Hoshizaki MWH KM-515MAH G Control Board Settings, S4 Dip Switch Setting, Pump-Out, Frequency

f)Refrigerant Pressures, HM, and TXV Diagnosis: If evaporator is still not cooling, check refrigerant pressures. See "VIII.B. Performance Data."

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.B. Performance Data." 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.B. Performance Data."

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 CV is not leaking by (water flowing down the potable drain). If CV is leaking by, remove and clean CV, replace rubber seat and spring if necessary. If water tank is full, see "II.E. Float Switch Check and Cleaning." for erratic operating FS.

7)Pump-Out Cycle – LEDs 1, 3, and 2 are on (10/20 second pump-out).Timing of the first pump-out is determined by S4 dip switch 5 & 6. See the table below.

"G" Control Board Settings

S4 Dip Switch Setting		Pump-Out	"G" Control Board
No. 5	No. 6	Frequency
OFF	OFF	Every cycle	After 2nd freeze cycle
ON	OFF	Every 2 cycles	After 3rd freeze cycle
OFF	ON	Every 5 cycles	After 6th freeze cycle
ON	ON	Every 10 cycles	After 11th freeze cycle

Comp and FMR continue, HGV energizes. If S4 dip switch 3 & 4 are set to 3 off and 4 on, LED 4 turns on and WV and X11 relay energize, energizing X10 relay.

NOTICE! S4 dip switch 3 & 4 must not be set to 3 off and 4 on. Otherwise, PM will rotate in freeze cycle direction instead of pump-out direction. FM and LLV de‑energize. PM stops for 2 sec., then reverses for 10/20 sec. depending on pump‑out timer (S4 dip switch 3 & 4) setting. When the pump‑out timer terminates, pump‑out

28