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Hybrid settings for Honeywell T6 Pro Smart for heat pump & Peerless.

Rob94hawk
Rob94hawk Member Posts: 12
edited October 21 in Thermostats and Controls

Just had an install of a Bosch M20G 5 Ton AC/Heat pump and still kept my Peerless boiler/baseboard heating. I've been told for the heat on the Bosch to set it and forget it. But I'm trying to figure out when to have the oil burner kick in to assist the Bosch on very cold days in NY.

I turned the heat on only once when it was cold in the a.m. and if I recall, the baseboard AND the heat pump kicked in. I have the WiFi off. See no need for it.

The T6 came with the system and has a lot of ISU settings. Definitely a big learning curve. Could use advise. Thanks.

Comments

  • HVACNUT
    HVACNUT Member Posts: 6,100

    That should have been set up with the installer.

    There might only be a 1 or 2 degree differential before the boiler comes on. If you set the thermostat one degree above setpoint, only the Bosch should run.

    The boiler should also run during defrost if there's a heat demand at the same time.

  • SuperTech
    SuperTech Member Posts: 2,288
    edited October 21

    Why run the boiler during defrost? It's not going to prevent cold air from blowing from the heat pump and I would think that the burner wouldn't run long enough to heat up the chimney enough to prevent condensing. I usually leave W from the outdoor unit disconnected on systems like this. I try to set up the system so the heat pump never goes into defrost if possible. Let the boiler take over if the temperature is below freezing.

    EdTheHeaterMan
  • HVACNUT
    HVACNUT Member Posts: 6,100
    https://forum.heatinghelp.com/discussion/comment/1815468#Comment_1815468

    Ok. IDK how you prevent the defrost cycle unless it's not that cold. The newer systems have it built into the board on a timer and/or coil sensor. If you're lucky you can set the frequency.

  • SuperTech
    SuperTech Member Posts: 2,288

    I usually set them up for switching over to the boiler or furnace at 35⁰, this minimizes the possibility the heat pump needing to defrost when the time and temperature defrost boards are set to 60 minutes.

    With furnaces I worry about the coil being hit with high temperature air from the furnace during a defrost cycle. Maybe I am overthinking things, but I haven't had any complaints from customers with these setups.

    Certainly with a Bosch inverter heat pump you can run it to much colder outdoor temperature without losing any efficiency compared to a single stage heat pump. I might set them up differently.

  • Kaos
    Kaos Member Posts: 53
    edited 1:55AM

    What are your local utility rates? Also what is the model number of your outdoor unit? In my area anything oil is 3x heat pump cost so you never want to run it, gas is about even bellow 10F. About the only reason to switch over is if the heat pump runs out of steam or the air temp starts to drop on non EVI units.

    Defrost cycles are simple to deal with. Simply turn off the circulation fan, most allow you to configure this. Works very well the only way you know that a defrost cycle is happening is that the house goes quiet for a minute or two. After the defrost most have a delay to allow the indoor coil to re-heat so it never blows cold.

    The one you don't want is to use aux heat strip during defrost. This uses a lot of electricity for no reason.

  • Rob94hawk
    Rob94hawk Member Posts: 12
    https://forum.heatinghelp.com/discussion/comment/1815590#Comment_1815590

    Outdoor model: BOVB-60HDN1-M20G
    Indoor model: BVA-48WN1-M20

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