wiring two stage condesor ASXC18 help please

[kingkaiko2002]

Hi everyone,

Just installed a goodman two stage condensor ASXC18. I only have two wires from the Circuit board to the condensor, I am unable to run new wires. Called goodman tech and they said to use Comfortnet T-stat and add a transformer to power R and C and uses the two t-stat wires for Y1 and Y2. The problem is that the price of comfortnet T-stat. It's pricy. are there any other T-stats that will do the job or am I stuck? Will the emerson touch screen do the job?

Thanks

[SBKold]

Get the stat.

Its worth it. Imo.

It makes troubleshooting much much easier.

[vibration]

Faststat

[jimj]

Get the stat.

Its worth it. Imo.

It makes troubleshooting much much easier.

I agree, or you can do this.
http://jacksonsystems.com/view_product/26828

[kingkaiko2002]

Faststat

Cool thanks,
oh yea, I've heard about it but never think about it. This seem a little bit less expensive than going with comfortnet. Currently, it has an emerson touch screen, which to me is good enough.

[mgenius33]

I'm not a fan, but I've seen the refer tubing used for common, with the common of the tx bonded.

[ga-hvac-tech]

I'm not a fan, but I've seen the refer tubing used for common, with the common of the tx bonded.

I do not like this either... however it does 'work'.

I would get a wire doubler (faststat or Jackson, as noted above).

[kingkaiko2002]

Yea, I've heard of people doing this too, but for what the customer is paying for, and because of 10 years part and labor warranty. I would rather use faststat. Call back is not worth.


I do not like this either... however it does 'work'.

I would get a wire doubler (faststat or Jackson, as noted above).

[SBKold]

The furnace is a communicating model correct?

[kingkaiko2002]

yep


The furnace is a communicating model correct?

[mark beiser]

Personally I'd recommend going with the transformer to power the outdoor unit's board, and the communicating thermostat connected to the 2 communications terminals in the outdoor unit.

If you just really don't want to do that, all you "need" if you want to use the existing thermostat is a transformer, two SPST 24v relays, and properly grounded indoor and outdoor units.
Install the transformer in the outdoor unit to power the control board there.
Install both relays in the outdoor unit too.
Run a wire from one side of the coil of each relay to ground.
Run wires from the 24v "hot" side of the transformer to one of the terminals for the contacts on each relay.
Run a wire from the other side of the contacts on one relay to Y1 in the outdoor unit, and a wire from the contacts on the other relay to Y2 in the outdoor unit.
Use the 2 thermostat wires for Y1 and Y2 from indoors to energize the relays for Y1 and Y2 in the outdoor unit.

The relays are to avoid any phasing issues between the indoor and outdoor units transformers.

Like this:
http://www.markbeiser.com/HVAC/randomstuff/junk/2wire2stage.png

It is a more reliable setup than using a faststat or the wireless stuff.

[kingkaiko2002]

Thanks mark,

This is something new. Never think or heard about this. Would love to try it.


Personally I'd recommend going with the transformer to power the outdoor unit's board, and the communicating thermostat connected to the 2 communications terminals in the outdoor unit.

If you just really don't want to do that, all you "need" if you want to use the existing thermostat is a transformer, two SPST 24v relays, and properly grounded indoor and outdoor units.
Install the transformer in the outdoor unit to power the control board there.
Install both relays in the outdoor unit too.
Run a wire from one side of the coil of each relay to ground.
Run wires from the 24v "hot" side of the transformer to one of the terminals for the contacts on each relay.
Run a wire from the other side of the contacts on one relay to Y1 in the outdoor unit, and a wire from the contacts on the other relay to Y2 in the outdoor unit.
Use the 2 thermostat wires for Y1 and Y2 from indoors to energize the relays for Y1 and Y2 in the outdoor unit.

The relays are to avoid any phasing issues between the indoor and outdoor units transformers.

Like this:
http://www.markbeiser.com/HVAC/randomstuff/junk/2wire2stage.png

It is a more reliable setup than using a faststat or the wireless stuff.

[mark beiser]

Thanks mark,

This is something new. Never think or heard about this. Would love to try it.

I came up with it a couple of years ago when I needed to run a Trane XL20i condenser off 2 control wires and couldn't use the communicating thermostat because the system was zoned with a non communicating zone control, and running a new control wire was not particularly viable.

It has been working great.

[Kerplacknia]

Hey Mark. How many have you run like that and is there any issue with the relays popping

[mark beiser]

Hey Mark. How many have you run like that and is there any issue with the relays popping

I've only done 2 like that, and no relay issues, but it was only about 2 years ago.

Why?

[Kerplacknia]

Just curious. Its a good idea that i wish I would have thought to do a couple times.

[mark beiser]

Just curious. Its a good idea that i wish I would have thought to do a couple times.

And here I thought you were about to drop the hammer of some electrical phenomena that I hadn't considered!:Faint:

I first came up with it during a Saturday install of a XL20i system with an existing zoning setup, so I had to find a solution with only what was on hand in my service van, and didn't involve running a new wire, which would have been most of a full day job for 2 people.

The 2nd time was a similar deal with an existing zone control system, but just pure lazy on not running a new control wire. :o

[Kerplacknia]

Nah. No electric phenomenon I will say with some Lennox air handlers with hot water heat decks I have seen some crazy back feed pulling condensors on in the winter or back feed through the aqua stats keeping the motor on. I was just curious sometimes those ideas born from necessity are incredible and then some turn into a nightmare I def like that one though.