McQuay MHC Standard Range User Manual

IM 985-1 / Page 13 of 36
Mechanical (Compressor) Heating Override
to Electric Heat Operation
Note: Only with units equipped with the electric
heat feature
In
the event of a compressor failure or, electric heat is
desired over mechanical (compressor) heating, a factory
certiedservicetechnicianmayrecongurethemaleand
female plugs to enable electric heat. This option allows
emergency electric heat when mechanical heating is not
available. Electric heat can be disabled and the unit can be
returned to mechanical (compresssor) heating operation
when desired (Figure 11).
Note: In electric heat mode, unit will not run
compressor on a call for heating. The electric heater
will be utilized instead.
Before disconnecting or connecting plugs, be sure power
to unit is off and power disconnect switch is in the off position.
Switching Mechanical (Compressor) Heating to
Electric Heat Operation
1. Disconnect wires 70 and 71 plug located on outside
of control box from socket that connects to the
Entering Water Temperature (EWT) Sensor (Figure
11).
2. Reconnect wires 70 and 71 plug into the Electric
Heat (EH) socket located on the back of the hinged
control box (Figure 11).
3. Coil the disconnected Entering Water Temperature
Sensor wire and store in safe location for later use.
Figure 11. Switching to Electric Heat Detail
Table 3. Electric Heater Current and Power
Electrical Data
General
1. Be sure the available power is the same voltage and
phase as that shown on the unit serial plate. Line and
voltage wiring must be done in accordance with
local codes or the National Electrical Code,
whichever is applicable.
2. Apply correct line voltage to the unit. A disconnect
switch near the unit is required by code. Power
to the unit must be sized correctly and have dual
element (Class RK5) fuses or HACR circuit breaker
for branch circuit overcurrent protection. See the
nameplate for correct ratings.
3. All 208-230V single phase units are factory wired
for208voltoperationunlessspeciedfor230volts.
Operating Voltages
115/60/1 . . . . . . . . 104 volts min.; 127 volts max.
208-230/60/1 . . . . 197 volts min.; 253 volts max.
265/60/1 . . . . . . . . 238 volts min.; 292 volts max.
230/50/1 . . . . . . . . 197 volts min.; 253 volts max.
Note: Voltages listed are to show voltage range.
However, units operating with over voltage and under
voltage for extended periods of time will experience
premature component failure.
Operating Limits
Environment
This equipment is designed for indoor installation
only.
Sheltered locations such as attics, garages,
etc.,generallywillnotprovidesufcientprotection
against extremes in temperature and/or humidity, and
equipment performance, reliability, and service life may
be adversely affected.
Sizes 007, 009, 012 Sizes 015, 018
Nominal Voltage
2.5kW 3.5kW
Power (kW) Current (Avg) Power (kW) Current (Avg)
208 2.01 9.67 2.71 13.02
230 2.46 10.70 3.31 14.40
240 2.68 11.16 3.61 15.03
265 3.27 12.33 4.40 16.59
277 3.57 12.88 4.80 17.35
WARNING

McQuay MHC Standard Range Specifications

General

Brand	McQuay
Model	MHC Standard Range
Category	Heat Pump
Language	English