Lennox Thermostats

[ksspartan]

I plan on having a Lennox G60UHV 80% two stage variable speed furnace and a XP19, 2 stage compressor, 4 ton heat pump installed. Two thermostats have been proposed. One is the X4147/X4148 (Honeywell Vision Pro) and the other is a 81M28 which is the Lennox Signature Stat. Which way should I go and why? Would you recommend otherwise if I decide to go with the G61MPV 94% furnace.

[t527ed]

signiture stat "talks" to lennox v drive furnaces for humidity control on a/c unit. not sure honeywell stats can do that.

[ksspartan]

Thanks for the feedback. Are there other difference that I should be considering. Humidity control is important and if all else is equal I would go with the Lennox Signature stat. I just hear so many people on this site talk about the Vision Pro as being the state of the art but I also want to use the stat that is able to take advantage of all the features Lennox has to offer on this upscale highly efficient system that I am paying extra for.

[t527ed]

not sure if vision pro can do anything that sig stat cant. main difference is vision pro touch screen.

[ksspartan]

The contractor that is proposing to install the Vision Pro Stat claims there are problems with the Signature Stat that they prefer the Vision Pro. Any thoughts from anyone that is familiar with the two stats.

Another thing that occurred to me is that if the stat has 3 stages of heat and 2 stages of cooling that works fine for my heat pump system that has a two stage compressor but for heating when I have a two stage furnace and a two stage compressor don't I need 4 stages of heating????

[ksspartan]

Let me rephrase the second part of my questions. It appears that 2 stages of cooling seem to be adequate but 3 stages of heat may not be. It seems like I would need 4 stages of heat?????

[Milk man]

Is this a dual fuel setup?

[mopar guy]

Originally posted by t527ed
not sure if vision pro can do anything that sig stat cant. main difference is vision pro touch screen.

I thought I was understanding that the sig stat is not programable? I'm looking at doing a similiar equipment install & was wondering the same thing.

[ksspartan]

Yes, it will be dual fuel system. I am using a two stage electric heat pump with a two stage, variable speed furnace.

[t527ed]

Originally posted by mopar guy

Originally posted by t527ed
not sure if vision pro can do anything that sig stat cant. main difference is vision pro touch screen.

I thought I was understanding that the sig stat is not programable? I'm looking at doing a similiar equipment install & was wondering the same thing.


sig stat can be programed to do just about anything except turn on coffee pot in the morning. don,t know about duel fuel set ups we do not do heat pumps

[wyounger]

To do it right you do need a thermostat that can control four stages of heating. The VisionPro definitely won't. I don't know about the Lennox either way. Not to say that you can't do this job with with a three stage thermostat, but that leaves the furnace to decide on its own whether it should be on high or low, which isn't ideal. You can also do it with a three stage thermostat and a fossil fuel kit, but that has its own drawbacks (incomplete defrosts, does fuel selection by outdoor temp while ignoring the amount of demand for heat, nearly negates the ability of programmable thermostats to intelligently recover from setback periods).

Carrier's Thermidistat definitely will control all four stages internally. It should also be able to call for the dehumidification function available in the VS furnace during cooling season.

Unless somebody is certain that the Lennox can do four stages, the thermidistat would be my pick.

[Edited by wyounger on 10-19-2005 at 10:03 AM]

[ksspartan]

Doe this Carrier stat also have a humidstat to slow down the VS motor in high humidity conditions?

[wyounger]

Yup. That's why they call it the thermidistat.

[mopar guy]

I had the contractor over tonight & I asked him if the Signature stat has 3 or 4 stages of cooling & he said 3. He said if I were to go with a 2 stage h/p, he would recomend the Carrier stat & there was another one that I can't remember the name of. Otherwise, he said they set them up on a timer for the second stage in the furnace. I've seen that mentioned here before.

[ksspartan]

Thanks Mopar Guy. I believe you meant 3 stages of heat and 2 stages of cooling. I received a call from the from the regional Lennox field guy and he confirmed the same thing you found out. The Signature Stat (81M28)designed for heat pumps does have the ability to control a variable volume fan for humidity control in the summer which is a nice feature. The Honeywell Vision Pro that Lennox also sells with their logo on it has the 3 stages of cooling but no ability to control humidity. The other stat I believe you were referring to other than the Carrier Stat is the White Rogers 1F95-391.

The more I learn about the dual stage compressor heat pump the more I am starting to lean away from it. This option is quite costly and is only for comfort rather than efficiency. I'm not sure I will see a large difference in comfort when its all said and done. I think the variable volume fan will play a bigger role in that.

[wyounger]

You are well on your way to being a Master, Obi-Wan.