[LouisB]

Our heat pump contractor recently replaced their first thermostat with a Totaline Model P286-1500, setup for 1 Stage Cooling/ 2 Stage Heat. The O/B/W goes to HP Changeover Valve, Y1 to HP Comressor and W2 to Oil Furnace. This results with HP being off it's heating cycle while Oil Furnace is on. This setup works well but the temperature never matches setting.. at best 1 Celsius (1.8F) degree up or down from setting (sometimes 1.5C). Thermostat is specified at +/- 1 degree accuracy. The previous thermostat they installed (Honeywell TH611) proved unsuitable for a dual heat system, but controlled either source (HP or oil) right on setting.
Is there a thermostat available that can do the job of maintaining a comfortable temperature? Any recommendations?
Thank you...

[KISS]

The Vision Pro Series from Honeywell is getting a lot of attention these days:

Check out: http://www.iaqsource.com/search.php?...it_continue=Go

[LouisB]

The Vision Pro Series from Honeywell is getting a lot of attention these days:

Check out: Search | iaqsource.com - Aprilaire, Honeywell, Trion Air Bear, Bryant, Carrier, Trane Filters and IAQ products

OK, but I am hoping for some guidance in selecting a correct thermostat. Do you work for Honeywell? If yes then maybe you can confirm if their VisionPro8000 (Model for a 2 Heat/1Cool System) allows the Heat Pump to work while the Fuel Heat (Emergency Heat) comes on? That is a No-No situation... sooo, where do I get this info on Honeywell's site as it does not appear in their instruction sheets. The technician does not recommend this thermostat for the above reason.
Thank you

[KISS]

I looked at the installatiion instructons under the File menu and there is an auxiarry locout and a heat pump lock out temperatures that can be set. This would ensure that the HP can't be on when using aux heat. This would require the installation of an outdoor temperature sensor. Without this sensor, you don't have any "lockout police". AUx and HP mode is determined by outside temperature with some amount of hysteresis.

The top end model makes installation a snap, because all of the contacts are at the furnace and only a few wires (I think 3) are needed for all the functions. I believe that the temperature sensor must be run from the thermostat.

Look here: http://www.ntsupply.com/files/produc...stallation.pdf

At the installer options 0350 and 0360.

I didn't look, but this guy should be able to do it too: YTH9421C1002: $199.00 | Honeywell VisionPro IAQ Programmable MultiStage Thermostat with Total Home Comfort Control | iaqsource.com - Aprilaire, Honeywell, Trion Air Bear, Bryant, Carrier, Trane Filters and IAQ products

It's easier to wire and I think you give up arm chair programming. Not sure.

[LouisB]

I looked at the installatiion instructons under the File menu and there is an auxiarry locout and a heat pump lock out temperatures that can be set. This would ensure that the HP can't be on when using aux heat. This would require the installation of an outdoor temperature sensor. Without this sensor, you don't have any "lockout police". AUx and HP mode is determined by outside temperature with some amount of hysteresis.

The top end model makes installation a snap, because all of the contacts are at the furnace and only a few wires (I think 3) are needed for all the functions. I believe that the temperature sensor must be run from the thermostat.

Look here: http://www.ntsupply.com/files/produc...stallation.pdf

at the installer options 0350 and 0360.

I didn't look, but this guy should be able to do it too: YTH9421C1002: $199.00 | Honeywell VisionPro IAQ Programmable MultiStage Thermostat with Total Home Comfort Control | iaqsource.com - Aprilaire, Honeywell, Trion Air Bear, Bryant, Carrier, Trane Filters and IAQ products

It's easier to wire and I think you give up arm chair programming. Not sure.

Looked at document (although Commercial version of VisionPro) and Fig.27 is as you mention regarding lockouts but also shows that "Both Compressor and Auxiliary Heat operate between the lockout settings". Now at this point do I conclude that the thermostat logic only operates one heat source, and not both simultaneously? Note that my system's control circuit has an interposing relay to open the compressor's "Y" circuit wire when an outdoor -12C switch activates such relay coil. Sorry for being persistent with this question... the compressor is at stake.

[KISS]

So, your compressor can't work at -12C, done deal.

Look at page 8, option #0, setup function 0345. I think this is what you want.

You may want option #2 though. I interpret this as both won't operate at the same time and if room temperature doesn't warm fast enough, you use backup heat. In other words, it always tries to use the HP unless it's locked out.

