The controls are all used items taken from the scrap/ save for a rainy day pile.
A cabinet was gutted to put the control relays in and stats were mounted beside cabinet.
The outdoor stat will shut down the air conditioner and start the air exchanger if the outdoor temp is below the 35 deg F storage set point. and a cooling demand is initiated.
One problem encountered is the freeze-up of coils on air conditioner, this required an additional stat to sense the air temp leaving the conditioner and shut down the compressor. With compressor off and fan still turning, the frost is removed and sent into the space to preserve the moisture level.
The timer shown in center of control box is a trial unit and was meant to energize the fan for ten minutes every hour to remove air stratification, it does not seem to be programmable for this and will be replaced later.
