Service manual

33
Installation and Service Manual
COMPONENT DIAGNOSTICS
TOTAL ICE CAPACITY / ICE PRODUCTION CHECK
Thermostatic Expansion Valve(s)
The following suggestions are made with the under-
standing that:
A) The condenser and fan blade are clean and have
proper operating conditions.
B) Water supply to the product is correct and water
flow over the evaporator is correct.
C) System charge is correct.
D) TXV bulb is properly located and secured to the
line and correctly insulated.
E) Hot gas valve(s) not leaking through.
F) Discharge pressure OK.
Starving Valve - Product Symptoms:
1. Suction pressure lower than normal for the op-
erating conditions.
2. Ice production lower than normal and/or none.
3. Ice pattern on evaporator (if any) thin at top and
thick at bottom.
Flooding Valve - Product Symptoms:
1. Ice production lower than normal or none.
2. Suction pressure stabilizes at higher than nor-
mal and does not continue to modulate and de-
cline (may start to slowly rise).
3. Ice pattern will be very thick from top to bottom
of evaporator - unit may not enter harvest.
4. Frost on the suction line is normal on medium
temperature refrigeration equipment. Frost ex-
tending onto the compressor shell may not be a
problem. Before checking the sealed system,
check external conditions such as spacing
around poor ventilation, dirty condenser, etc.
CAUTION:
A) On models with the expansion valve bulb clamped to
a vertical section of the suction line - capillary tube
should point upward. This is done to eliminate the
possibility of contaminates from plugging capillary
tube. DO NOT RELOCATE THE BULB.
B) Superheat settings and bulb charges are designed
specifically for Servend ice makers, and vary by model
and refrigerant used. Be sure to replace expansion
valves by part number and with Servend parts only.
Total Ice Capacity
Ice capacity of any ice maker is affected by many
operating conditions, such as water and air temperatures
and location factors. Please review the capacity tables
in this manual for average 24 hour capacity under vari-
ous conditions. All printed capacity ratings are +/- 10%
except 50 HZ units.
50 HZ units cycle time will increase by approximately
12% and capacity will decrease by approximately 17%.
Ice Production Check
Take air temperature, if air-cooled condenser, at the
inlet of condenser, 2" from condenser fins.
Incoming water temperature at the outlet of the float valve.
Cycle time (CT) = Freeze time + harvest time, in minutes.
1440 divided by CT = number cycles per 24 hours.
Weight of ice from one cycle in pounds.
EXAMPLE:
Weight x cycles/day = total production/24 hours
Compare your known facts to the production tables
found in the product service manual.