ICE MACHINES Q-Model Service Manual

Refrigeration System Section 7Safety Limit #2Refer to page 7-13 for control board identification and safety limit operation.Control Board with Black Microprocessor - Harvest time exceeds 3.5 minutes for 3 consecutive harvest cycles.orControl Board with Orange Label on Microprocessor - Harvest time exceeds 3.5 minutes for 500 consecutiveharvest cycles.Possible CauseCheck/CorrectImproper installation See “Installation/Visual Inspection Checklist” on Page 7-10Water systemWater area (evaporator) dirtyDirty/defective water dump valveVent tube not installed on water outlet drainWater freezing behind evaporatorPlastic extrusions and gaskets not securely mounted to theevaporatorLow water pressure (20 psi min.)Loss of water from sump areaClogged water distribution tubeDirty/defective water fill valveDefective water pumpElectrical systemIce thickness probe out of adjustmentIce thickness probe dirtyBin switch defectivePremature harvestRefrigeration systemNon-Manitowoc componentsWater regulating valve dirty/defectiveImproper refrigerant chargeDefective head pressure control valve (remotes)Defective harvest pressure control (HPR) valve (remotes)Defective harvest valveTXV flooding (check bulb mounting)Defective fan cycling controlSAFETY LIMIT NOTES• Because there are many possible external problems,do not limit your diagnosis to only the items listed inthis chart.• A continuous run of 100 harvests automaticallyerases the safety limit code.• The control board will store and indicate only onesafety limit – the last one exceeded.• If the toggle switch is moved to the OFF position andthen back to the ICE position prior to reaching the100-harvest point, the last safety limit exceeded willbe indicated.• If the harvest light did not flash prior to the icemachine restarting, then the ice machine did not stopbecause it exceeded a safety limit.7-16 Part No. 80-1100-3