Incorrect wiring?

[robbieas]

I recently bought a new house, but under foreclosure so I can't call the builder because they are out of business. The house was 100% complete and the AC worked great all summer. The heat has worked fine up until recently when it go really cold, but now it's doing some funny stuff. I suspect there is some incorrect wiring.

BMPlus 3000
3 Zones - Hunter programable thermostats (1 cool, 1 heat)
Heat pump w/ electric 2nd stage (I think, there is no gas to the house, everything is electric, so it should be electric 2nd stage)
Location: Atlanta, GA (for outside temp idea)

Where the system is wired in (bottom left of panel), I have wires connected to both the O and W1/B contacts - I don't see in the manual any configuration that would have the system wired to both of these terminals. Nothing is on W2/E. Doesn't this seem wrong?

The SAS appears to be wired incorrectly. The two leads are connected one to the top SAS contact and one to the bottom OAS contact. Shouldn't they be wired to the two SAS contacts only?

The heat works fine at first for a while. It worked fine when it wasn't very cool out, it never ran more than 20 minutes or so to heat the house. Now that it is much colder out it seems to cut out perhaps when the 2nd stage is supposed to cut on. After a while (I haven't timed it) only cool air blows. I can turn all of the thermostats to off, and the LED's indicate both heat stages are off, and the fan is off. But the fan is running. If I kill all the system breakers, turn the back on, everything works fine again for a while.

Any thoughts here? My thought is the there a problem when the 2nd stage comes on. I suspect the system isn't wired correctly, and perhaps the SAS is also wrong.

Thank you for any help you can provide!



Regards,
Robbie

[Eric K.]

Robbie,

It seems as if the system is indeed wired incorrectly.

On the system output, the backup heat should be wired to the W2/E terminal and not the W1/B terminal.

For the supply air sensor, it should be wired to the two designated SAS terminals, but believe it or not it would work properly the way it is. (Both the bottom SAS and bottom OAS terminals are ground).

You may also have some dip switches set incorrectly. How are all of the switches set?

Eric

[robbieas]

First, thank you so much for replying to my post. It's amazing that you guys operate such a helpful forum. Your reply saved me a service call, which I'm sure would have cost me $75 at a minimum. I owe you a beer.

I moved the system backup heat to the correct terminal, and I'm pretty sure that solved the problem. I'll know for sure in a day or two, but everything already appears to be functioning correctly. I also moved the SAS to the SAS ground terminal, although as you mentioned it would work correctly either way.

I think the dip switches are correct, but if you could give me your feedback on them that would be awesome.

DIP SWITCHES
1: Left
2: Right
3: Left
4: Left
5: Right
6: Left
7: Right
8: Left

POTENTIOMETERS
Staging Timer/OAS: 30
Low Temp Limit: 49
High Temp Limit: 150
2nd Stage Heat Differential: 33

Emergency Heat Switch: NORM

Anything here look out of place?

[Eric K.]

Robbie,

Sorry for the delay in my response.

All of the dip switches are in the correct place. The only thing I suggest changing is the 'High Temp Limit', I suggest setting it for about 130°F.

Happy New Year!

Eric