McQuay MHC Series, Installation & Maintenance Data, Page: 2 / 36

Page 2 of 36 / IM 985-1
Model Nomenclature
NOTE: For illustration purposes only. Not all options available with all models.
Please consult McQuay Sales Representative for specific availability.
Product Category
W = WSHP
Product Identifier
MHC = Standard Range Console WSHP
MHW = Geothermal Range Console WSHP
Design Series
1 = A Design
2 = B Design
3 = C Design
4 = D Design
Nominal Capacity
007 = 7,000 BTU/h
009 = 9,000 BTU/h
012 = 12,000 BTU/h
015 = 15,000 BTU/h
018 = 18,000 BTU/h
Controls
B = MicroTech III Unit Controller
C = MicroTech III Unit Controller w/L
on
W
orks
C
ommunication Module
D = MicroTech III Unit Controller w/BACnet Communication Module
Voltage
A = 115/60/1
E = 208-230/60/1
J = 265/60/1
Cabinet Type
F = Flat Top
S = Slope Top
Discharge Grille
2 = Standard Stamped
Louver
3 = Multi-Directional Grille
Blower Motor
01 = Standard
Discharge Air
T = Top
Return Air
B = Bottom Return (High Sill)
F = Front Return (Low Sill)
Cabinet Height
H = High Sill
L = Low Sill
W MHC 1 009 B E H B T 01 F2
Table of Contents
­Model­Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Receiving­and­Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pre-Installation­­ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Physical­Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Unit­Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
­
Piping­ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-11
­ Cleaning­&­Flushing­Water­System . . . . . . . . . . . . . . . 11
­ Electrical­Connections­ . . . . . . . . . . . . . . . . . . . . . . 12-22
­ Mechanical­(Compressor)­Heating­Override­to
­ Electric­Heat­Operation­ . . . . . . . . . . . . . . . . . . . . . . . . 13
­ Electrical­Data­(General)­ . . . . . . . . . . . . . . . . . . . . 12-13
­ Operating­Voltages­ . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
­ Operating­Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-14
­ MicroTech­III­Unit­Controller­ . . . . . . . . . . . . . . . . 14-25
­ I/O­Expansion­Module . . . . . . . . . . . . . . . . . . . . . . . . . 15
­ MicroTech­III­Controller­with­L
on
­Module . . . . . . . . . 16
­ MicroTech­III­Controller­with­BACnet­Module­ . . . . . 17
­ MicroTech­III­Unit­Controller­Terminal­Locations­&
­ Descriptions­ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
­ MicroTech­III­Unit­Controller­Terminal­Locations­ . . . 19
­ L
on
W
orks
Communication­Module­Placement­ . . . . . 20
Typical­Wiring­Diagrams . . . . . . . . . . . . . . . . . . . . . . . . 22-23
Start-up­ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Additional­Accessories­(General)­ . . . . . . . . . . . . . . . . . . . . 24
­
Thermostats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-29
­ Motorized­Isolation­Valve­&­Relay­ . . . . . . . . . . . . . . . 29
­ Pump­Restart­Kit­ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
­ Multiple­Unit­Control­Panel­(MUCP)­for­Use­With­
MicroTech®­III­Unit­Controller . . . . . . . . . . . . . . . . . . 29
­ Outside­Air­Dampers­ . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-34
­
The­in­and­outs­of­R-410A . . . . . . . . . . . . . . . . . . . . . . 31
­ Lubrication­ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
­ General­Maintenance­ . . . . . . . . . . . . . . . . . . . . . . . . . . 31
­ Troubleshooting­Refrigeration­Circuit . . . . . . . . . . . . . 32
­ ­ Cooling­Refrigeration­Circuit­ . . . . . . . . . . . . . . . . 33
­ ­ Heating­Refrigeration­Circuit­ . . . . . . . . . . . . . . . . 33
­ Troubleshooting­The­WSHP­Unit­Operation . . . . . . . . 34
­ Troubleshooting­the­MicroTech­III­Unit­Controller . . . 35
­ ­ LED­Status­&­Faults­
­ ­ Troubleshooting­Reference­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­ .­35
WARNING
This Installation and Maintenance bulletin is intended to provide the proper procedures for installing a McQuay Console
Water Source Heat Pump. Failure to follow these procedures can cause property damage, severe personal injury or death.
Additional, failure to follow these procedures can cause premature failure of this equipment or cause erratic unit operation,
resulting in diminished unit performance. Disregarding these directions may further lead to suspension or revocation of the
manufacturer's warranty.