I keep blowing the high limit fuse. What I have done; cleaned dryer and vent lines, replace heating element and replaced motor about three months ago. The dryer with new thermal fuse kit will heat for a short period and then blow the fuse what could be the problem? I have ordered a new relay and thermistor but at a loss as to what is going on.
Any ideas, would reall be appreciated.
Would a bad relay keep blowing the high limit fuse?
Which fuse is blowing?
There are two hi-limit fuses in the unit.
One on the blower (thermal fuse) and one on the heater assembly (thermal cut-off).
The one on the heater assembly. The one nearest the back of the dryer.
I do not believe this! I have now replaced the relay, and another thermostat kit and it blew the high limit fuse on the heater box again!! As mentioned before I cleaned the blower, the exhaust line and there is no obstruction to the air circulation. What could be causing this? Help!! as I am ready to just jump the high limit cut out!
See the attachment for your tech sheet
I am assuming that the hi-limit kit you installed included the thermal cut-off and the high limit thermostats.
Unplug the unit and both wires at the heater.
Measure across the heater, should be about 8 to 12 ohms.
Then measure from each heater connector to the frame, both should be infinite ohms.
Be sure to find a spot with bare metal and/or Neutral if it is a 3 wire hook up
The hi-limit thermostat should regulate the temperature so that the thermal cut-off does not blow but this will not work if an element is grounded.
Also you had said that you ordered a thermistor, did you also replace it?
Check all internal seals in the unit.
The hot air is pulled thru the heater then the drum (this is all therefor under a slight vacuum) and then pushed out of the unit.
A seal/air leak can pull in room air which the thermistor sees as cooler so it keeps the heater on.
You could also check the exhaust temperature, see page 5 of the tech sheet.
68932790.pdf (164.6 KB)
I do not know if this will help with the diagnostics, but as I do not have another thermal cut out kit, I jumped the high limit and ran the machine on permanent press and the heater element cycled from on and off. I do not like this but until another, 4th kit, arrives not many other options.
The thermistor has not arrived and maybe that is the problem. As before I have replaced the relay and the burner. Is it possible that the problem is in the board assuming there are no air leaks? If it is in the board I am off to Lowes for new machines.
You cannot assume that the heater is OK, you have to check it. Then at least you can eliminate it as the cause.
PS- it is the most common cause of the thermal cut out blowing.
Also have you checked the air flow out of the unit?
The most common cause of the cut-off blowing is a grounded heater.
The temperature then cannot be regulated by the board so the unit runs off of the high limit thermostat. A symptom of this is that it will run hot on any temperature setting (low etc.). The contacts in the high limit eventually weld together and then the cut-off blows.
Still waiting on new thermistor and thermal fuse kit, but today I inspected the heater and did as you instructed and did not find any continuity between the heater elements and the dryer. Would a bad thermistor cause my thermal cut out to blow? I am still using the dryer, reluctantly, with the cut out jumped.
Thank you for all the information and time you have given me.
You are welcome.
I just wish we could find the cause.
Yes a bad thermistor could be the cause.
When you replace it check that the heat varies with the settings, see the tech sheet. I would start with the lowest temperature.
Other than the thermistor the only other thing I can think of is the control board.
Finally replaced the thermistor and that seems to have been the problem! Well I have a like new dryer now. Thanks again for your assistance, whish I could buy you a beer or two!