Furnace "lockout"?
Hello all. It is starting to get cold at night in Texas and my furnace is giving me grief. When I turn the thermostat up the blower turns on, the igniter sparks up it runs for 20 to 40 seconds and shu...
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Man does that sound familure..
It sparked
It lit
It shut down 3 times, then it locked out.
Now I did a major diagnosis job, I verified the thermocouple (which on my unit doubles as one of the spark contacts) was putting out the required 480mV (it was) I checked many other things and finally decided the control board was bad.
I contacted American RV in California (NOTE: Many States including Michigan and Georgia have companies called American RV, all different companies, you want the Californian one) (The other two I mentioned one put my new A/C on and the other does my oil changes).
I ordered a new DINOSAUR board, less than half the price of an OEM board.
Now I'm trained as an electronics technici9an, i've dabbled in electronics for ovewr 50 years.. When I opened the box my first impression was QUALITY, and upon closer inspection and comparision to the OEM board it was QUALItY!!!!!!!!!!!. Then I turned the board over and well. lets just say the font got bigger and more exclamation points. .. I have a theory as to what killed my OEM board.. Well seems the good folks at Dinosaur boards share it because right were it needs to be to prevent the failure I had is a handy dandy Gas Discharge type Spike supressor. I did have to make a minor change to how I mount it (used a Zip-Tie or two) but other than that.. Straight plug in replacement. and as of last week when I last used it.. Still working. (it was 2012 when I installed it)
If you want I can .. oh heck I will... Here is my trouble shooting boiler plate:
(This was created as I diagnosed my Furnace back in 2012.. Lots of time went into it, it's been vetted, I think I had to add one line after that as there was one thing I missed.. but if anyone knows anything I missed, PLEASE TELL ME, thank you.. nOTE most of it also applies to water heaters and all other DSI devices)
This document was created while I was diagnosing MY furnace.. I am told I missed one possible issue... Sadly I forget if I updated the document or not and the issue Bad connections anywhere along the line can lower voltage
When the T-Stat calls for heat the control board starts the blower (1)
The blower blows closing the sail switch (2)
The control board then opens the gas valve (3) and begins sparking (4.1)
Gas Flows (5) And ignitets (4.2)
The flame heats the flame sensor (5)
The flame sensor sends .480 volts to the control board (6)
which then detects the .480 and continues operation (*)
When the T-stat says "Enough already" (RV is now warm)
The control board shuts off the gas flow (*)
and then turns off the blower after a cool down (*)
*: At nearly every step the control board is involved. IF IT IS BAD, things will not work.. I recommend replacement boards from Dinosaur boards.. When Mine went out the Dino board was less than half the price and when opened the box the quality of construction and workmanship, and then design was very clear to my trained eyes.
1: No 12 volt to furnace, blower motor shot
2: Low 12 volt, air ducts clogged, blower "obstructed" bad sail switch
3: Bad solenoid, Clogged Gas Jet
4: .1: Bad ignition circuit (high voltage) on control board. .2: Points too wide (Very common it seems)
5: These do not often fail but they can
5: Bad connection, NOTE:
5 and * Bad wire.
* applies to all steps by the way So does bad wire/connection.
It sparked
It lit
It shut down 3 times, then it locked out.
Now I did a major diagnosis job, I verified the thermocouple (which on my unit doubles as one of the spark contacts) was putting out the required 480mV (it was) I checked many other things and finally decided the control board was bad.
I contacted American RV in California (NOTE: Many States including Michigan and Georgia have companies called American RV, all different companies, you want the Californian one) (The other two I mentioned one put my new A/C on and the other does my oil changes).
I ordered a new DINOSAUR board, less than half the price of an OEM board.
Now I'm trained as an electronics technici9an, i've dabbled in electronics for ovewr 50 years.. When I opened the box my first impression was QUALITY, and upon closer inspection and comparision to the OEM board it was QUALItY!!!!!!!!!!!. Then I turned the board over and well. lets just say the font got bigger and more exclamation points. .. I have a theory as to what killed my OEM board.. Well seems the good folks at Dinosaur boards share it because right were it needs to be to prevent the failure I had is a handy dandy Gas Discharge type Spike supressor. I did have to make a minor change to how I mount it (used a Zip-Tie or two) but other than that.. Straight plug in replacement. and as of last week when I last used it.. Still working. (it was 2012 when I installed it)
If you want I can .. oh heck I will... Here is my trouble shooting boiler plate:
(This was created as I diagnosed my Furnace back in 2012.. Lots of time went into it, it's been vetted, I think I had to add one line after that as there was one thing I missed.. but if anyone knows anything I missed, PLEASE TELL ME, thank you.. nOTE most of it also applies to water heaters and all other DSI devices)
This document was created while I was diagnosing MY furnace.. I am told I missed one possible issue... Sadly I forget if I updated the document or not and the issue Bad connections anywhere along the line can lower voltage
When the T-Stat calls for heat the control board starts the blower (1)
The blower blows closing the sail switch (2)
The control board then opens the gas valve (3) and begins sparking (4.1)
Gas Flows (5) And ignitets (4.2)
The flame heats the flame sensor (5)
The flame sensor sends .480 volts to the control board (6)
which then detects the .480 and continues operation (*)
When the T-stat says "Enough already" (RV is now warm)
The control board shuts off the gas flow (*)
and then turns off the blower after a cool down (*)
*: At nearly every step the control board is involved. IF IT IS BAD, things will not work.. I recommend replacement boards from Dinosaur boards.. When Mine went out the Dino board was less than half the price and when opened the box the quality of construction and workmanship, and then design was very clear to my trained eyes.
1: No 12 volt to furnace, blower motor shot
2: Low 12 volt, air ducts clogged, blower "obstructed" bad sail switch
3: Bad solenoid, Clogged Gas Jet
4: .1: Bad ignition circuit (high voltage) on control board. .2: Points too wide (Very common it seems)
5: These do not often fail but they can
5: Bad connection, NOTE:
5 and * Bad wire.
* applies to all steps by the way So does bad wire/connection.
