This was a first for me so I need to know if this is standard practice. The kitchen, laundry, bath and master bath bath exhaust fans were actually a timer device which operated the blower which pulls air thru the HRV. Owner stated that a humidity sensor reads the air and if it contains high moisture content, exhausts the moist air out of the home. Otherwise it cycles it thru the return ducts.
Does any of this sound right? I have very limited experience with HRV, but I cannot see cycling momma’s burnt dinner smoke thru the return register into the HRV and back into the home?
If all of the returns go to HRV and out of the house and not the furnace return should be acceptable. Returns from bathrooms or kitchens going to furnace or air handler returns is not.
I am not totally understanding what you are describing here, but I would state bathrooms and kitchens can not be connected to the return system in any form.
Just looked through HVI 929 Installation Manual for Heat Recovery Ventilators. Removing air from the bathrooms and kitchen is just one ducting arrangement. However those returns are connected directly to the HRV which then expels that air outside through the HRV exhaust. The ducting arrangements illustrated do show that outside air can be ducted individually to room locations or centrally to a furnace or air handler return. Fresh outside air from the HRV is the only ducting arrangement to a return is the only configuration shown. Though not shown in the HVI manual individual HRV manufacturers do allow air connection of their HRV to a central return for outgoing and incoming air.
If the bathrooms and kitchen returns do connect to a central furnace or air handler return this is not allowed. If they connect only to the HRV then this arrangement would be allowed as this air would be expelled outdoors.