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Phil, Mechanical Engineer
Category: HVAC
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Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Janitorial Gas furnace blower will not shut off even when the

Customer Question

Janitorial Gas furnace blower will not shut off even when the thermostat is off. It is a 92% furnace.
Submitted: 7 years ago.
Category: HVAC
Expert:  gotoman for ac replied 7 years ago.
Does heat col work normally but fan continues to run. Russ
Customer: replied 7 years ago.
the blower starts by it self it started last night and the thermostat was off.
Expert:  gotoman for ac replied 7 years ago.
I need to know if heat and cool work ok before I can diagnose problem. On most furnaces if limit switch opens fan will run constantly. Russ
Customer: replied 7 years ago.
Ths e furnace was off for several days and about seven last night it came on and the thermostat was in the off position and the fan was on auto.
Expert:  gotoman for ac replied 7 years ago.
Last question if you turn thermostat to heat and turn up thermostat does furnace fire up. Russ
Customer: replied 7 years ago.

I will have to try it . The ac has not been on all winter the breaker if out of it. It was just a surprise as it came on by it self. I will get back to you tomorrow as the furnace is in another location.Don

Expert:  gotoman for ac replied 7 years ago.
OK I will be here. Russ
Customer: replied 7 years ago.

I will start the furnace and see if its works and check it all out Tomorrow. Do I get a hold of you through this company.

Thanks Don

Expert:  gotoman for ac replied 7 years ago.
Don we will leave question open so just reply back. Russ
Customer: replied 7 years ago.

I won't know til this afternoon about the furnace. Will check back as soon as I find out the information. Don

Customer: replied 7 years ago.

I checked the furnace and the air conditon neither of them ruDon but the blower still runs DON

 

Customer: replied 7 years ago.
We haven't heard from any experts why the furnace and air won't come on but the blower still runs. Waitingto hear from one of the experts. I will going there tomarrow and would like to know what to look for. Don
Expert:  gotoman for ac replied 7 years ago.
It is going to be board or limit switch. Janitrol will have diagnostic light inside blower compartment. Check the flashes and then check diagnostic. Chart. If light is off or steady on bad board. If you have an open limit flash. Check limit switches . It is located above burner with two wires coming out of it. Jumper switch and try furnace to see if it work. Do not leave it this way. Replace switch. Russ
Customer: replied 7 years ago.

Sorry I didn't get bqck with you sooner been very busy. I did go check the furnace on Saturday and when I arrived there he had everything shut off. We set the thermostat and turnded it on and the furnace was working perfect. So far no problems have happen since then. The fellow working with knew nothing about the furnaces and his son was there and he turned it on and it works. Thanks for your help even though we didn't use it this time. It may come in handy another time.

Don

Expert:  gotoman for ac replied 7 years ago.
Thanks or feedback. It is alaways nice to here there working OK. Russ

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