Heat Pump Control — Fossil Fuel Backup (Setup Function 0345):
Option 0 (Balance point only): If outdoor temperature is above balance point (Function 0350),
Only the compressor operates. Below this temperature, only backup heat operates.

Option 1 (Balance point + 2°F droop): As above, but backup heat is activated if room temperature
Drops by 2°F (compressor is deactivated).


Option 2: (Balance point/Aux Heat +2°F droop): Compressor works only above auxiliary lockout
Temperature, backup heat works only below balance point, 2°F droop between temperatures. If
Temperature is not reached in a reasonable time, set the upstage timer (Function 0346). After
The designated time, the compressor will be deactivated and the system will switch to backup
Heat.

[LouisB]

So, your compressor can't work at -12C, done deal.

Look at page 8, option #0, setup function 0345. I think this is what you want.

You may want option #2 though. I interpret this as both won't operate at the same time and if room temperature doesn't warm fast enough, you use backup heat. In other words, it always tries to use the HP unless it's locked out.

Heat Pump Control — Fossil Fuel Backup (Setup Function 0345):
Option 0 (Balance point only): If outdoor temperature is above balance point (Function 0350),
only the compressor operates. Below this temperature, only backup heat operates.

Option 1 (Balance point + 2°F droop): As above, but backup heat is activated if room temperature
drops by 2°F (compressor is deactivated).


Option 2: (Balance point/Aux Heat +2°F droop): Compressor works only above auxiliary lockout
temperature, backup heat works only below balance point, 2°F droop between temperatures. If
temperature is not reached in a reasonable time, set the upstage timer (Function 0346). After
the designated time, the compressor will be deactivated and the system will switch to backup
heat.

Contractor today came in with and installe a VisionPRO 8000 Model TH8320U1016 (version for Canada... probably due to need in Celsius readings). Tried locating installation instructions from Honeywell's site but no success... I remain with the doubt that the HP will be turned off if the thermostat turns on the auxiliary fuel heat... will have to hold my hand on the gas line at the evaporator entrance to verify if remains hot when furnace kicks in (evap is located in the forced air plenum above the fuel heat source).
Tried to follow your most recent explanation but could not locate referenced detail in document to which you provided link in earlier response. Well thank you so much for the assistance... will continue to research this question somehow, and possibly have something to report here soon.

[KISS]

What's so hard:

TH8320U1008: $139.95 | Honeywell VisionPro 8000 Programmable MultiStage Thermostat | iaqsource.com - Aprilaire, Honeywell, Trion Air Bear, Bryant, Carrier, Trane Filters and IAQ products

All the info you should need is under the Files tab in the link.

Celsius is a changeble parameter. The stat will be intimidating. No question about it.

[KISS]

The 1016 is a private label version: http://customer.honeywell.com/TechLi...s/50-9237C.pdf

And if you want the lit from Honeywell's site, look here:

Default - Honeywell Environmental And Combustion Controls

[KISS]

Remember, you will need to install the optional outdoor air sensor!!

[KISS]

PS:

It requires a different mentality to search Honeywell's site. I figured it out, but not without lots of frustration. It's easy once you know how.

[LouisB]

What's so hard:

TH8320U1008: $139.95 | Honeywell VisionPro 8000 Programmable MultiStage Thermostat | iaqsource.com - Aprilaire, Honeywell, Trion Air Bear, Bryant, Carrier, Trane Filters and IAQ products

All the info you should need is under the Files tab in the link.

Celcius is a changeble parameter. The stat will be intimidating. No question about it.

Thanks, just saw the light!. Files in the link.

[LouisB]

The 1016 is a private label version: http://customer.honeywell.com/TechLi...s/50-9237C.pdf

and if you want the lit from Honeywell's site, look here:

Default - Honeywell Environmental And Combustion Controls

Now that was easy... Thank you.

[LouisB]

Remember, you will need to install the optional outdoor air sensor!!

Will this be to provide some baseline signal to which the setup can be made to turn off the feed to the "Y" connection? This connection already gets blocked at -12C.

[LouisB]

PS:

It requires a different mentality to search Honeywell's site. I figured it out, but not without lots of frustration. It's easy once you know how.

Ha.. you have power!

[KISS]

Heat pumps don't operate very well below some temperature. That minus 12 C doesn't look quite right. 4 C makes more sense. 12 C seems a bit high. Heat Pumps

So, something has to make the switch with dual fuel. The heat pump controller or the thermostat are the only two choices.

