hussmann P/N 0387183_D - Manual (Page 16)

CONTROL SETTINGS
MEDIUM TEMPERATURE
Conventional Single Compressor
Measure Discharge Air Temperature
at the center of the case
at the discharge honeycomb.
Merchandiser temperature must be controlled by
a thermostat or other device with a 3–6 deg F
(1.7–3.3 deg C) differential. It will be wired to
control the compressor motor contactor.
Standard Off Time defrost is temperature termi-
nated. The defrost termination thermostats for all
the merchandisers on one compressor are wired
in series. On outdoor units the defrost timer will
control a liquid line solenoid beginning a defrost
pumpdown 4 minutes before defrost.
The defrost frequency and lengths listed may
require adjustment for specific store conditions.
Factors include:
Store temperature and humidity
Low head pressure
Long refrigerant line runs
Seasonal changes
Merchandiser temperature lower than
recommended
When practical, defrost when store is closed.
Low pressure control settings are applicable to
outdoor condensing units where ambient does not
fall below 0 deg F.
CONTROL SETTINGS
LOW TEMPERATURE
Conventional Single Compressor
Measure Discharge Air Temperature
at the center of the case
at the discharge honeycomb.
Merchandiser temperature must be controlled by
a thermostat or other device with a 3–6 deg F
(1.7–3.3 deg C) differential. It will be wired to
control the compressor motor contactor.
Standard Electric defrost is temperature terminat-
ed. The defrost termination thermostats for all
the merchandisers on one compressor are wired
in series. Failsafe must not control defrost cycle
length, especially when less than 208V power
supply is used for defrost heaters, or if frost
build up is heavy from shopping demands.
On outdoor units the defrost timer will control a
liquid line solenoid beginning a defrost pump-
down 4 minutes before defrost.
Optional Gas defrost is time terminated and has
fan cycling thermostat. The defrost frequency and
lengths listed may require adjustment for specific
store conditions. Factors include:
Store temperature and humidity
Low head pressure
Long refrigerant line runs
Seasonal changes
Merchandiser temperature lower than
recommended
When practical, defrost when store is closed.
Low pressure control settings are applicable to
outdoor condensing units where ambient does not
fall below 0 deg F.
2-6 R
EFRIGERATION
/ E
LECTRICAL
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