Problems related to residential installations.
One thing at a time. First install the filter grilles we KNOW you need. Then if there's still a problem we can look at the supply side. The open blower door already tells you the filter grilles are necessary now.
Hi freon, still deciding whether to order the grilles and filters, a bit of a pain ordering them from Canada, a few unknowns it will be about $300. Also I have come up with a simple circuit for the HRV to interlock with the furnace at the low speed. The probelm is the blower motor can only have one speed lead energized at any one time. My circuit using 2 - 24vac relays, upon the W and G wires being energised by the thermostat, R is the power lead, that would energise the specific relay and open contacts of the 115vac to the RED low blower speed through the contacts of the HRV. The 115vac travels though NO contacts of the HRV would control the on and off of the low speed selection. This enables me to use HIGH speed for the HEAT, MED-HI for the COOL, and LOW speed for the HRV for recirculation. The trick is not have have the blower motor see more than one lead energised with the 115vac, the manufacture indiates that this would be detrimental to the motor. I should map it out on paper so you can see it. Jim