Hoshizaki KM515MAH-E ICE MAKER

[Gary S]

Hi all,

Briefly looked at the above ice machine today. Last engineer had a iced up evap and he cleared it and was ok for a day or 2. This happened in the last week. I got there today and was bleeping twice to indicate defrost took over 20 mins. Reset PCB and unit came on but stayed on defrost. Hot gas sol valve and compressor are ok so pretty sure the thermistor on suction pipe is out. When i checked the thermistor and removed from pipe clamp the defrost cycle stopped and made a batch of ice.
Anyone know what value the thermistor should be reading on ohmmeter at different temps?
also is this thermistor involved in ice production or is that done by pcb on this model?

Many thanks in advance

[Gary S]

Just found info on hosizaki website the float switch terminates freeze cycle and thermistor should be approx 3.9 k ohms at 9 degrees c.
Hope this helps someone out in future

[install monkey]

http://www.mediafire.com/view/46t3ok...80050b-web.pdf
click on link for manual- for future ref

[nike123]

Prolonged defrost could indicate lack of refrigerant.

[cateyes]

Check to make sure that ice isn't developing inside evaporator between the stainless steel sheets where evaporator tubing is routed before defrost. If you do see ice accumulated then it probably is the water solenoid leaking by during production. This will effect defrost cycle due to additional load forcing it to time out.

[cateyes]

edit: water solenoid "VALVE" leaking by during production.

[Magoo]

not too sure of that model machine, but they generally have a discharge to liquid line by pass valve that are prone to failure, and screw up evap pressures with low ambient temps, and create situation you have currently.