Interlocking the lifebreath HRV to air handler

[Stmargaretsbay]

Hi, I am wanting to interlock a newly installed HRV (Lifebreath 155 max) to a Goodman air handler (3Ton Heat pump). The wiring diagram from the manual seems straight forward however I am not clear whether

1) I install the main controller (99-DXPL02) and also interlocking wiring ?
2) do I install just the main controller or just the interlocking wiring (ie one or the other) ?
3) should I be concerned about taking the fan control wire G off the air handler  terminal and sending it through the HRV block?

I am looking at this as running the three wire for the main controller to the mainlevel and then another three wire to the furnace air handler.

*Also: will this interlocking control the fan speed of the hrv to match the air handler? The air handler runs continuously on low (500cfm) and at 1000cfm when heating or cooling and at 1500 cfm with Aux. heating. Presumably it would speed up and slow down accordingly in parallel with each other under this wiring control?

I should also note that this is tied into a Nest thermostat........which always seems full of surprises.

Many thanks for your help and the best to all in this New Year

[Admin]

The NEST can't control the HRV so nothing to worry about there.

Wire the main control then use another 3 wire to interlock the HRV as shown in your 2nd pic.  Yes, you will be removing the G wire from the air handler G terminal and anytime the HRV starts it will run the continuous fan speed in the air handler.

[Stmargaretsbay]

Thank you for the reply and understood. Green is fan on off and not speed control. That would be controlled with the air handler circuit board and dip switch's, I believe .

Can I assume the HRV adjusts its speed with the air handler in-order to maintain balance?

Depending on what is calling from the thermostat the fan speed is low (continuous), med (regular heating) or high (Aux heating 10 kW strip).

Will the HRV adjust accordingly to maintain balance with this set up?

Thank you!

SMB

[Stmargaretsbay]

EDIT - the above should not have been "maintain balance", really, but will it adjust fan speed with air handler? Thanks.

[Admin]

The fan on feature usually runs a low speed in the air handler or furnace and then heating or cooling would change the air handler fan speed.

Anytime the HRV runs, without heating or cooling, the air handler would always be the same speed that you get by turning the thermostat fan from auto to on. If the HRV is turned on while the furnace is heating or cooling the air handler fan would run with the HRV at that speed. 

HRV balancing refers to the motors inside the HRV which have been balanced to ensure the same amount of air leaving the home is being bought back into the home.

And the HRV balancing is usually done with only the air handler continuous fan speed running.