is this right?

[NDIrish147]

I recently had a dual fuel system installed rgtm07erbgs furnace and upql-030jez HP. The problem i am having is the installer cannot seem to get the IAQ thermostat wired up correctly. from what i understand he should be able to wire the stat up to dehumidify my house but he does not have any wires running to the odd or the y1 terminals on the furnace. He has dipswitches 6 and 12 on and the rest are off. is this correct?

[BaldLoonie]

I wouldn't use Y1, I'd use ODD. It is very simple though I'm not sure I can give step by step info on here.

Switch 6 sets it to 1000 CFM for cooling speed, that's good. 12 has set it for ODD so he got both of them right. Just needs to work on the low voltage wiring and turn dehumidify on using the advanced setup of the IAQ. If he can't figure out what to do, my contact info is in my profile, I'd be glad to assist him with how I wire ODD.

[NDIrish147]

Thanks for the reply BaldLoonie... He is at least close! I thought the switches for dehumidify were 10 and 11? I have read the stinking manual so many times I am having dreams about it right now it is set to cool up to 3* to dehumidify but it never kicks on the low blower speed

[BaldLoonie]

Exactly, I just caught that and was heading back in to correct myself.

#11 needs to be on for ODD, #12 on for 1 stage cool.

I think it is #379 on the IAQ that has to be set to 1 for ODD. And the appropriate wiring between the equipment module and the ODD terminal. Very easy but not sure I can spell it out here.

[NDIrish147]

I think I can show him how to wire the rest from the manual... Thank you! I have another non wiring related question to all of this. My house is a 2000 sqft ranch on a crawl. I have a single 16" flexible return and a 10x22 plenum with 11 6" flex supply lines. The contractor thinks i should upsize my return.... does that sound correct?

[BaldLoonie]

You are on the light side of things. What are you using for a filter? Has the dealer taken static pressure readings to see how they look?

[NDIrish147]

Light side? I had him install a 4" deep pleat filter I believe it is 21" wide. No static pressure readings that i know of.

[motoguy128]

Light side? I had him install a 4" deep pleat filter I believe it is 21" wide. No static pressure readings that i know of.

I think he means the return plenum is a little small, but not bad. Probably a little bigger, like 12X24 would be better. The velocity is around 700FPM for the furnace on high. Which is marginal. Better if it was a little bigger, maybe 12x25". that would also make it a simpler transition to a 20X25" media filter... which I suspect you have. The housing is probably 21" tall, the the filter itself is 20".

[NDIrish147]

would it be effective to run and 18 or 20" flex to a first return and then continue on with my 16" to a second return?