Zone Sizing & Clamp LV settings (Trane)

[MooseMan]

Entering our first winter in the northeast with a multizone dual fuel heating system. System is a Trane: XC95M Furnace, XV20i Heat Pump, and XL1050 Control. The heat pump has been fantastic, but now that its colder I'm curious about efficiency, cutover, and NOISE. Right now it is 20 degrees out, and it sounds like an airplane - so that has me trolling through configuration options, and reviewing the installer's original config (with the setup manual, of course). I have 3 questions:

1) "Clamp LV for Aux Heat" Setting. p. 9 "Select whether to clamp the system load value based on the sum of the calling zones sizes to limit auxillary heat operation. >> Can someone translate this to English? Aux Heat is the propane system. Right now this is disabled.
2) "Zone Airflow Capacity" Setting. p. 9 - % of airflow each zone can handle - auto vs manual. Installer had it manually set at Z1; 85%, Z2; 70%. When I ran the Auto protocol it came up with Z1 97% and Z2 105%., which wouldn't apply because the max for any 1 zone is 100%. For reference Z1 is upstairs, larger, open floorplan. Z2 is downstairs, smaller, with many rooms.
3) "Dual Fuel Calculator" p. 15 - this is becoming its own thread.

 

[Fitter30]

Believe lv load value. The installing contractor went to school for this system so they could sell it. Start changing programming and when u start having fault codes pop up don't be surprised. Zone damper setting could throw the balance of the system off. Call them back out.

 

[Sponsor]

 

[WorthFlorida]

1) "Clamp LV for Aux Heat" Setting. p. 9 "Select whether to clamp the system load value based on the sum of the calling zones sizes to limit auxillary heat operation. >> Can someone translate this to English? Aux Heat is the propane system. Right now this is disabled.

Load value for AUX heat. Clamp means limited use of the AUX heater. When you're that cold HP alone probably cannot handle the entire heat load. This smart system can calculate how much heat is needed and I would not restrict any AUX heat setting. Usually the AUX heat will turn on based on several factors. One is the set temperature and actual thermostat room temperature. If more than two degrees the thermostat turns on the AUX heat. Another determination is it learns how long it takes to bring the room to the set temperature and if it takes too ling the AUX heat can turn on. Another is a weather station via WiFi gets a reading of the outside temperature if the unit does not have its own outdoor sensor. Most simpler systems the thermostat does all the work. I didn't look it up but your system may have a proprietary thermostat where most of the smarts is on a board in the air handler system.

Not long ago there was another post with the same issue, the colder it became the fan in the compressor unit really cranks up to get more air over the coils for more heat absorption. As Fritter30 suggest, if this is a new system installed after you took ownership, under one year the installation company should come out to balance the system or at least call them with questions.

 

[Fitter30]

Did the contractor run a load on the house? Measure each room? How many times have they been out? Over 3 u want factory service rep. Tell them u will have coffee on donuts or danish? Spent what 20k +.