G73 / FUH54 thermostat failure

[rieferman]

On another forum, a G73 owner had the thermostat overheat. He was concerned about fire hazard, and whether this could be a possible recall situation etc. I contacted Marley (they brand the FUH54, same unit as the G73) and the engineering manager sent me a thorough reply. I have spliced his emails into one quote below, but other than combining two messages into one, have not in any way changed his message.

Summary (according to Marley engineer): Not a fire hazard. Isolated issue that is more likely to occur with units purchased more than a year ago. To proactively check, periodically inspect the wiring to the thermostat (cut power to unit first) for any signs of discoloring.

I hope this is helpful to the group.

Happy Holidays,

Your email was forwarded to me. To address your questions and
comments, we have seen a few heaters over the years that have had issues with the
thermostat wire connections, but not a large number by any means. A
few years ago we experienced a higher number of failures where the crimp
connection of the wire to the thermostat was incorrect allowing the
connection to heat and fail. Since resolving this with the supplier
at that time, I am not aware of but a hand full of failures.

The thermostat and wire connections are all located within an all
steel wiring compartment. Our experience is that the failure of this
connection has resulted in no hazard due to it being totally contained with this
grounded steel compartment. It is unfortunate that any failure would
occur and we have taken appropriate corrective action with our suppliers to
help make sure this problem is corrected. However, if a thermostat happens
to fail within the warranty period, we will gladly replace the
thermostat at no charge. If it happens to fail after the warranty has expired, we
generally will provided a free replacement thermostat anyway as a
customer accommodation.

Since we see so few failures and they are random, I can't provide any
specific model or date code. The only thing I might suggest would be to
periodically shut power to the heater, open the wiring compartment door and
inspect the wire to see if it has begun to discolor. This would be a early
sign of the connection heating and should give you a chance to obtain a new
thermostat before the heater quit working.

I understand that you are concerned with the safety of this heater
and that this failure might pose a hazard. However, our experience is that it
is an unfortunate event, but that it should pose no hazard or risk for
fire. If you have a problem with your heater, please contact our toll-free
technical service hot line for assistance at 1-800-642-HEAT (4328).

 

[Interex]

Good info. I checked all of my connections before starting up my unit. Might be a good idea to take another look at them.

 

[OVRPWRD]

Mine did the same thing. Thermostat burned out causing it to run constantly. Just got it last December. Not even a year old with probably 15hrs of run time on it.
Yes, i use the search funcrion and am bringing this back!!

 

[dk3]

Stumbled on this. Looks like there is a revised FUH54c that uses a relay instead of a line-voltage thermostat. The old design seems like a fire hazard.

 

[larry4406]

Stumbled on this. Looks like there is a revised FUH54c that uses a relay instead of a line-voltage thermostat. The old design seems like a fire hazard.

Any details on this? My google search came up empty.