Thermostat for a Goodman GMVC95

[kiva55]

Just had a new furnace installed. The installer indicated that he was going to need to do some research since the supplier provided him the latest Goodman model which he wasn't expecting. I read from the Goodman's website that there is a specific thermostat model (ComfortNet) that they recommend with this series of furnace. From my basic research, these appear to be the White Rogers touch screen thermostats. Should I go with the ComfortNet/White Rogers or would the Honeywell IAQ be the way to go? Also had a Aprilaire 600 humidifier installed and have a Lennox AC unit attached.

[amd]

Any 2-stage honeywell, white rogers, or totaline t-stat will work nicely.

Make sure that the installer connects the W2 and C terminals. (Multi-stage control + eliminate need for batteries respectively)

Only get the honeywell IAQ if you have an a/c and would like to slow down the blower to dehumidify. (or if pulling a new wire isn't practical)

[BaldLoonie]

Might as well go with the matching communicating stat to take advantage of all the furnace can do and tell you.

[amd]

Might as well go with the matching communicating stat to take advantage of all the furnace can do and tell you.

Goodman uses communicating stats?

[ChuckHVAC]

Yes that's the C in GMVC95, Gas, Multiposition, Variable (ECM), Communicating, 95%AFUE.

[jopki]

Any 2-stage honeywell, white rogers, or totaline t-stat will work nicely.

Make sure that the installer connects the W2 and C terminals. (Multi-stage control + eliminate need for batteries respectively)

Only get the honeywell IAQ if you have an a/c and would like to slow down the blower to dehumidify. (or if pulling a new wire isn't practical)

My GMVC950704CX was connected to Honeywell TH6220D1010 FocusPro6000 2 stage without touching the C. That should be OK, right? Everything important works OK but I set manually "Continuous FAN ON" it goes to only 300CFM, with factory DIP switch settings (HiCooling profileD). The Spec says it should be 800CFM...? Does C connection to C only eliminate need for batteries?
Any insight?

GMVC950704CX ----------- TH6220D1010 2 stage battery Tstat

R --------------------------- R--- jumper to Rc
C ------ not connected ------ C
G --------------------------- G
W1 -------------------------- W
W2 -------------------------- W2
Y1 -------------------------- Y
Y2 -------------------------- Y2

[rebehanish]

I thought the "C" on the furnace interface board was for the common. When (and if) the 2nd stage kicked in--wouldn't I have a direct short between 24 volt transformer common and W2?
RB

[garya505]

My GMVC950704CX was connected to Honeywell TH6220D1010 FocusPro6000 2 stage without touching the C. That should be OK, right? Everything important works OK but I set manually "Continuous FAN ON" it goes to only 300CFM, with factory DIP switch settings (HiCooling profileD). The Spec says it should be 800CFM...? Does C connection to C only eliminate need for batteries?
Any insight?

GMVC950704CX ----------- TH6220D1010 2 stage battery Tstat

R --------------------------- R--- jumper to Rc
C ------ not connected ------ C
G --------------------------- G
W1 -------------------------- W
W2 -------------------------- W2
Y1 -------------------------- Y
Y2 -------------------------- Y2


On the GMV95, continuous fan is 56% of HI-COOL speed. What is your HI-COOL speed setting?

There is no way to get a continuous fan speed of 300. The lowest is 380 and that's with a blower speed of 600 (1.5 ton cooling unit).

Are you confusing Ramping Profile Tap D with Cooling Speed Tap D?

[rebehanish]

All the batteries do, are to maintain the computer program in a power outage or if you take it off the wall. The batteries that come with any of the honeywell's (I think) are not rechargeable. So change them about every 3.
RB

[ChuckHVAC]

All the batteries do, are to maintain the computer program in a power outage or if you take it off the wall. The batteries that come with any of the honeywell's (I think) are not rechargeable. So change them about every 3.
RB

Unless you don't connect a common wire from the system (terminal C), then the batteries run everything and don't last as long.

[jopki]

On the GMV95, continuous fan is 56% of HI-COOL speed. What is your HI-COOL speed setting?

There is no way to get a continuous fan speed of 300. The lowest is 380 and that's with a blower speed of 600 (1.5 ton cooling unit).

Are you confusing Ramping Profile Tap D with Cooling Speed Tap D?

No confusion there.
56% of HiCool is correct for GMV95.
30% of capability is for GMVC95. (officially but less in reality) I should be getting 480 (0.3X1600 for CMVC950704CX) but am getting 300. Apparently it is an issue that can only be dealt with by using the new communicating thermostats.

[jumpit]

Can you actually get a communicating stat from Goodman yet. I was told they are not avaliable yet, and must be installed in the legacey mode(regular stat)? They will not have outdoor units avaliable with communicating til 2010 sometime.

[spotts]

Any 2-stage honeywell, white rogers, or totaline t-stat will work nicely.

Make sure that the installer connects the W2 and C terminals. (Multi-stage control + eliminate need for batteries respectively)

Only get the honeywell IAQ if you have an a/c and would like to slow down the blower to dehumidify. (or if pulling a new wire isn't practical)

Or if you want it to run the humidifier.....

