Dayton 3UH62 furnace house blower not working.

Eric1973

Blower motor was going out on our furnace, ordered a matching Protech motor as a replacement along with a new run capacitor. Finished it up last night and went to test it. Exhaust blower kicks on then the burners light. The house blower never kicks on, which I assume triggers a high temp limit shutting the burners off. The green OK light on the board is flashing in a three blink pattern, I am assuming this is a fault code for a temp limit but cannot find the definitions for the codes. Any ideas on A reason the new motor is not turning on?

Thanks Eric.

JUGHNE

If you have a T-stat with a "fan" switch, does the fan run when you go from auto to "on"?

Eric1973

Ok, sorry for the delay I just got home. Turned the fan on at the stat and it runs. Not sure it’s at the full 1075rpm, but it is running and sounds ok.

JUGHNE

What were the symptoms of the first motor failing?

Eric1973

Slow to start, then once it was up to speed it would run for a while then start squealing and slowly come to a stop.

JUGHNE

With the fan running with the on switch, you could fire the furnace and see if the heating works. Fan may be running on high speed, but you can do this for testing or just to warm up.
The board has a timer to start fan after a call for heat.

But first:
Are you sure of the motor connections on the board?
Probably a white common which must be OK if motor runs now.
3 or 4 speeds......you would use 2 (heat & cool)....
the other 1 or 2 would park on unused leads/speeds.
(The cap leads are probably brown and obvious connections)

If that is all right then you may have a bad fan control board.

Eric1973

First pic is before fan motor removal, second is after new motor was installed. All wires went back to the same spot according to color.

Eric1973

Trying to figure out how to have the fan running and then fire the furnace with a nest thermostat. It’s not going so well. Lol

JUGHNE

Won't the Nest let you turn the fan "on" when you have a call for heat?

Eric1973

So far I can have the fan on, then call for heat and it shuts the house fan down and starts the exhaust fan then fires the burners. Still looking for a way to do it with the house fan running.

JUGHNE

Could you post more pictures:
Remove all the fan motor wires from the board so all the writing may be seen. Picture of that please, I am not familiar with that board so I need help.

Also a picture of the wiring diagram that shows the board connections.
Thanks

Eric1973

It looks like the part number comes back as a Rheem board. P/N 62-24136-01. I’ll get some pics in a bit.

HVACNUT

The terminals on the board should be labeled Heat, Cool, Cont (for continuous fan) and Park or Unused.
We can't see the designation on the board.
If a motor lead is connected to the heat terminal on the board and the fan doesn't run, it's probably a bad relay in the board, OR, is there another control mounted below the board with some wires and a dial?

Jamie Hall

Some fan controls have a timer, but it seems to me that I recall from somewhere (how's that for vague -- hot air isn't my thing) that sometimes there is a thermal switch which delays the fan start until the furnace is up to a minimum temperature?

Eric1973

After playing around with it last night and this morning, I have come to the conclusion that it has to be a bad fan timer relay. Everything works separately. Then when you bring the timer into the picture it will not run. Now to see if I can find a board locally, if not I’ll order one and hopefully have it by Tuesday. I’ll update after I change the board to see if it fixes the problem.

HVACNUT

Is the time delay relay in the board, or mounted below the board?
Most older Rheem furnaces have a seperate TDR for heat.

JUGHNE

It is frustrating for repair people to find one problem and suddenly there are two bad parts.
The best explanation I could offer is that the old motor was overheating the heat relay as the motor stalled and drew locked rotor current until the motor overload opened.
This heat damage may be visible on the back side of the board where the relay is soldered onto the PCB.

Nest question for Wallies: can you run the fan constantly in the heat mode if using a Nest Tstat and conventional furnace??

Eric1973

> @HVACNUT said:
> Is the time delay relay in the board, or mounted below the board?
> Most older Rheem furnaces have a seperate TDR for heat.
>
Here is a picture of everything.
Not sure why my picture ended up in the next comment down?

Eric1973

> @JUGHNE said:
> It is frustrating for repair people to find one problem and suddenly there are two bad parts.
> The best explanation I could offer is that the old motor was overheating the heat relay as the motor stalled and drew locked rotor current until the motor overload opened.
> This heat damage may be visible on the back side of the board where the relay is soldered onto the PCB.
>
> Nest question for Wallies: can you run the fan constantly in the heat mode if using a Nest Tstat and conventional furnace??


I’ll pull the board off and have a look at the back

Eric1973

And we have a winner!

JUGHNE

For us in the business that is the evidence needed to show the homeowner to justify 2 parts instead of just one.

Congratulations

HVACNUT

Where are you located?
There should be a Rheem distributor in your area.
Or Ruud. They're pretty much the same. Just give the model and serial numbers so they can cross reference.
Good job!