The best way that the system can make that decision is on the outside temperature near the intake of the outside unit.

The simplest way is to say below a certain outside temperature, lockout the heat pump and above that temperature with some hysteresis added in use the heat pump. If the HP is off, then, and only then do you bring on the fossil fuel.

A better way is to do the above, but add another condition. That condition is the system can't seem to get to the desired setpoint with the heat pump, turn the heat pump off and switch to fossil fuel.

Anyway you look at it something has to know the outside temperature to make that decision. Either the furnace can be smart or the thermostat could be smart, but they both need an outdoor sensor.

Carrier, in their Infinity models, may put the sensor in the heat pump/AC or it can be located elsewhere and connected at the furnace.

What you did notice is that when the system gets complicated, there are way too many wires to be connected at the stat and the Vision Pro requires the temperature sensor to be connected at the stat.

One model of the vision Pro line uses an "Interface module" http://www.ntsupply.com/files/products/EIMINSTALL.pdf
That mounts at the furnace. It only requires 3 wires to the stat. With dual fuel, you'd need an extra two for the outdoor sensor. So that's a total of 5 at the stat.

[LouisB]

Heat pumps don't operate very well below some temperature. That minus 12 C doesn't look quite right. 4 C makes more sense. 12 C seems a bit high. Heat Pumps

So, something has to make the switch with dual fuel. The heat pump controller or the thermostat are the only two choices.

The best way that the system can make that decision is on the outside temperature near the intake of the outside unit.

The simplest way is to say below a certain outside temperature, lockout the heat pump and above that temperature with some hysteresis added in use the heat pump. If the HP is off, then, and only then do you bring on the fossil fuel.

A better way is to do the above, but add another condition. That condition is the system can't seem to get to the desired setpoint with the heat pump, turn the heat pump off and switch to fossil fuel.

Anyway you look at it something has to know the outside temperature to make that decision. Either the furnace can be smart or the thermostat could be smart, but they both need an outdoor sensor.

Carrier, in their Infinity models, may put the sensor in the heat pump/AC or it can be located elsewhere and connected at the furnace.

What you did notice is that when the system gets complicated, there are way too many wires to be connected at the stat and the Vision Pro requires the temperature sensor to be connected at the stat.

One model of the vision Pro line uses an "Interface module" http://www.ntsupply.com/files/products/EIMINSTALL.pdf
that mounts at the furnace. It only requires 3 wires to the stat. With dual fuel, you'd need an extra two for the outdoor sensor. So that's a total of 5 at the stat.

Great info on the referenced link.

The VisionPRO 8000 thermostat can perform a timed ramping function to reach selected temperature before fuel heat is activated. Once this happens, this is where I need assurance that the HP ("Y" feed wire) becomes at 0 volts... and I will be checking this with a voltmeter... so there... I will then have my answer!

We benefit from the electric utility's dual-energy low rate program; at minus 12C and below, the power rate almost triples, reason why the HP locks out at minus 12C... so it remains cheaper to maintain the HP active as long as possible. At some point, probably at around the minus 4C you suggest, the HP benefits become questionable, but still when the Utility power being metered above minus 12C remains in, the HP can remain active and surf the fuel heat supply with the make-up BTUs needed to maintain set point temperature. Question of balancing a ramp-up time versus efficiency.

If it was not for the dual energy power rate, I would see the need to use an outside temperature sensor to limit HP activity before cost efficiency becomes negative.

I will be reporting final outcome sometime next week... meanwhile please accept my gratitude for your generous contribution in time and info.

[LouisB]

Great info on the referenced link.

The VisionPRO 8000 thermostat can perform a timed ramping function to reach selected temperature before fuel heat is activated. Once this happens, this is where I need assurance that the HP ("Y" feed wire) becomes at 0 volts...and I will be checking this with a voltmeter...so there...I will then have my answer!

We benefit from the electric utility's dual-energy low rate program; at minus 12C and below, the power rate almost triples, reason why the HP locks out at minus 12C....so it remains cheaper to maintain the HP active as long as possible. At some point, probably at around the minus 4C you suggest, the HP benefits become questionable, but still when the Utility power being metered above minus 12C remains in, the HP can remain active and surf the fuel heat supply with the make-up BTUs needed to maintain set point temperature. Question of balancing a ramp-up time versus efficiency.

