Flame Sensor on Amana GSI090D50A

Hello,
My Amana furnace(22+ years old) does not come on. There is a problem with the flame sensor. It is intermittent. My HVAC service tech came out last week and repaired/cleaned the flame sensor. Cleaning the sensor did not solve the problem completely.

Apparently, the Blue-36 wire that runs from the flame sensor to the adaptor at the firewall is not making good contact(maybe from vibration) in the mail adaptor. I turned the power off at the unit and then pushed on the wire at it's connection at the adaptor. I then turned the power back on and the flame sensor worked. However, it stopped again later today. So, I am not sure how to make this repair.

Will a new flame sensor install into this adaptor? Not sure if the new Blue-36 wire merely "clicks" into the adaptor in order to make contact. The part seems simple enough to replace.

Any help would be appreciated. I already have a >$230 estimate for replacing the flame sensor. Ouch!

 

Welcome to the forums.

At this point it's probably not the flame sensor rod itself. The flame sensor is only half the circuit. The other half is the return ground path back to the control board.

You need to check/tighten the screws on the burners as well as the control module.

 

Did your tech measure the flame rectification?




Unless the porcelain is cracked you probably don't need to replace the flame sensor.



If the wire connector to the flame sensor is loose you may be able to tighten the connector with some needle nose pliers.



The flame sensor is only part of the flame rectification circuit.
I would also clean the ground connections to the furnace.
If the ground wire connects to a junction box in the furnace the connection from this box to the body of the furnace should also be cleaned.



The face of the heat exchanger that is exposed to the flame and the face of the inshot burners that is exposed to the flame may also require cleaning.

 

Probably too busy writing up the bill.

 

Thanks PJmax for the welcome! I agree that the flame sensor rod is not the problem. I will do the check/tighten of screws as noted.

I am not sure if the tech measured the flame rectification. That's a term I was not familiar with until this morning. However, I suspect that he did a thorough diagnosis. Flame rectification is probably not something that they would normally try to explain to a homeowner.

Am I allowed to post pics?

Appreciate the help!

 

Hi Houston204,

Thanks for weighing in. Like I replied to PJmax I am not sure if the tech measured the flame rectification, although knowing the thoroughness of this particular company I suspect he did.

My flame sensor is the one you have pictured on the left of those excellent pics.

The first trip out last weekend, the tech did clean the rod on the flame sensor and made some repairs between the flame sensor and connection to the controller.

I will check the ground connections as well.

If I am allowed to posts a few pics I would like to do so.

I will post up what I find when I go back up into my attic later this morning.

Appreciate the help!

 

The DIY board encourages you to post pictures. In my link you'll find some easy to follow instructions. If you take large pics..... which are the most helpful.... you'll need to host them on a site like photobucket and link here. http://www.doityourself.com/forum/el...-pictures.html

 

I will work on posting some pics after lunch. I had a long post and clicked on the post quick reply and wouldn't you know it, I was not logged in and the whole enchilada was lost!!!

To make a long story short, the furnace has been working for the past hour and half after I did this:

I put pressure on the bottom half of the blower deck connector(from the burner side) while the burners were attempting to light. Holding pressure(with an insulated screwdriver) the burners lit, the air circulation blower engaged and heat was then distributed thru the duct work.

This is where the problem lies IMHO.

Pics to follow.

 

Here goes with some pics: 9 + one video

The first is the nameplate of the furnace

Recent repair by HVAC tech

Flame Sensor

Blower Deck Connector(as seen from the burner side)

Control Module + Female Connector

Blower Deck Connector(Female)

Blower Deck Connector(as seen from the burner side) - the flame sensor wire(BU-36) is slotted in the lower right corner or #3 in schematic.

Door Connectors(seem to missing a couple of these)

Control Module + Blower Deck Connector - better lighting

Here one video: This was just before I put pressure on the lower side of the Blower Deck Connector(with my insulated screwdriver), after which the unit operated normally(and it currently operating normally). Tomorrow morning is another story.


Thanks for any help. It's appreciated.

 

This connection screams intermittent to me. These plugs get corroded all by themselves and yours looks like it got wet.

 

So far, my furnace is operating normally. I have not checked on Amana wholesalers for parts etc.
I would like to know if there is a way to repair the connection. I don't want to replace the furnace unless I am forced to. Do the individual wires push-pull in those connectors?

 

>



I agree with PJ Max.



I remember a commercial boiler I was working on once. It had a Honeywell ignition control that wasn't working reliably.

I sweated bullets over it for a couple of hours, and was ready to give up on identifying the problem, when I wound up leaning against it. Bingo!


The copper tabs had some corrosion and weren't making good connections.

 

Still having the intermittent problem causing the furnace to not cycle properly.

Most recently, I disconnected the blow deck connector and disengaged the female plug from the firewall. I used emery cloth to clean the inside of the female connection and outside of the corresponding male connection. Reinstalled the plug and the furnace immediately worked as it should. I thought I had solved the problem(corrosion as noted in earlier posts to the thread).

The furnace ran normally all that day. I turned up the heat right before going to bed and still working normally. The next morning, NOTHING! Very frustrating.

I am reluctant to keep disconnecting the blow deck connector plug, since it was not designed to be disconnected frequently.

I see three possible solutions: I am not ready to replace the furnace.

1. Disconnect the blow deck connector and re-clean the contacts.
2. Use a contact spray to improve the connection.
3. Do a work around. Remove the BU-36 wire from the male side(burner) and
feed through the firewall into the control side and reconnect using nylon
insulated disconnect(either 22-16 or 16-14). A wrap with electrical tape
would complete the connection.

To this non-professional, #3 seems like a permanent fix.

I also checked on availability of the wire harness and of course it is not available.