Hoshizaki AMERICA 73183 - Manual (Page 20)

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Defrost Diagnosis:
1a) Temperature/Time-Initiated: Has DTh cooled to 32°F (0°C) or lower? Before
proceeding, confirm DTh status. See "II.D. Thermistor Check." Has 4-hr. Comp
cumulative run timer satisfied?
(1) DM Diagnosis: Confirm "dEF" appears on DM. If not, replace CM and DM with
HS kit.
(2) DH and DrH Diagnosis: Confirm DH and DrH energize. If not, check for 115VAC
at CM H4 (BK) to neutral (W). If 115VAC is not present, replace CM and DM with
HS kit. If 115VAC is present, check DT continuity. If open, let cool and reset. If DT
does not close, replace DT. If DT is closed, check DH and DrH amp draw and
continuity.
(3) Comp and ConFM Diagnosis: Confirm Comp and ConFM de-energize. If not,
check for 115VAC at CM C1 (R) to neutral (W). If 115VAC is present, replace CM
and DM with HS kit. If 115VAC is not present and Comp and ConFM continue,
check CR#1 (R) to neutral. If 115VAC is present, replace CR.
(4) EvapFM Diagnosis: Confirm EvapFM de-energizes. If not, check for 115VAC at
CM F6 (BK) to neutral (W). If 115VAC is present, replace CM and DM with HS kit.
1b) Manually-Initiated: After pressing the lower button for 5 sec., check the following:
(1) CM and DM Diagnosis: Confirm "dEF" appears on DM. If not, replace CM and
DM with HS kit.
(2) DH and DrH Diagnosis: Confirm DH and DrH energize. If not, check for 115VAC
at CM H4 (BK) to neutral (W). If 115VAC is not present, replace CM and DM with
HS kit. If 115VAC is present, check DT continuity. If open, let cool and reset. If DT
does not close, replace DT. If DT is closed, check DH and DrH amp draw and
continuity.
(3) Comp and ConFM Diagnosis: Confirm Comp and ConFM de-energize.
If not, check for 115VAC at CM C1 (R) to neutral (W). If 115VAC is present,
replace CM and DM with HS kit. If 115VAC is not present and Comp and ConFM
continue, check CR #1 (R) to neutral (W). If 115VAC is present, replace CR.
(4) EvapFM Diagnosis: Confirm EvapFM de-energizes. If not, check for 115VAC at
CM F6 (BK) to neutral (W). If 115VAC is present, replace CM and DM with HS kit.
2a) Temperature/Time Initiated Defrost-Termination: Has DTh warmed to 59°F
(15°C)? If not yet confirmed, confirm DTh status. See "II.D. Thermistor Check." If
DTh is in proper range, DH de-energizes and 3 delay timers start. If DTh has not
warmed to 59°F (15°C), check DT and DH continuity. Next, check DH amp draw.
(1) 3-min. Comp delay timer terminates: 3 min. after DH de-energizes, confirm
Comp and ConFM energize. If not, confirm cabinet temperature is warm enough
for Comp and ConFM operation. Next, check for 115VAC at CM C1 (R) to
neutral (W). If 115VAC is not present, check CTh status. See "II.D.Thermistor
Check." If CTh ohm reading is in proper range, replace CM and DM with HS kit.
If 115VAC is present, check for 115VAC at CR #4 (BK) to neutral (W) and
CR #1 (R) to neutral (W). If 115VAC is present at CR #4 (BK) to neutral (W) but
not at CR #1 (R) to neutral (W), replace CR. If 115VAC is present at CR #1 (R)
and Comp or ConFM are not energized, check Comp start components, Comp
protector (internal on 1-section, external on 2-section), and Comp motor winding
continuity. If ConFM is not energized, check ConFM fan blades for binding and
motor winding continuity.