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Joe
@sbcglobal.net

Joe to SandShark5

Anon

to SandShark5

Re: Furnace does not turn on

No, I have paid an outside company to fix it. So far they have replaced the thermostat and reset the flame sensor twice. I will try to narrow the trouble code down, so far none of the repairmen said anything about the ignition, but I really don't think they looked hard enough. I thank everyone for their help, it will help me when talking to a repairman, I don't know enough to try it myself.

SandShark5
Long may you run
Premium Member
join:2000-05-23
Santa Fe, TX

SandShark5

Premium Member

I don't get it. You've paid $800 to have your furnace repaired and still it's not repaired? I think you're being taken for a ride.

Joe
@sbcglobal.net

Joe

Anon

Yes, I think I am. I called a new technician after the last one put duct tape over a switch. It is very hard to find a good person to help, that is why I came here, so I can het help when talking to them. Will let you know how it goes, thanks.

leibold
MVM
join:2002-07-09
Sunnyvale, CA
Netgear CG3000DCR
ZyXEL P-663HN-51

leibold to Joe

MVM

to Joe
The first thing to narrow down the cause of your problem is to distinguish between your furnace failing to ignite a flame (when the thermostat first calls for heat) and your furnace failing to detect a burning flame in the middle of a heating cycle (furnace goes off while thermostat is still calling for heat).

The manual posted by SandShark5 See Profile states that the original trouble code (11 or 13) is stored in a buffer when the furnace goes into the one-hour-retry mode. What I didn't see in the manual (but I didn't read it front to back) is how the buffered fault code can be retrieved. It could be as simple as showing after the expiration of the one hour retry delay or it could require special diagnostic tools.

Failing that, you may be able to distinguish between the two types of failures with your own observations of furnace status and thermostat. Many digital thermostats will show whether or not they are currently calling for heat/cold. Whenever you notice your furnace to go off, immediately go to the thermostat to check if it is still calling for heat. If the furnace ever turns off while the thermostat is still calling for heat then the code 13 scenarios apply.

The other thing you may be able to do is to frequently check the status display on the furnace. It will show failure codes 11 or 13 between the 1st and the 4th failure (after the 4th failure the display changes to "r").

Knowing whether you are dealing with repeated code 11 or code 13 failures eliminates half the possible causes. The flame sensor is the only part that could be responsible for both codes.

Taken
@videotron.ca

Taken to Joe

Anon

to Joe
800$ for a 12 year old furnace... Almost half the price of a new one (+/- 700$).

I never would have agreed to that price fro a 12 yr old furnace.

Coma
Thanks Steve
Premium Member
join:2001-12-30
NirvanaLand

Coma

Premium Member

said by Taken :

800$ for a 12 year old furnace... Almost half the price of a new one (+/- 700$).

I never would have agreed to that price fro a 12 yr old furnace.


On a side note, last week, I replaced a 37 year old oil fired hot air/AC system with a high efficiency furnace, heat pump and new oil tank for $8500.

Joe
@firstcomm.com

Joe to leibold

Anon

to leibold
I think I have found the codes. When the r was flashing, the thermostat says "System On" calling for heat, but the furnace is idle. When I shut the power off to the furnace, wait a minute, then turn it back on, I get a 1, then a 1 real fast, then a pause, then a 1 and a 1, then a pause and it repeats, which I think is 11. The furnace starts, I see the flames and then displays an H. Do you think it is the flame sensor or something with the ignition? I do see flames come on, but sometimes they do not stay on and it will display the r again. Thanks for all your help.

leibold
MVM
join:2002-07-09
Sunnyvale, CA
Netgear CG3000DCR
ZyXEL P-663HN-51

leibold

MVM

said by Joe :

I do see flames come on, but sometimes they do not stay on and it will display the r again.

That observation helps to narrow down the possible causes. The error code 11 means failing to ignite, but since you can actually see the flame the most likely problem is the flame sensor.

Per troubleshooting section 11.F:
- check wiring and connections of the flame sensor
- check whether flame sensor is properly mounted in the path of the flames and grounded
- check polarity of the voltage and measure the current through the flame sensor
- clean the flame sensor rod

Not mentioned in that section, but if all else fails replace the flame sensor with a new one.

SandShark5
Long may you run
Premium Member
join:2000-05-23
Santa Fe, TX

SandShark5 to Joe

Premium Member

to Joe
Function Code 11 - Failed Ignition Trial

Description - No flame sense during ignition trial. Remains displayed until successful ignition, one hour retry is started or heat demand is removed. Fault is stored in buffer after four consecutive failed ignition trials in a single heat call.

A. Insufficient line gas pressure
1. Insure gas supply is connected to furnace and check for proper line pressure.

B. Gas valve control turned “OFF”
1. Turn gas valve to the “ON” position.

C. Insufficient manifold pressure, gas valve “ON”
1. Check 24 VAC to gas valve.
2. Check for 170 - 190 mAmps to servo valve.
3. Adjust valve for proper manifold pressure at 100% rate.
4. If gas valve will not adjust, replace gas valve.

D. No spark at electrodes
1. Check 120 VAC at igniter control during ignition trial.
2. Check spark wire connection at igniter control transformer and electrode.
3. Check for short to ground of electrode (cracked ceramic, touching burners, etc.)
4. Check igniter wire for damage.
5. If all checks OK, replace igniter control.

E. Burners don’t light
1. Check for proper mounting and placement spark electrode assembly.
2. Check for proper mounting of burner assembly.

F. Burners light, but extinguish after 8 seconds or less
1. Check for proper polarity of line voltage.
2. Check flame sensor wiring and connections.
3. Check for improperly mounted flame sensor (positioned out of flame, grounded).
4. Check flame sense current.
5. Clean flame sensor rod.

Joe
@firstcomm.com

Joe to leibold

Anon

to leibold
Found the problem, took out the burners, they were very dirty and needed cleaning. Occassionaly the last one would not light because of the dirt preventing the gas from going down the channel, thus tripping the flame sensor because no flame was on it. Thanks for all your help!!!

leibold
MVM
join:2002-07-09
Sunnyvale, CA
Netgear CG3000DCR
ZyXEL P-663HN-51

leibold

MVM

I'm glad you managed to find and fix the problem. Furnaces aren't really my area of expertise it didn't occur to me that an uneven burn might leave the flame sensor unexposed.

Good job!

That must have been exceptionally bad service from the company that charged you $800 and didn't notice the dirty condition of the burners.

jack b
Gone Fishing
MVM
join:2000-09-08
Cape Cod

jack b

MVM

I'd think about asking for a refund...