[mrrich]

Ok let me see if I can explain this.
I have a Goodman Variable Speed Gas Furnace / Electric R410a Hybrid Heat System.DSZ160361A / GMVC950905DX / CAPF3743D6 Split System.With a White Rodgers Thremostat 1f95-1277 and Aprilaire 5000
Electronic Air Cleaner.
Unit is installed with AFE18-60 Electronic All Fuel Control Board and a
OT18-60 Outdoor Heat Pump Stat set to 0 degrees.
Indoor thermostat is programed for Heat Pump Type 2

Functions normal in cooling.When in heat mode, furnace calls for Gas heat and not Heat pump "1st Stage".

Is this something I'm missing in programing the indoor thermostat or some kind of dip switch on the furnace-air handler?
Please note that Gas supply is not hooked up yet.Could this be a problem with the Heat Pump not working in 1st Stage?
Furnace will try to ignite when heat is activated.I assume that Gas is 2nd Stage?
Would like to use the 1st Stage Heat (Heat pump only) with out Gas ignitor fireing and normal cooling.
Gas line will be installed at a later date.

[KISS]

Here is the manual for the AF control: http://www.totalairsupply.com/files/...anual_9-06.pdf

Note, you may wish to use/install the outdoor thermostat.

What I think may be happening is that there is a lerge difference between setpoint and measured temperature. Large can be > 1.6 deg. Because of this, the thermostat will engage 2nd stage heat immediately. Because of the dual-fuel board the HP is not allowed to run. The instructions may not be obvious.

Instead of the dual fuel board, you could have used a Honeywell Vision Pro thermostat that supports dual fuel, but I requires an outdoor temp sensor.

You need o find out from the installer the balance point or the outdoor temperature where the output of the HP equals the house loss. You also need from the mfr, the temperature in which the HP doesn't work well at all. That's probably the 0 Centegrade. That's when the gas furnace is used alone.

You really want the gas furnace to take over when the HP output is equal to the house loss. When there is electricity and gas costs involved then that point can be better managed by knowing efficiency vs outdoor temp of HP and cost/therm of electricity.

Some of our Canada counterparts really don't want to run the gas AT ALL unless they have to because hyro power (dams) is really cheap. It would then be nice to have that flexibility in the stat to change the outdoor temp when the switch occurs.

[Missouri Bound]

Did it stop working? Did you change the thermostat? Did it work at some point? What led up to this problem?

[KISS]

Moving call for first stage heat to 2nd stage heating and disconnecting call for 2nd stage heating should solve it for now.

Dual fuel adds a lot of complications and there may not be anything wrong with how it's hooked up. The large temp differential probably causes the 2nd stage to come on.

Move the setpoint to within 0.5 deg of each other and turn it on. See if you don't get the heat pump.

[mrrich]

Did it stop working? Did you change the thermostat? Did it work at some point? What led up to this problem?

System is new,works in cooling.1st time I have installed a HVAC,had a pro charge and sweat lineset.Asked him about wireing and he said it was OK.I think its just the temp difference on the set point.I have not had a chance to test yet.

[mrrich]

Here is the manual for the AF control: http://www.totalairsupply.com/files/...anual_9-06.pdf

Note, you may wish to use/install the outdoor thermostat.

What I think may be happening is that there is a lerge difference between setpoint and measured temperature. Large can be > 1.6 deg. Because of this, the thermostat will engage 2nd stage heat immediately. Because of the dual-fuel board the HP is not allowed to run. The instructions may not be obvious.

Instead of the dual fuel board, you could have used a Honeywell Vision Pro thermostat that supports dual fuel, but i requires an outdoor temp sensor.

You need o find out from the installer the balance point or the outdoor temperature where the output of the HP equals the house loss. You also need from the mfr, the temperature in which the HP doesn't work well at all. That's probably the 0 Centegrade. That's when the gas furnace is used alone.

You really want the gas furnace to take over when the HP output is equal to the house loss. When there is electricity and gas costs involved then that point can be better managed by knowing efficiency vs outdoor temp of HP and cost/therm of electricity.

Some of our Canada counterparts really don't want to run the gas AT ALL unless they have to because hyro power (dams) is really cheap. It would then be nice to have that flexibility in the stat to change the outdoor temp when the switch occurs.

Thanks for the advise
One more question if I may.
How do I determine the "Balance point where the output of the HP equals the house loss"? Is there a formula or something?
Here in Tennessee gas is more expensive than electricity to use.
The Pro that I had Sweat the Line Set and Charge the system recommended the outdoor stat to be set between 30-40 degrees.

[KISS]

So, you'll get the idea: How cold is too cold for my heat pump?? - Heating & Air Conditioning Forum - GardenWeb

I'll give you a couple of websites to munch on: COP diagrams for some heat pumps

Balance Point Calculations
Heat Pumps

On your original question, the calculation is called "Manual J".
One such program is here: HVAC Software, HVAC-Calc for Heat Loss, Heat Load Calculations

You can, determine the temperature where heating with a HP equals the cost of heating with gas. Yep, you need to know Therms/cubic feet which is on your gas bill. This constant is somewhat gas composition specific.

[Missouri Bound]

Heat pumps should always run on the first stage, with the second stage coming on IF the first stage can't keep up, or when the heat pump is defrosting. If your heat pump produces warmer air than the room it's trying to heat, then it's working. Finding the balance point when it becomes more economical to run on fossil fuel should be determined by professionals. New heat pumps are very close in efficiency to gas heat.

[mrrich]

Thanks for the help