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Hello, I have a Miller furnace and the blower stays on all of the time. I think it may be in one of the relays, I see it is a little melted. Also, is there a place I can view a wiring diagram for this unit? Thanks alot, Matt

Hi,

Go here to order a wiring/parts diagram:

http://www.mobilehomerepair.com/wireandparts.html


Is the blower running continously in heat mode ?



If so, do the elements and blower come on work fine, elements go off but blower doesn't ?


Can you feel ANY heat from registers and/or tell if at least one element is still on ?



Sounds like it may be stuck contacts in the sequencer.


IF you have a/c also, does the blower stay on continously in Cool mode also ?




Thanks,
Robert

Hello Robert, thanks for the reply. The heat & AC click on and off just like they should, but the blower will remain on, not blowing cold or hot air, just ventilation like the fan switch on the t-stat is turned to 'on' instead of auto. Thanks for the diagram, the relay that has a burnt area on it is the 621898 relay and it is burnt around the NC connector. Don't know if this is what it is or not. Thanks alot. Matt

Hi,

The Blower Relay 621898 and 621899 both control blower motor in cooling and continous fan modes.


The sequencer controls the motor during heat mode.


Since it does it in both, most likely one of the blower relays.


The 621898 showing burnt spots would be likely suspect.


The 621898 is a N.O. relay and the 621899 is a N.C. relay.



Most likely a set of contacts fused shut and the continous running heated up relay causing burnt markings.



The Blower Relay 621898 is available for ordering in our Nordyne Electric Furnace parts page.


Go to HVAC link in toolbar, then to Furnace Parts and then the Nordyne Electric page.



Thanks,
Robert

Thanks alot Robert, I ordered both of the relays just in case. And I found a wiring diagram and it looks like the previous owner just wired it straight through from the breaker to the blower when he saw the the relay was cooked. Hopefully after getting the new relays and wiring it correctly the blower will come on and off like it's supposed to. Thanks again, Matt

Hi Matt,


You're very welcome and thank you for ordering with us. Hopefully that will take care of it.

Either way, please update us with results.


Thanks again,
Robert

Hello Robert, I received the relays today and got them installed, and it seems to have corrected the problem. The blower is now kicking on and off like it should. What do you think could've caused the relay to burn up like that right at the NC connector, it was burnt and melted very bad only in the NC area of the relay? Well, thanks so much for your advise, it saved me a ton of money! Thanks, Matt

When relays stick and components run non-stop, they build up heat and it is passed on to the relays.


A loose wire can do same cause and arc that burns plastic relay.



Glad it is fixed and you're very welcome.


Thanks,
Robert