Install#1 after upgrade: Close-up 3-flex and plenum heater and 3-Flex controller.
Install#1 before upgrade: close-up dual-heat fossil fuel kit.
dual-heat to tri-heat coversion pictures.
Install#2 before upgrade: Oil furnace + heat-pump dual– heat and old oil fired hot water boiler.
Install#3 before upgrade: Oil furnace + heat-pump dual– heat.
Install #3 after upgrade: 3-Flex tri–heat installed.
3-Flex tri–heat installed 1 hot air intake pipes needed re-routing. 3-flex and plenum heater without cover.
Hoyme motorized fresh air intake damper.
By building safety code, combustion furnaces require a separate fresh air intake. To prevent unwanted cold air infiltration a motorized fresh air damper controlled by 3-flex allows outside air into the house only when the furnace is on.
Front/top view of a typical custom built multi-stage electric plenum heater controlled by 3-flex for installation in the vertical stack on top of the indoor heat pump coil as shown in install #1 pictures.