My system installed in 2006: 3 ton Envision NDV038A111NTL 10 kW heater desuperheater tp32u03 Thermostat 3500sqft including finished basement We previously had a TA32W0L thermostat & recently changed to a TP32U03 thermostat a few days ago. The TP32U03 is set for multi-stage & duel fuel. All wiring copied from old thermostat. Last week when temps dropped here to -13F, the temperature from our registers when stage 3 kicked in was 110F, stage 2 was 85F & stage 1 was 82F . The furnace kept the house at 70F fine but used stage 3 a lot. This new thermostat set for multistage/dual fuel struggles to keep the house at 70F using stage 3 with an outdoor temp of 12F. Testing the new thermostat by forcing stage 3 to kick in by raising the temp 5 degrees & also tried running in emergency heat only, the register temp will not go above 95F at any time. We disabled the 10 kW heater & stage 2 is 88F. Stage 1 is 84F. There is no way the furnace will heat our house without the 110F register temp if we have outside temps like last week. What happened to the 110F register temp that we had with the old thermostat. Is there a setting in the thermostat that we are missing? Thanks for any help.
The Dual Fuel setting is for systems that have the aux heat source mounted BEFORE the HP air coil. Most commonly a gas furnace with the HP aircoil mounted on the outlet (as recommended by gas furnace manufacturers to prevent condensation in the gas furnace during AC operation). In a Dual Fuel configuration the HP can not operate normally with already heated entering air from the aux heat source. The Dual Fuel setting will turn the HP off during any Aux heat call and will will not allow downstaging to HP operation because of this. A typical geo packaged unit has the electric aux heat mounted AFTER the HP aircoil. Both can run simultaneously if needed. I believe you DO NOT have a Dual Fuel system and you should change the Down Staging setting to Normal.
Sorry it is multi fuel not dual fuel. The options are multi fuel - electric - no auxiliary heat. So I should choose electric? Thanks.