If it was not for the dual energy power rate, I would see the need to use an outside temperature sensor to limit HP activity before cost efficiency becomes negative.

I will be reporting final outcome sometime next week...meanwhile please accept my gratitude for your generous contribution in time and info.

Today took my voltmeter to task and saw confirmation that the Honeywell VisionPRO 8000 thermostat maintains 24 Volts on the Compressor "Y" feed wire when same thermostat calls for emergency heat if the setting is not attained by the heat pump in the required ramp-up time. Therefore I conclude that without adequate protective control circuitry downstream of the thermostat, the compressor is at risk of failure by excessive head pressure developing in the evaporator/compressor combo. I also conclude that any of the Honeywell thermostats currently available are not properly engineered for stand alone control over combined Heat Pump/Emergency Heat use.
Consider this: In the Heat Pump mode, the hot gas reaches the evaporator, which in a Fuel Furnace, will be located in the air plenum sitting above the fuel burner. Normally the gas gives up heat and returns to the compressor in a gaseous-liquified state, meaning cooled down. With current total dependency on the thermostat to control heat sources, when it initiates the emergency heat, the heat pump keeps working and it's gas will not give up it's heat and au contraire will pick up heat in it's passage through the evaporator thus being super heated by the fuel burner. This process brings superheated gas back to the compressor, not a good situation leading to a shortened compressor/evaporator life expectancy, if not sudden failure or loss of gas.

To circumvent, I will pass the compressor relay feed wire (Y) via a relay's NC contacts which open, cutting off the compressor relay, when the fuel heat relay's feed wire gets activated by the thermostat (W). Hopefully this will correct the Contractor's oversight. The fuel relay happens to have the required set of NC contacts. Note that the Totaline thermostat avoided the heat source conflict, but could not do better than 1 to 1.5C deadband on temperature setting. The Honeywell thermostats do +/- 0.5C.. at least do that adequately.

Do you agree/disagree or have suggestions?
Thank you...

[KISS]

I don't know which model stat that you have, but I think you may still have the wrong one.
Only the one with the interface mounted at the furnace will work in your case. (Model YTH9421C1002).

Here are some of the more important parameters:

0172 2 = Heat pump
0176 (Heat/aux stages) 2
0200 1 = fossil fuel backup heat
0210 0 = thermostat controls backup heat (outdoor sensor required)
0342 1 = outdoor temp sensor exists
0345 (Dual fuel heat pump control) 2 = Balance point/Aux heat lockout plus 2 deg F droop
0350 -12C Heat pump compressor lockout
0360 -12C Heat pump Aux lockout

I believe that those options willl do what you want to accomplish. It does require an outdoor sensor.

I do think you have the right idea, but it's not optimal. It just will prevent the fossil fuel system from being on when the heat pump is on. It's not a bad safety to have anyway, even in my suggested scenero.

So, what are your comments?

[LouisB]

I don't know which model stat that you have, but I think you may still have the wrong one.
Only the one with the interface mounted at the furnace will work in your case. (Model YTH9421C1002).

Here are some of the more important parameters:

0172 2 = Heat pump
0176 (Heat/aux stages) 2
0200 1 = fossil fuel backup heat
0210 0 = thermostat controls backup heat (outdoor sensor required)
0342 1 = outdoor temp sensor exists
0345 (Dual fuel heat pump control) 2 = Balance point/Aux heat lockout plus 2 deg F droop
0350 -12C Heat pump compressor lockout
0360 -12C Heat pump Aux lockout

I believe that those options willl do what you want to accomplish. It does require an outdoor sensor.

I do think you have the right idea, but it's not optimal. It just will prevent the fossil fuel system from being on when the heat pump is on. It's not a bad safety to have anyway, even in my suggested scenero.

So, what are your comments?

Contractor installed the VisonPRO 8000 Model TH8320U(1016) wothout an external FF kit.
So I will be making up my own FF Kit as follows:
- Minus 12C probe already installed with relay to lockout HP; this relay diverts "Y" feeder's 24 V to the Fossil Fuel relay.
- Same FF relay will also have a NC contact via which I will pass the "Y" wire coming from the above lockout relay. The HP relay will thus be de-energized whenever the thermostat's "W" FF Heat relay feeder wire is live.
Voilà, problem resolved.
As mentionned earlier, we benefit by working the HP as close as possible to the minus 12C lockout, and using it to supply make-up BTUs if FF Heat becomes principal source.