Hoshizaki Commercial Series Service Manual page 26

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b) Cool Down Diagnosis: Confirm that Comp and ConFM energize and cabinet
temperature appears on DM. If not, confirm 115VAC between CM L3 and CM N5. If
115VAC is not present, confirm wiring connections are secure for both the power wire
(CM L3) and the neutral wire (CM N5). If 115VAC is present and DM is off, check that
the display cable between CM and DM is not disconnected; reconnect if loose. If DM
is still off, CM or DM may be bad, so replace both. Next, check that Comp and ConFM
are energized. If not, check for 115VAC between CM C1 and CM N5. If 115VAC is
present between CM L3 and CM N5 (above) and not between CM C1 and CM N5,
check CTh status. See "IV.C.Thermistor Check." If CTh ohm reading is in proper range,
CM is bad and must be replaced. If 115VAC is present between CM C1 and CM N5,
check for 115VAC on CR coil (terminals 5 and 6). If 115VAC is not present between
CR 5 and CR 6, check continuity of HPS. If open, allow time for HPS to reset. If HPS
does not reset, replace HPS and diagnose reason for HPS activation. See "IV.A.2.7)c)
HPS Activation." If 115VAC is present between CR 5 and CR 6, and Comp and ConFM
are not energized, check CR contact continuity. If open, CR is defective and must be
replaced. If CR is good and Comp or ConFM are not energized, check for 115VAC at
Comp terminals, Comp overload (internal on 1-section), start components, and Comp
and ConFM motor winding continuity.
If Comp and ConFM are energized and the cabinet does not cool down, check for a
restriction in the refrigeration circuit, correct TXV operation (if applicable), and correct
refrigerant charge.
c) HPS Activation: Confirm ConFM is energized and fan blade turns freely. Check that the
condenser coil is not clogged or restricted. Check that there are no restrictions in the
refrigeration circuit (drier, TXV).
Confirm that the location meets factory requirements:
• This unit is not intended for outdoor use. Normal operating ambient temperature should
be within 45°F to 100°F (7°C to 38°C).
• The unit should not be located next to ovens, grills, or other high heat producing
equipment.
• The unit should not be located in a corrosive environment.
• The unit should be a minimum of 4" (11 cm) from side walls.
• A minimum of 10" (25 cm) overhead clearance should be provided for proper ventilation.
8) Cool Down Achieved–CTh cools to 3°F (1.7°C) below setpoint. EvapFM, MH, and
PH continue. Comp and ConFM de-energize. Diagnosis: If Comp and ConFM do not
de-energize, confirm CTh status. See "IV.C. Thermistor Check." If CTh ohm reading is in
proper range and Comp and ConFM do not de-energize, CM is defective and must be
replaced.
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