Therma-Stor Products Group UA-150H - Manual (Page 19)

If the electric ventilation damper fails to operate:
1. Check that the wiring is correct and that voltage is present at
the damper motor.
2. Check for any obstruction inside the damper. If the electric
ventilation damper fails to operate after performing these
checks, it must be replaced.
7.10 Low Pressure Control
If the low side refrigerant pressure drops to 15 PSIG, the low-
pressure control opens and shuts off the compressor and impeller
fan. It is an automatically reset control. It will close when the
refrigerant pressure rises to 35 PSIG. Its primary function is to
prevent damage to the compressor if a leak develops in the
refrigeration system. It may also open if the unit is A) installed in a
cool area (below 50 F) or B) installed where it is below 40 F and then
started. Under these conditions, the unit will restart within several
minutes. Until the unit warms up, it may cycle several times.
7.11 Condensate Pump Kit
An optional condensate pump kit is available from the factory for use
with the UA-150H. Condensate is automatically pumped to a remote
location when the water level in the pump's reservoir rises to close
the float switch.
The pump also contains a safety float switch. The white leads from
this switch extend from beneath the pump cover. This switch should
be installed in series with the field wire that connects the blue (#5)
lead from the UA150H to the blue (#5) lead on the control panel.
If the pump fails, this switch opens the compressor control circuit
and stops water production before the reservoir overflows. The UA-
150H will continue to ventilate or circulate air as normal, but will not
dehumidify until this switch closes.
FOR HVAC INSTALLER ONLY
19 Ultra-Aire 150H Installer’s & Owner’s Manual
Electric Schematics of the UA-150H