What is a two stage thermostat?

[bebba1]

I saw an earlier thread from someone indicating with a two stage gas valve, you should get a two stage thermostat. This relates to the Trane XL 1400 model.
Is everyone fairly firm that the variable speed drive is worth the extra 1000 USD in Kentucky/Tennessee? I wonder how much the yearly savings are versus a fixed speed/single stage gas valve.

[beenthere]

A 2 stage thermostat will control weather the unit is in first stage, or second stage, not a timer.

The VS blower is more for comfort then savings.
But does save some money on electric to operate it, and some people can set their stat alittle higher because of the better humidity control.

[alexb]

Does a variable speed AH require a special thermostat? --Any fancier than the best Honeywell model you can pick up at Home Depot?

(Has switches for Fan on/off and Heat/Off/Cool on the other side?)

I have a new Honeywell model I just installed myself. Now I find my 19-year old Carrier has died. Can my new Honeywell unit be used with a new vari-speed AH?

[beenthere]

Yea, your stat will be ok for it.

But there are stats that can slow down a VS blower to aid in dehumifying, by slowing down the blower.

[alexb]

Ah! Are you saying that my AH's blower speed will not change, without a 'special' TStat? Is it the TStat that slows the blower, or circuitry inside the AH itself?

[dan sw fl]

Originally posted by bebba1
This relates to the Trane XL 1400 model.
Is everyone fairly firm that the variable speed drive is worth the extra 1000 USD in Kentucky/Tennessee? I wonder how much the yearly savings are versus a fixed speed/single stage gas valve.

XL16i Heat Pump will be a much better, economical solution for yearly energy costs for KY.

[beenthere]

Originally posted by alexb
Ah! Are you saying that my AH's blower speed will not change, without a 'special' TStat? Is it the TStat that slows the blower, or circuitry inside the AH itself?

Yes, in order to slow the blower down, either a humidistat, or a thermostat designed to slow the blower down is required.

[wiwbar]

In the Honeywell Visionpro 8000 series, the 8110 is for "1 heat and 1 cool stage". The 8321 is for up to "3 heat and 2 cool stages". As I have a 2 stage system, I would assume I want the 8321 as the 8110 would not fully utilize the 2 stage system? Thank you very much

[mayguy]

Originally posted by wiwbar
In the Honeywell Visionpro 8000 series, the 8110 is for "1 heat and 1 cool stage". The 8321 is for up to "3 heat and 2 cool stages". As I have a 2 stage system, I would assume I want the 8321 as the 8110 would not fully utilize the 2 stage system? Thank you very much

The 8321 will control two stages. if you have a two stage heating and/or cooling.

Some brand has a control of their own built in to help with better humidity removeal like Trane's "Comfort-R" control that the install set up on start up.

The 8110 will only do a single stage system.

[wiwbar]

Thank you for the quick reply.

[alexb]

I checked with the company that I got a quote from, and they said circuitry internal to the AH controls the RPMs of the blower; not the TStat. (Thermistor)

However: If you have a 2-stage or 3-stage heat/cool system, then a special TStat is requird.

What I'd have, will be a single-stage A/C-only system, with a vari-speed AH. With this, I was told that the nice $50 Honeywell Tstat I installed will be just fine. (Digital, programmable)

[seatonheating]

Originally posted by alexb
I checked with the company that I got a quote from, and they said circuitry internal to the AH controls the RPMs of the blower; not the TStat. (Thermistor)

However: If you have a 2-stage or 3-stage heat/cool system, then a special TStat is requird.

What I'd have, will be a single-stage A/C-only system, with a vari-speed AH. With this, I was told that the nice $50 Honeywell Tstat I installed will be just fine. (Digital, programmable)

Just make sure they do the wiring in the AH properly. I see it done incorrectly all the time.

[beenthere]

Originally posted by alexb
I checked with the company that I got a quote from, and they said circuitry internal to the AH controls the RPMs of the blower; not the TStat. (Thermistor)

However: If you have a 2-stage or 3-stage heat/cool system, then a special TStat is requird.

What I'd have, will be a single-stage A/C-only system, with a vari-speed AH. With this, I was told that the nice $50 Honeywell Tstat I installed will be just fine. (Digital, programmable)

Then they forgot that some stats have the humidistat control built in to them that will slow the blower down.

But you can use the stat you have. It just won't slow the blower down.