerous.

Customer: replied 8 years ago.
air filter

Ok, that's what I thought.

Definitely change the air filter if its dirty, this will improve the efficiency of the heating and air conditioning(if installed) systems.

I always recommend this to everyone who has trouble with an oil system: Get it serviced every single year. It is almost guaranteed that you will save money on oil and component failure.

I had a guy who was going through a tank a month, i serviced his boiler system, he has only used 1/2-3/4 of a tank so far this year in 3 months. If i could recommend anything to you it would be to get regular preventive maintenance done on your system.

I hope my answers were helpful to you!

If you need anything else, feel free to ask!

JBM HVAC and other HVAC Specialists are ready to help you