Amana Heater Mod GUO090X50A
Posted 27 November 2006 - 05:16 AM
Shortly after I pulled the comforter off, the heater stopped heating though the blower keeps sending cool air through the ducts. When I checked it out, the bottom peep hole was blinking slowly but continously. I changed the filter, checked for any loose wires (none found) and put it back together--it blinked three times right at start up, then nothing.
Blower comes on, there's a click at the fuel valve but no flame.
Posted 28 November 2006 - 03:03 PM
The diagnostic chart says three blinks means the pressure switch is stuck open.
Posted 28 November 2006 - 06:05 PM
Posted 29 November 2006 - 09:07 AM
On power up with a call for heat, the exhaust motor should start first.
Check the pressure switch tubing for obstructions
Verify that the condensate lines are clear
Check the exhaust pipe for obstructions
If those check out ok then you will need to test the pressure(negative pressure) at the switch to move further.
If you are not sure what I am talking about let me know and I will try to explain it another way.
Posted 29 November 2006 - 10:27 AM
First, is the exhaust fan separate from the blower that pushes the air through the ducts or does the blower perform both functions, i.e. distribute heated air and exhaust air with condensation?
On power up, the main blower comes on immediately. So if there's a separate exhaust fan, I'll have to check this. I know what and where the exhaust pipe is---I'll check it.
Not sure where to find the condensate lines.
Is the pressure switch a gas pressure switch---the squarish metal piece near where the gas supply enters? If so, the tubing is the gas tubing?
Posted 29 November 2006 - 06:18 PM
Posted 30 November 2006 - 06:27 PM
The exhaust motor starts up immediately though rather than first, it's simultaneous with the main blower or a split second behind.
All the pressure switch tubing looks good, no kinks or obstructions.
I disconected the condensate lines as they leave the unit with no change at start up.
I checked the exaust pipe outside--it's coming out nice and steady and sounds just like it always does when I've ben near it in the past. Both the intake and exhaust pipes (2"pvc) run outside--both have a beefy screen to prevent tennis balls and whatever from being crammed inside.
I did also remove the air intake above the burner box--no change.
So I guess it's on to the pressure test?...
Posted 02 December 2006 - 05:54 AM
Posted 03 December 2006 - 07:49 AM
Posted 04 December 2006 - 05:49 PM
Only confusing thing is that soon after I hear the click I smell gas. Gas, click but no fire. Could we have a dead ignitor?
Back to the pressuer switch, I made the assumption that the voltage test was a test to be done indepenantly. That is, without reference to a manometer reading. If I'm wrong, let me know--I'll re-run referencing pressure readings.
Thanks--alot, the image came across with no fuzz--easy to interpret.
Posted 04 December 2006 - 06:43 PM
Am I reading correctly that the ignitor is glowing? Gas valve opens but does not ignite? Normal sequence is 1-combustion blower starts, 2-pressure switch closes, 3-ignitor warm up 17 seconds (50A55 Control),4- trial for ignition 3-5 seconds, 5-burner lights. Where are we in this sequence? Do you have a glowing ignitor when you hear the gas valve click?
It would be OK to remove the burner access cover to observe the burners during startup.
Ignitor resistance at 70-75F should be 50-400 ohms (usually around 100) - Amp draw is 4-5
Posted 04 December 2006 - 08:03 PM
Either way, I've looked each time and never seen any glow in the combustion chamber. I removed the cover plate at the burner box. There's a couple of red wires entering from above that connect to a white modue from which 4 one inch prongs descend into the combustion box. I went through start-up--no glow, no overall change at all.
The descending prongs looked rusty and frail so I poked gently with my screwdriver--the two middle portions fell off so I assume we have at least one part in need of replacement.
Posted 05 December 2006 - 12:22 PM
Posted 18 December 2006 - 07:52 AM
However, the red light still blinks three times on start-up. That's why we didn't go first to the ignitor---the control module says a three blink signal means the pressure switch is open.
Thanks for all the help.
Posted 18 December 2006 - 08:36 PM
The ignition control must pick up on the open pressure switch before the inducer motor has time to get up to speed. Usually the controls will allow some time before displaying a code.
Thanks for the update.
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