york furnace of woe
 

This is a York model G80C075120 Exterior forced air heater.
The blower, igniter and fan work, the main burners ignite but then shut off 5
seconds later; cycle three times and then shut down.
There is no error code.
Ive replaced the flame sensor
Purged the gas valve, measured 9v from the control board on the two leads
Re-inserted all the leads to the control board to insure good contact
and bypassed the thermostat by leaving the ground attached and connecting the
call for heat and blower wire twisted together with the same results. What
am I missing ?

york furnace of woe
 

i do not have your furnace. here are some thoughts:
gas boiler burner problems i've has: i had to replace the pilot
assembly and adjust the pilot flame to properly surround the flame
sensor.
different problem: replacing gas valve was required.
you must refer to your service manual on this problem and the service
pages of your furnace's components.

owmytoe wrote:
This is a York model G80C075120 Exterior forced air heater.
The blower, igniter and fan work, the main burners ignite but then shut off 5
seconds later; cycle three times and then shut down.
There is no error code.
I've replaced the flame sensor
Purged the gas valve, measured 9v from the control board on the two leads
Re-inserted all the leads to the control board to insure good contact
and bypassed the thermostat by leaving the ground attached and connecting the
call for heat and blower wire twisted together with the same results. What
am I missing ?

york furnace of woe
 

Reverse polarity will cause the problem you describe. Check and make
sure you have 120 volts from black to ground, and 0 from white to
ground. Larry

york furnace of woe
 

lp13-30 wrote:
Reverse polarity will cause the problem you describe. Check and make
sure you have 120 volts from black to ground, and 0 from white to
ground. Larry

Hmmm,
Ground is ground. 120V is between black(hot) and white(neutral).
Trying 3 times and quitting is sure sign of error condition.

york furnace of woe
 

buffalobill wrote:

i do not have your furnace. here are some thoughts:
gas boiler burner problems i've has: i had to replace the pilot
assembly and adjust the pilot flame to properly surround the flame
sensor.
different problem: replacing gas valve was required.
you must refer to your service manual on this problem and the service
pages of your furnace's components.

owmytoe wrote:

This is a York model G80C075120 Exterior forced air heater.
The blower, igniter and fan work, the main burners ignite but then shut off 5
seconds later; cycle three times and then shut down.
There is no error code.
I've replaced the flame sensor
Purged the gas valve, measured 9v from the control board on the two leads
Re-inserted all the leads to the control board to insure good contact
and bypassed the thermostat by leaving the ground attached and connecting the
call for heat and blower wire twisted together with the same results. What
am I missing ?


Hi,
It's funny he is talking about ignitor and flame sensor and you are
talking about pilot flame? Different subject.

york furnace of woe
 

If the polarity of the incoming power is reversed you will still have
120 volts between black and white and the furnace will do exactly as the
OP described. I have seen it happen before-- more than once. Make sure
the black is hot and the white is neutral. Around here, about 99+% of
furnaces are connected with a pigtail and receptacle, so the polarity
can be accidentally switched easily if anything is done anywhere in the
circuit. Most furnaces will run ok during a/c use that way-- it will not
show up until the heat is fired up. Larry

york furnace of woe
 

"lp13-30" wrote in message
...
If the polarity of the incoming power is reversed you will still have
120 volts between black and white and the furnace will do exactly as the
OP described. I have seen it happen before-- more than once. Make sure
the black is hot and the white is neutral. Around here, about 99+% of
furnaces are connected with a pigtail and receptacle, so the polarity
can be accidentally switched easily if anything is done anywhere in the
circuit. Most furnaces will run ok during a/c use that way-- it will not
show up until the heat is fired up. Larry

My furnace installation manual specifically warns about this possibility.
Larry's suggestion and method of testing are both valid.

Don Young

york furnace of woe
 

thanks for the tips...flame sensor double checked, reading microamps under
use...i'm afraid ground ( white ) is indeed ground

next step: a ball peen hammer

Don Young wrote:
If the polarity of the incoming power is reversed you will still have
120 volts between black and white and the furnace will do exactly as the
[quoted text clipped - 4 lines]
circuit. Most furnaces will run ok during a/c use that way-- it will not
show up until the heat is fired up. Larry

My furnace installation manual specifically warns about this possibility.
Larry's suggestion and method of testing are both valid.

Don Young

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