Omnistat2 dual-fuel settings

[PDR983]

I have an Omnistat2 RC-2000 thermostat controlling a HVAC system composed of a Carrier single-stage heat pump, dual-stage forced air furnace on a house with an Omni IIe control system. Temperature is programmed to 62F night/70F day. When outside temperature is below the lower balance setpoint (30 F), the auxiliary heat does not come on in the morning consistently and raise the temperature to the daytime setpoint, even though the setpoint on the thermostat shows the correct setpoint of 70F. However, the auxiliary heat comes on when I manually increase the setpoint to 73F, which seems to indicate the system is connected correctly and that the problem is with the thermostat settings. Likewise, temperature is maintained at the lower setpoint even when outside temps are cold, showing that it's able to maintain temperature with auxiliary heat. There are no problems when outside temperature is above the lower balance setpoint.

I've tried changing the EEC and anticipator controls, but haven't been able to resolve the problem. Any suggestions or troubleshooting advice would be appreciated. I've included the current settings below.

Thanks,
Tim

No internal programming
Cool min on - 7
Cool min off - 8
Heat min on - 7
Heat min off - 8

Cool stages - 1
Heat stages - 3

Heat eec - 4
Cool eec - 5
2nd stage differential - 1
start delay - 5 min
aux heat differential - 2
start delay - 15 min

Cool anticipator - 5
heat anticipator - 4
2nd/3rd stage extended on - on

balance setpoint - upper=70F, lower=30F

 

[rsw686]

Make sure the system type is set to dual fuel and not heat pump. On page 9 there is a section for "About Dual Fuel Heat Pump Systems" and what will operate depending on the outside temp in relation to the setpoints. Looking through the examples it looks like dual fuel might only be supported with 2 stages of heat.

 

[HomeTechNewbie]

I am also interested in this. I have 4 zones that seem to be cross wiring each other...

 

[PDR983]

Thanks. The system is set to dual fuel, but with three stages for heating. I'll have to check, but the second stage of heating may be something the furnace does automatically depending on how long it runs and isn't under control of the thermostat, which would mean two stages of heating (heat pump and furnace). Still, the furnace comes on when I bump the temperature up in the morning and the furnace comes on when needed while heating during the day. The issue is why it doesn't switch on when the programmed temperature changes in the morning.

 

[ebm]

I'm having the same problem with my dual fuel heat pumps (set to 2 stages).  The temperature change in the morning does not cause the system to turn on the heat.  I have to manually adjust it (up or down by any amount) to get the heat to start.  Very annoying. 
 
Confirmed with HAI tech support the settings are correct and the wiring is correct.  Also have the latest firmware. They suggested setting EEC to zero, but that didn't make a difference.   I suspect this is a bug in the RC-2000 firmware.  Can't believe this is unique to the dual fuel heat pumps and that more people are not complaining about it. 
 
Configuration of Tstats 1 and (2) (both connected to Omni Pro II):
Tstat address 1 (2)
Communication Mode: serial
    system baud 100
    expansion baud 1200
System Options
    Dual fuel heat pump
    mode: auto changeover
    Fans with heat stages: 1 & 2
Program Mode: Schedule
Calibration offset
    0.0F
    0.0% RH (not available on Tstat 2)
Cool/Heat Limit
    Cool setpoint min: 48
    Heat setpoint max: 88
Min on/off time
    Cooling min on: 7
                    off: 2 (5)
    Heat min on: 7
                  off: 2 (5)
Stages settings
    Cool: 1 stage
    Heat: 2 stages
EEC Control
    Cool EEC: 5
    Heat EEC: 5
Aux Heat diff: 2F
Start delay 0:05
anticipator control
    Cool anticipator: 5
    Heat anticipator: 2
    2nd/3rd stage extended on: on
Temp Sensors
    internal sensor: enabled
    external sensor 1: outdoor
Humidity Option
    Dehumidify: Not Used (should be D when used)
    Humidified: Not used
Emergency Heat Options: none
Balance setpoints
    Upper setpoint: 48
    Lower Setpoint: 38 (42)
Fan Cycle Time
    Fan on: 4 (5)
    Fan off: 16 (15)
Setpoint Options
   Confirm setpoint changes: off
Energy Savings
    Setback: 4F
 
I have a third RC-2000 heat pump with aux heat.  That doesn't seem to have this same issue consistently.