Standard Operation Conditions; Start-Up - McQuay MWSC 010 Series Manual

Standard Operation Conditions

Temperature
Minimum indoor air temperature
Maximum indoor air temperature
Minimum outdoor air temperature
Maximum outdoor air temperature
Ts : Dry bulb temperature.
Th : Wet bulb temperature.

Start-up

Open all valves to full open position and turn on power to the conditioner.
1. Set mode to "Cool". Set the cooling temperature to the coolest position. Again, many conditioners have time delays
which protect the compressor(s) against short cycling. After a few minutes of operation, check the discharge
grilles for cool air delivery. Measure the temperature difference between entering and leaving water. It should
be approximately 1 1/3 times greater than the heating mode temperature difference. For example, if the cooling
temperature difference is 6°C, the heating temperature difference should have been 5°C.
Without automatic fl ow control valves, target a cooling temperature difference of 5°C to 8°C. Adjust the combination
shut off/balancing valve in the return line to a water fl ow rate which will result in the 5°C to 8°C difference.
2. Set mode to "Heat". Set the heat setting to the warmest selection. Some conditioners have built-in time delays
which prevent the compressor from immediately starting. With most control schemes, the fan will start immediately.
After a few minutes of compressor operation, check for warm air delivery at discharge grille. If this is a "cold
building" start-up, leave unit running until return air to the unit is at least 18°C. Measure the temperature difference
between entering and leaving air and entering and leaving water. With entering water of 16°C to 27°C leaving
water should be 3.3°C to 6.6°C cooler, and the air temperature rise through the machine should not exceed 19°C.
If the air temperature exceeds 19°C, then the water fl ow rate is inadequate.
3. Check the elevation and cleanliness of the condensate line. If the air is too dry for suffi cient dehumidifi cation,
slowly pour enough water into the condensate pan to ensure proper drainage.
4. If the conditioner does not operate, check the following points:
a. Is supply voltage to the machine compatible?
b. Is thermostat type appropriate?
c. Is thermostat wiring correct?
5. If the conditioner operates but stops after a brief period:
a. Is there proper airfl ow? Check for dirty fi lter, incorrect ductwork.
b. Is there proper water fl ow rate within temperature limits? Check water balancing; back fl ush unit if dirt clogged.
6. Check for vibrating refrigerant piping, fan wheels, etc.
7. Do not lubricate the fan motor during the fi rst year of operation as it is lubricated at the factory.
Ts (°C) Th (°C)
19.4 13.9
26.7 19.4
19.4 13.9
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