[garya505]

No confusion there.
56% of HiCool is correct for GMV95.
30% of capability is for GMVC95. (officially but less in reality) I should be getting 480 (0.3X1600 for CMVC950704CX) but am getting 300. Apparently it is an issue that can only be dealt with by using the new communicating thermostats.

Oh, that's kinda funky then ...

[rebehanish]

So if I hook up the "C" terminal at the two stage stat with a sixth wire and hook it to the furnace board at the common--------your telling me I can charge the non-chargeable batteries that come with the 6000 series????????
Sorry, I'm not buying it............
RB

[garya505]

So if I hook up the "C" terminal at the two stage stat with a sixth wire and hook it to the furnace board at the common--------your telling me I can charge the non-chargeable batteries that come with the 6000 series????????
Sorry, I'm not buying it............
RB

No, it won't charge the batteries but the stat will run on transformer power so the batteries will last a lot longer.

[jopki]

Can you actually get a communicating stat from Goodman yet. I was told they are not avaliable yet, and must be installed in the legacey mode(regular stat)? They will not have outdoor units avaliable with communicating til 2010 sometime.

I was also told (Mid Nov.2009) they were not available at the time.

[jopki]

OK, I stated in one of my previous posts that the spec said 800CFM but that is incorrect as I mixed up the specs. It should be 480CFM for GMVC950704CX, confirmed by phonecall to Goodman. Sorry about that.

[garya505]

Are Goodman or White-Rodgers communicating stats available yet?

[mhoy9]

Yes installed one last week interesting not as nice as the infinity or evolution in my mind but very nice for the price

[garya505]

Yes installed one last week interesting not as nice as the infinity or evolution in my mind but very nice for the price

Got a model number or a link to some info on it?

[shoman32]

I installed a Goodman as above last November, with with a Comfortstat two stage thermostat. It seems to me that at the constant on blower setting the air speed is too low,altho I don't have a velocity meter. You can't feel the air coming out of the duct at all...wondering if this is owing to the roughly 360 cfm setting, or if my system isn't performing as it should. Anybody have an opinion?

Also, do the ComfortNet stats allow you to change the constant on blower speed?

Thanks

[garya505]

I installed a Goodman as above last November, with with a Comfortstat two stage thermostat. It seems to me that at the constant on blower setting the air speed is too low,altho I don't have a velocity meter. You can't feel the air coming out of the duct at all...wondering if this is owing to the roughly 360 cfm setting, or if my system isn't performing as it should. Anybody have an opinion?

Also, do the ComfortNet stats allow you to change the constant on blower speed?

Thanks

This problem (constant speed too low) has been reported before, but only when using a conventional stat.

The ComfortNet stat (CTK01) is supposed to allow you to set it to 30%, 50% or 70% of max, though I don't know if anyone has confirmed that.

There was also a Goodman tech bulletin out on this, though you would have to check to see if your unit is affected. There's a fix for it if it is.

Goodman doesn't seem to have their act totally together on the ComfortNet stuff yet, or at least there are some rough edges to be addressed. Using a Goodman ComfortNet furnace with conventional stat and Goodman non-ComfortNet heat pump seems to have some problems, though a non-ComfortNet, straight AC condenser should work OK.

[shoman32]

Thanks for the reply. My stat is a ComfortStat conventional two stage thermostat, I have a converntional AC condensor with my GMVC95 Goodman furnace, and everything seems to be working, after I bridged the Y1 to Y2 connectors on the control board, which is necessary to make the furnace blower operate at the high speed level. Wish I could figure out how to adjust that board to get more speed out of my blower. Even the dealer I bought the furnace from hasn't seen a Goodman ComfortNet therm, so he isn't much help as to it's functioning.

[garya505]

Thanks for the reply. My stat is a ComfortStat conventional two stage thermostat, I have a converntional AC condensor with my GMVC95 Goodman furnace, and everything seems to be working, after I bridged the Y1 to Y2 connectors on the control board, which is necessary to make the furnace blower operate at the high speed level. Wish I could figure out how to adjust that board to get more speed out of my blower. Even the dealer I bought the furnace from hasn't seen a Goodman ComfortNet therm, so he isn't much help as to it's functioning.

The Y1-Y2 connection is clearly shown in the GMVC95 installation manual, so I would be wary any contractor who installed this without noticing that. On the GMVC95, Y1 is connected to Y2 for a single-stage cooling condenser, but not for a 2-stage condenser.

Even without using a ComfortNet stat, GMVC95 blower speeds are adjustable. I would tell your contractor you are not getting enough airflow, and request that they set the blower switch settings to a higher speed that would still be within the allowable range for heat rise. Note that this does not affect the constant fan speed. My guess is that they just left it on the factory settings. It's all in the installation instructions so your contractor should be able to figure it out.

[shoman32]

My installer didn't have experience with the Goodman GMVC95, he relied on the tech at the wholesaler for the setup, and the latter apparently hadn't familiarized himself with the installation manual either. In all other particulars the system seems to be functioning appropriately.

To impose on you hopefully just one more time, I notice that even with the Y1 Y2 bridge my AC doesn't seem to cool the second floor as well as the blower on my old 140,000 btu furnace. Temperature at my floor vents (on AC, single stage condensor, 3.5 ton) runs about 54 degrees F. Does this temperature indicate whether or not the blower is set for the correct CFM?

Thanks,

George