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IM 934-5
Page 41 of 48
Recommended Spare Parts
An inherent advantage of the Incremental system is that
failure of any part affects only one incremental conditioner
and does not interrupt the operation of the rest of the system.
A further advantage is that a failed part can be quickly and
easily replaced, thus minimizing the inoperative time of the
equipment. This is so, however, only if a replacement part
is quickly available. In order to replace a failed part quickly
and keep all incremental conditioners in good operating
condition, Daikin McQuay recommends that at the time
incremental conditioners are purchased, owners arrange for a
small stock of replacement parts.
Where an owner carries such a stock, immediate replace-
ment of defective parts is possible. The defective part
can then be returned to Daikin McQuay warranty parts.
As long as it is still in warranty, it is repaired or replaced
and returned to the owner with out cost for shop labor and
material. Thus, the stock of replacement parts is constantly
replenished. Below is a list of the kinds of parts which
Daikin McQuay recommends to be carried in stock together
with the quantity of parts recommended per 100 incremental
conditioners installed.
Cooling Chassis
..............................................................
2
Compressor Overload Device
........................................
2
Compressor Running Capacitor
.....................................
2
Fan Motor. Capacitor
......................................................
2
Control Board
.................................................................
2
Thermostat
......................................................................
2
Control Relay (if used)
...................................................
2
Damper Motor (if auto damper)
.....................................
2
Electric Resistance Heater (if electric heat)
...................
2
Touch-up Paint (1 pt. spray can)
....................................
2
For the current spare parts list, and applicable prices, see
your Daikin McQuay representative or write Daikin Mc-
Quay Service, P.O. Box 1551, Minneapolis, MN 55440.
Refrigeration Cycle
Every motor-driven refrigeration system operates on the car-
not cycle. A practical understanding of what goes on at the
various steps in this cycle can be a big help to the trouble-
shooting mechanic. Figure 41 illustrates the refrigeration
cycle. The diagram shows what occurs in each component of
a hermetically sealed system as used in all Daikin McQuay
Air Conditioning equipment. The temperatures shown are
typical of what they might be when the air entering the
condenser (outdoor temperature) is 95°F, (350 C) and the
temperature of the conditioned space is 80°F (270 C).
Figure 40: Refrigeration Cycle
95°F. (35°C.)
Outdoor Air to Condenser
60.3 psia (416 kPa)
& 60°F. (15.5C.)
to Compressor (Gas)
Hermetic
Compressor
60°F. (15.5°C.)
Conditioned Air to Room
80°F. (27°C.)
Room Air to Evaporator
45°F. (7°C.)
R-410A (Liquid and Gas)
to Evaporator
120°F. (49°C.) Condenser Air
to Outdoors
110°F. (43°C.)
Liquid R-410A to
Capillary
Capillary
Restrictor
Condenser
418.3 psig (2884.1 kPa) R-410A
to Condenser (Hot Gas)
Evaporator
Summary of Contents for McQuay IM 934-5
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