I have recently installed two 20 SEER
American Standard communicating AC split systems with hydronic coils
for heat. The hydronic coils are controlled by a board or HHC
(BAYWVBRD485A) that is supposed to integrate seamlessly into the
communicating system. The AC works fine with both systems. When I
turn up the heat on the tstat it shows the set point but "heat
on" never shows up, thusly no call for heat. shortly following
this I get an error 89 code which indicates "equipment missing"
or "expected equipment is not reporting." I have spoken to
American Standard tech support. They confirm that all my wiring and
programming is correct. Next on the list to check is the DC voltage
coming to the HHC.

I am just wondering if I am alone with this