[snappypappy]

So, my contractor installed a 90+ condensing furnace for us when our old furnace crapped out two winters ago. If I'm reading this right, it's a 60k BTU, two-stage induction blower, (Rheem RGRK-06EMAES).

Last year I had the guy add a programmable thermostat, and he got me a really good deal on a Honeywell TH8110U1003. I was trying to figure out the difference between the stat's CIRC and ON modes, when I came across a sales sheet somewhere. The sheet said that my model is a only a 1 heat/1 cool stat! Apparently, there's also 2 heat/1 cool, and 2H/2C (if I remember correctly) models.

So question is, does that stat basically downgrade my furnace to a single-speed, or is the furnace smart enough to still use both high and low fire? Or is it that the stat still sends signals for high/low fire, and the other stat models are for multiple profiles?

Did I just get hosed?

For bonus points, my contractor moved away or went out of business (don't laugh, he was a licensed contractor...he went to my church, but he was young and didn't really know how to run a business). If I do end up needing a different stat, is there a way that I can end up not being out the price of my current one?

 

[geodude]

In a nutshell, no. In order to take advantage of the two stage burners and comfort that two stage offers you really need a two stage stat. There are rheem guys that can help you here but most 2 stage furnaces will time out on first stage after say ten or fifteen minutes, then go to second stage. IF it is wired and dip switches set up correctly. If in doubt, call a local rheem contracter and have them put in a two stage stat.

 

[Twilly]

Twilli agrees get a 2 stage stat.

 

[CDNtech]

Edit:

 

[RyanHughes]

Edit:

Question already answered above.

 

[Twilly]

Twilli thinks 12 minutes, but still get the 2 stage stat.

 

[mayguy]

You are best to go with a two stage stat to get the full comfort of two stage, right now (if it's wired right) it will go on a timer and time out 1st stage, and go into 2nd.

If you don't have enough wire in the wall, then may have to stay with this, or upgrade to the Honeywell IAQ stat.

 

[geodude]

You are best to go with a two stage stat to get the full comfort of two stage, right now (if it's wired right) it will go on a timer and time out 1st stage, and go into 2nd.

If you don't have enough wire in the wall, then may have to stay with this, or upgrade to the Honeywell IAQ stat.

The 9000 IAQ honeywell rocks!!

 

[beenthere]

You may be able to donate your current thermostat to your church.
And then take a tax deduction for it. Other then that, not much of a market for used stats.

 

[bobb25]

You are best to go with a two stage stat to get the full comfort of two stage, right now (if it's wired right) it will go on a timer and time out 1st stage, and go into 2nd.

If you don't have enough wire in the wall, then may have to stay with this, or upgrade to the Honeywell IAQ stat.

I have heard that the Carrier Totaline P474-0410 and/or the Venstar ACC0410 add-a-wire thermostat relay will allow 4 wires to work like 5 wires & 5 wires to work like 6 wires. Can't be sure, never used them.

 

[bobb25]

Did I just get hosed?

For bonus points, my contractor moved away or went out of business (don't laugh, he was a licensed contractor...he went to my church, but he was young and didn't really know how to run a business). If I do end up needing a different stat, is there a way that I can end up not being out the price of my current one?

The best way to get your money back, is to find the original guy, politely explain the problem, and ask him. Being a church going/god fearing religious person, I'm sure he will have not problem refunding all your money.

Whatever you do, don't insult the new company by asking them to give you money back for a used thermostat. Give it back to the original guy after he refunds all your money.

 

[snappypappy]

Thank you for the input, you guys are awesome. Just to be sure that I understand you correctly, you're saying that my setup can't call for low-fire, so the furnace is only going to use the second stage as part of a built-in timer profile (assuming the dip switches are set correctly, and I guess that's a crapshoot if this fella didn't know to put in a two-stage stat). Do I have it right?

I also noticed that Honeywell had a humidistat version of the 9000. I have a AprilAire humidifier, but the guy just wired an analog stat into the return above the humidifer. Would I need some external sensor for a humidistat to work, or is it another issue of the amount of wire going into my wall?

I'm gonna call a local contractor, but I may as well take a look behind the stat and see how many wires I have. Off the top of my head, I recall 5 or 6, but that could be off. How many would I need for a regular 2-stage stat and/or with a humidistat?

Oh yeah, and I wanna stress that I have a PSC, not an ECM. Does that make a difference?

 

[second opinion]

Thank you for the input, you guys are awesome. Just to be sure that I understand you correctly, you're saying that my setup can't call for low-fire, so the furnace is only going to use the second stage as part of a built-in timer profile (assuming the dip switches are set correctly, and I guess that's a crapshoot if this fella didn't know to put in a two-stage stat). Do I have it right?

I also noticed that Honeywell had a humidistat version of the 9000. I have a AprilAire humidifier, but the guy just wired an analog stat into the return above the humidifer. Would I need some external sensor for a humidistat to work, or is it another issue of the amount of wire going into my wall?

I'm gonna call a local contractor, but I may as well take a look behind the stat and see how many wires I have. Off the top of my head, I recall 5 or 6, but that could be off. How many would I need for a regular 2-stage stat and/or with a humidistat?

Oh yeah, and I wanna stress that I have a PSC, not an ECM. Does that make a difference?

Your system will run in both first and second stage if there is a jumper between W1/W2. Most mfg. design the units to use either 1 or 2 stage Tstats. Depending on where you live and the thermal value of your house you may not have any problem at all with the single stage Tstat it may satisfy in first stage and never need second stage.

The IAQ if you decide to use only requires 3 wires at the Tstat location.

 

[mayguy]

I also noticed that Honeywell had a humidistat version of the 9000. I have a AprilAire humidifier, but the guy just wired an analog stat into the return above the humidifer. Would I need some external sensor for a humidistat to work, or is it another issue of the amount of wire going into my wall?

Being that your furnace is a standard blower, and have enough wire in the wall. (need up 6, or 5 and run on battery), the IAQ (900) is kinda over kill since you do have a good humidistat on the return arleady.

 

[bobb25]

Your system will run in both first and second stage if there is a jumper between W1/W2. Most mfg. design the units to use either 1 or 2 stage Tstats. Depending on where you live and the thermal value of your house you may not have any problem at all with the single stage Tstat it may satisfy in first stage and never need second stage.

The IAQ if you decide to use only requires 3 wires at the Tstat location.

I believe the Honeywell TH8110U1003 has C,R,Rc,W,Y,G,O/B,S1,S2.

 

[jpb2]

The ugrk with a single stage stat i believe will run @75% for 15 minutes and then full fire until the stat is satisfied.

 

[printmanjackson]

to answer the original question, yes you do

 

[diverus]

some units like the goodman/amana have dip switches to set it for two stage. It will run for five minutes in first stage,then it will open up for second stage. also the lennox units have a jumper to set single or two stage. that will work if you don't have a two stage t-stat or enough wires.

 

[second opinion]

to answer the original question, yes you do

And how did you come to this conclusion?

 

[beenthere]

to answer the original question, yes you do

No, you don't need a 2 stage stat to use, or have 2 stages of heat from the furnace.
Don't know off hand of any 2 stage furnace that doesn't have a timer to go to second stage if you use a single stage stat.

But, you get better comfort if you have a 2 stage stat.