• Please note, some of the links on our site are affiliate links (Learn More)

Furnace high limit switch and fan switch.

Joined
Mar 4, 2023
Messages
1
Location
s4p1v5
Model Number
MMHB-070ABHR-06
Age
6-10 years
I had some work done on my furnace, in a house that is new to me, and there was work done before, and now I seem to have an issue that I believe is new. When the furnace decides to kick in (temp on thermometer is not met) it will engage the burner and get hot, it heats for a few minutes, then, just as the high limit switch kicks out the burner, the fan engages, then it drops the heat in the furnace to a lesser level, then the burner engages again(with fan on) and this is when burner and fan operate at the same time, as normal. This whole process must be triggering the high temp switch on the furnace, but I don't know what is wrong.
I replaced:
Transformer
Fan motor
Nordyne 626337 Fan Control Switch F115-30
24V Fun Relay, 90-980 Isolation Relay AC Switch SPST

This is in a Nordyne (Intertherm?) mobile home furnace. As an aside, it does read 70 / 70 on the thermostat when the furnace kicks in. Is there any way to adjust the deadband?
Thank you in advance for your help.
 

Attachments

  • 20230303_153411.jpg
    20230303_153411.jpg
    360 KB · Views: 23
  • 20230304_112621.jpg
    20230304_112621.jpg
    220 KB · Views: 24
  • 1000001974.jpg
    1000001974.jpg
    339.3 KB · Views: 24
  • 20230303_153355.jpg
    20230303_153355.jpg
    382 KB · Views: 22
  • 20230303_153404.jpg
    20230303_153404.jpg
    364.5 KB · Views: 23
  • 20230303_153411.jpg
    20230303_153411.jpg
    360 KB · Views: 21
  • 20230303_160711.jpg
    20230303_160711.jpg
    397.8 KB · Views: 23
If you feel that you have benefited from this site, and would like to show your appreciation.
Top