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Verify that all electrical connections (both main power and control wiring) have been properly secured and all access covers
replaced.
Check to be sure that all field piping has been insulated, properly supported and secured with clamps.
Confirm that the TXV sensing bulb has been securely fastened to the suction line and insulated.
Verify that all condensate drain line piping has been completed, all piping is properly pitched, supported and secured with
clamps. On low temperature applications make sure that all drain line piping is insulated, drain line heaters are installed and
wired to a dedicated power source for continuous operation.
Check to be sure that all pipe and conduit penetrations into the cooler / freezer have been properly sealed to prevent the infil-
tration or warm, moist air into the conditioned space. Unsealed gaps or voids will quickly become "conduits" through which
moisture laden outside air will flow into the cooler or freezer placing an unnecessary burden on the refrigeration system and
potentially creating both safety concerns for operating personnel as well as operation problems for the unit cooler, (ex. coil ic-
ing / steaming, stalled / burned out fan motors, broken fan blades, liquid flood back to the compressor, etc.).
Measure the incoming voltage at the main power terminal block. Voltage measured should be within +/- 10% of the unit name-
plate rating.
On initial start up and pulldown of a warm box (electric defrost units only) the defrost termination / fan delay control will hold out
the fans until the coil temperature reaches (and continuously maintains) approx. +25 degrees F (+/-). Prior to start up of these
units a wire jumper should be physically installed between terminals 1 and 3 on the power terminal board which will temporarily
bypass the fan delay side of the switch - forcing the fans to run continuously. Once the room temperature has dropped down
near freezing the jumper wire should be removed for proper operation.
Once the unit is running check all fan motors for proper rotation and air throw. If poor air circulation is noted refer to page 7 of
this manual for possible causes and correction of air flow issues.
Observe the unit for any unusual noise or vibration. Investigate and correct the cause of any issues noted.
With the system fully charged with refrigerant and the room at or near design operating temperature check superheat at the
evaporator coil outlet. Adjust the expansion valve (if required) to obtain correct, operating superheat (see EVAPORATOR SU-
PERHEAT - Page 12).
Check for any standing water in the condensate drain pan. If the drain pan is holding water check for proper P-traps in the line
(in the absence of a trap, negative pressure at the drain pan connection fitting can cause water to hold up in the pan). Verify
unit is mounted level. Check drain line piping for correct pitch or possible obstructions / debris and correct as required.
On electric defrost units manually force system into a defrost cycle. Check the amp draw of the heaters and compare this
reading to the unit rating label in order to verify that all defrost heaters are functioning correctly. Allow the system to operate
through a complete defrost cycle and observe that the unit terminates the defrost cycle on the defrost termination temperature
control (approx. +70 degrees +/-). Observe that the fans are delayed no more than approx. (2) minutes immediately following
the defrost cycle.
Adjust the system defrost control / timer to periodically initiate a defrost cycle. For "Air Defrost" or off cycle timers a typical set-
ting would be 2-3 times per day for 45 minutes per cycle. Electric defrost timers are typically set to provide (4) 30 minute de-
frost cycles per day however it should be noted that every installation is potentially different and that defrost is a "necessary
evil". Generally speaking fewer defrost cycles per day is always better - particularly if any steaming is observed near the end of
the defrost cycle. Steaming is characterized by a hissing sound which is caused by water droplets as they contact an over-
temp heater sheath and immediately vaporize into steam which then condenses on any adjacent cold surfaces such as fan
panels, drain pans, fan blades, motor mounts, ceiling panels, etc.. Although in many cases a technicians initial reaction is to
increase or lengthen the defrost cycle the exact opposite is usually the best course of corrective action. Reduce the number of
cycles per day and verify the cycle is being terminated by the defrost termination temperature control (Refer to Troubleshoot-
ing Defrost Cycle - Page 22).
Tecumseh designed by LU-VE unit coolers are designed to operate with the following commonly used refrigerants;
For field retrofit applications it is also generally acceptable to use R-438A, R-449B or similar field service replacement refrigerants
which have been designed to closely match the operating characteristics of the original refrigerant they replace.
Unit coolers may also be custom designed / circuited for use with other fluids such as water or glycol
The maximum working pressure of all units using copper tube coils is 350 PSIG. The maximum, recommended unit test
pressure for field leak testing purposes is 150 PSIG.
Note: Always verify the maximum test pressure rating of any connected valves, controls (ex. solenoids, expansion valves,
pressure transducers, etc.) to avoid possible damage to these components during pressure testing.
Check The Following Items Before And After Initial Start Up
IMPORTANT NOTES AND INFORMATION
R-404A, R-507, R-134A; R-407A, R-407C, R-407F, R-448A and R-449A
START UP
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