Hoshizaki KM-350MWJ Service Manual page 19

d) PM Diagnosis: Confirm water is flowing over evaporator from PM and not WV. If PM
de-energizes once freeze begins, check for 115VAC at CB K1 #4 (R) to neutral (W).
If 115VAC is not present, replace CB. If 115VAC is present and PM is de-energized,
check PM capacitor and motor winding continuity.
e) FM and LLV Diagnosis: If FM or LLV does not energize, check for 115VAC at CB
K1 #3 (BK) to neutral (W). If 115VAC is not present and LED 2 is on, check for
115VAC at CB K1 #1 (V). If 115VAC is present at #1 (V) and not at #3 (BK), replace
CB. If 115VAC is present and LED 2 is on:
For FM, check capacitor, motor winding, and blade for binding.
For LLV, check coil voltage and continuity.
Note: LED 2 is on for LLV/FM and off for HGV.
f) Refrigerant Pressures, HM, and TXV Diagnosis: If evaporator is still not cooling,
check refrigerant pressures. See "VIII.A. Specification and Performance Data
Sheets."
Next, check HM operation. If refrigeration pressures are above HM setpoint and
HM is bypassing, replace HM. Check TXV for proper operation. Remove TXV bulb
and hold it in your hand, refrigerant low-side pressure should rise, place TXV bulb in
ice water, refrigerant low-side pressure should drop. A 10 to 15 pound pressure swing
between warm and cold conditions indicate a good TXV. If a 10 to 15 pound swing is
not present, replace TXV.
g) WRV Diagnosis: WRV is factory set and generally no adjustment is required.
If WRV fails to open in freeze, check for proper refrigerant pressures. See "VIII.A.
Specification and Performance Data Sheets." If refrigerant pressures are correct and
WRV does not open, adjust or replace as needed. See "IV.C. Water Regulating Valve
Adjustment (water-cooled models)."
h) Freeze Termination Diagnosis: After 5 min. in freeze, disconnect CB K5 FS
connector. 15 sec. later appliance should switch out of the freeze cycle (15 second
delay after FS opens before terminating the freeze cycle). If appliance remains in
freeze longer than 15 sec. after FS removed, replace CB. If appliance switches with
FS removed but would previously not switch out of freeze with FS connected (long
freeze - 3 beep alarm), see "II.E. Float Switch Check and Cleaning."
Note: Normal freeze cycle will last 20 to 40 min. depending on model and conditions.
Cycle times and pressures should follow performance data provided in this
manual. See "VIII.A. Specification and Performance Data Sheets."
i) Short Freeze Cycle Diagnosis: Confirm water tank fills and overflows during 1 min.
fill and harvest cycles. If not, check water supply filters, shut-off valve, WV screen.
If water tank empties before 5 min. timer terminates and freeze cycle is short, check
that DV is not leaking by (water flowing down the drain). If DV is leaking by, remove
and clean DV, replace if necessary. If water tank is full, see "II.E. Float Switch Check
and Cleaning." for erratic operating FS.
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