Cold weather now. Downstair not that warm air (air flow rate normal) 60 degree , upstairs (different zone) ok. Each zone has its thermostat. Changed battery at thermostat. Azrel 202 MPS2 system with pneumatic damper control ( I just learned today this control pressure tube could go 100 ft).
I looked up old record. This little air pump was replaced 8 years ago. It is the bottom white part in the large photo below.
My questions:
Are there 2 wires going to the solenoid for each of 2 zones? It looks like single damper for both upstairs and downstairs (2 zones).
Other than pumps, what other issues should I look for?
