Wiring 2 stage thermostat

[thesober]

I just got a two stage furnace installed, the installer hasnt installed a two stage thermostat yet because they were out of stock. He will come back later.

My question is...Can the old one stage thermostat wires be used for the new two stage thermostat? Or do they have to run new wires?

[billva]

they will need one extra wire for proper wiring of a two stage. if you have an extra wire in the bundle, no problem. if not, then yes they will need to run a new wire.

make sure they actually put up a two stage stat if that is what you paid for. (and i hope you did). they can wire a single stage t-stat, which will control the stages via a timer. although workable, not the way to go for maximum comfort.

good luck.

[thesober]

I paid for a two stage thermostat, they brought over a single stage one and i caught it before they did the installation. I refused that and they will come back to do the two stage install.

[smokin68]

Can't the furnace control the stages? Might not need a 2 stage stat, just depends on wiring. Should get the difference back though......didn't order the nice Visionpro with your new system?

[wyounger]

Yeah, what billva said. Fine for limping along while waiting for the right thermostat to come in, or for the new thermostat wire to be fished, but don't leave it that way permanently.

Furnace-controlled staging is a travesty. Don't cripple the comfort-producing ability of nice multistage systems with inferior controls because of something so simple as a wire not having enough conductors. The only way to control staging well is to do it based on demand, and only the thermostat knows how much demand is actually present.

[thesober]

Ok guys, I need some help. I got my two stage thermostat installed (Honeywell FocusPro TH5220D), My installer installed it without running new wires.

I think he just installed it as a one stage thermostat, so i opened it up to see what wires were connected and here is what i found (5wires only). G,W,C,Y,R-Rc were connected. Y2,W2 were left empty. Can anyone shed some light if he connected it correctly to optimize 2 stage function of my thermostat with my 2 stage furnace?

I seached around the forum and it leads me to believe that there needs to be a wire connected to W2, is this correct?

If it makes a difference, my furnace is a Carrier Performance93.

[smokin68]

That's hooked up like a single stage. Spend the extra $$$ for a Visionpro, not that Focus stat. Right now the furnace is controlling the stages.

[nord 64]

2 stage furnace 2 stage T-stat

I converted myself ran for 3 weeks on single t-stat 2 stage t-stat made a big difference for me. I use setback a lot and with a two stage T-stat the furnace will run in the second stage right away, rather than limping along in the low fire stage for 10-15 min.

[thesober]

Thank for the confirmation.

So i'm assuming that he has to run new wires in order for it to be correctly installed?

My parents told me that the installer wanted more $$ for new wires. I mean i paid for 2 stage furnace and 2 stage thermostat. Shouldnt that be included in the price? Am I getting duped?

[smokin68]

If you paid for 2 stage stat, and they need to run new wires for 2 stage stat, that's not your fault/problem. That's THEIR problem.....don't pay any extra,or you are getting dupped.

[Edited by smokin68 on 01-11-2006 at 08:26 PM]

[nord 64]

I agree with smokin68, they should have checked the wires...their fault, do not pay an extra cent.
IMHO

[beenthere]

I thought the 5000 series could use batteries, if so, and you have 5 wires, don't need to pull any more, just don't use common.

[thesober]

Originally posted by beenthere
I thought the 5000 series could use batteries, if so, and you have 5 wires, don't need to pull any more, just don't use common.

Thanks for everyones help. I called the company and told them that the installer installed it as a one stage thermostat and that the installer wanted more $$ for new wires. They are going to talk to the installer. Ill post again to see what they say. Without you guys i would assume everythign was ok and paid fully. A big thanks again!

Can i ask why the common wire shouldnt be used, just in case they try to use that wire? The manual does say that the common wire is optional if using batteries. I dont see any other wires that he could use from the G,W,C,Y,R-Rc lineup.

[smokin68]

If you want to have batteries to replace, let them use the common wire to control your second stage.With the common wire installed, your t-stat is powered by the furnace's transformer(no batteries needed,unless for back-up). Just tell them to run new wire,and hopefully they're smart enough to use 8 strand minimum,to help if a future problem occurs( wire shorted,etc.)

[thesober]

UPDATE:

Ok guys, i had the company send the installer back to wire it properly. Luckly they sent another installer so i got a 2nd opinion on the furnace install. He said it was good and fixed some minor spots that were missed...like missing screws.

Anyways when he was looking at the wiring, he found out that the wiring had 6 wires so new wiring wasnt needed. (Damn lazy first installer) All i wanted was to have a two stage thermostat wired properly so all is good.

Question: How do i know if its the furnace or thermostat that is controlling the first and second stage? When the tstat was installed as a single stage, it started on low and then high heat came out after a while. What should i look for now?


Thanks again for everyone who posted and helped me out.

[seadragon]

thesober,

With a 2 stage stat, you should now notice a couple of thing (both of which a single stage stat is not capable of):

1. The furnace should run a looooong time in low stage on milder days. It should rarely come up to high stage unless its really cold and windy or coming out of setback. This is the number one difference you will notice. With a single stage stat the furnace is limited by a timer to run in low stage for up to about 16 minutes or so. Then it will always go to high stage.

A 2 stage stat senses the rate at which the temp is changing in the room and will kick the furnace into 2nd stage ONLY if required. My furnace will sometimes run in low for over an hour before shutting off.

2. Your 2 stage stat will now allow the furnace to run in Low, then go to High (if needed) then BACK TO LOW again. A single stage will only go from Low to High then OFF. This may not be as obvious unless you are sitting around timing the stages on the furnace..

And yes, I'm a geek. I have sat around and monitored my furnace. I have no life!

[refinished]

Glad I found this thread. I just had a Carrier 58CTA installed. Among some other issues with the installation, I noticed that the furnace only seems to burn at one level of fire. I looked at the wiring on the two-stage capable thermostat (Totaline P474) and the screw labeled W2 is not attached to anything. They pulled a new 5-wire bundle. From what I am reading here - five wires is not enough to support thermostat controlled staging when the thermostat has no batteries. Can someone confirm this before I explain to the installer why he can't have any money just yet?

Also - Given that it appears to be set up as a single stage, why would the furnace not be burning low for some period and then burning high? Is that not what it is supposed to do? I sat next to the thing for 15 minutes after it kicked on - it made the same amount of noise and the pitch didn't change at all.

[patterack]

W1 and W2 may be jumped at control board resulting in full time high fire.