P/N 3104942_B
3-7
HUSSMANN CORPORATION • BRIDGETON, MO 63044-2483 U.S.A.
SHM-A Merchandisers
The controller controls refrigeration temperature.
This is factory installed in the control panel. Adjust
the control to maintain the discharge air temperature
shown.
The factory defined setpoint is required to comply with
energy regulations such as from the Department of
Energy (DOE). If for some reason, colder temper-
tures are required for customer specific products the
setpoint can be adjusted.
Discharge air temperatures should be measured at
the center of the discharge honeycomb.
Defrosts are time initiated and temperature
terminated. The defrost setting is factory set as
shown above.
To ensure a thorough defrost, defrost must be
terminated by the temperature termination
setting — not by time.
The Chart shown in the figure above describes
the operation of a SHM4A model under ambient
conditions such as 75°F and RH of 55%.
The parameter shown is discharge air temprerature
in the honeycomb having the set point in the
controller of 21°F.
If the Set-Point is 21°F and the Differential is
20°F. (Set-Point) 21°F + 20°F (Differential) =
41°F. The compressor will cycle off 21°F and
back on at 41°F.
3
48
SHM-A
20° F – 25° F
