McQuay LML User Manual

The auxiliary relay is designed to interface external equip-
ment with the Mark IV/AC board. The auxiliary relay has been
provided with the components necessary to protect from
electrical damage that may occur to the Mark IV/AC board
when using standard off-the-self relays. The auxiliary relay
Auxilliary Relay (P/N 03005073)
Operation: In this example the auxiliary relay contacts can be used
to indicate a fault condition. With the auxiliary relay connected as
shown, the normally open contacts will close during a fault condition.
Operation: In this example the auxiliary relay contacts can be used
to signal WSHP fan operation to another device. In this example when
the thermostat energizes the “G” terminal the auxiliary relay normally
open contacts will close.
Operation: In this example the auxiliary relay is used to interface other
control devices to the Mark IV/AC board. Using the Orange (-) and
White (+) wires, and 24vac or 24vdc, another device could be used to
start and stop the WSHP heating sequence.
can be used to provide fault signals, unit operation signals,
or to provide a means for remote equipment to control the
Mark IV/AC board. The orange, yellow, and white connec-
tions are short flying leads pre-attached to the board. The
diagrams shown are some connection examples.
IM 439 / Page 21
WSHP Mark IV/AC Board Low Voltage Terminal Strip
OW2GW1Y1 F E LUAPVRC
1
2
3
Auxiliary Relay
Orange
Yellow
White
WSHP Mark IV/AC Board Low Voltage Terminal Strip
OW2GW1Y1 F E L U A P V R C
1
2
3
Auxiliary Relay
Orange
Yellow
White
WSHP Mark IV/AC Board Low Voltage Terminal Strip
OW2GW1Y1 F E L U A P V R C
1
2
3
Auxiliary Relay
Orange
Yellow
White

McQuay LML Specifications

General

Brand	McQuay
Model	LML
Category	Heat Pump
Language	English

Summary

Installation Procedures

General Installation Procedures

General steps for safe and correct unit installation.

Unit Location Requirements

Guidelines for selecting an appropriate location for the unit.

Unit Arrangement and Filter Access

Describes piping, filter access, and service panel clearance.

Vibration Isolation Methods

Recommendations for mounting units on vibration isolators.

Air Balancing and Sheave Adjustment

Procedures for balancing airflow and adjusting motor sheaves.

Ductwork and Ventilation Air

Guidelines for ductwork design and ventilation air integration.

Optional Ductwork Accessories

Optional Duct Collar and Filter Rack

Details on optional duct collars and filter racks.

Piping and System Flushing

Piping Installation Guidelines

Best practices for supply, return, and condensate piping connections.

System Cleaning and Flushing

Steps for cleaning and flushing the water circulating system.

Start-up Procedures

Initial Start-up and Operation Checks

Step-by-step guide for unit start-up and initial operation checks.

Operating Limits and Electrical Data

Operating Environment and Limits

Defines acceptable ambient and water temperature/enthalpy limits.

Electrical Installation and Voltage Limits

Covers power supply, wiring, and voltage tolerance for unit operation.

Typical Wiring Diagrams

Mark IV/AC Single Compressor Wiring

Diagram for single compressor units using Mark IV/AC control.

Mark IV/AC Dual Compressor Wiring

Diagram for dual compressor units using Mark IV/AC control.

MicroTech Single Compressor Wiring

Diagram for single compressor units using MicroTech control.

MicroTech Dual Compressor Wiring

Diagram for dual compressor units using MicroTech control.

Unit Operation and Control

General Unit Operation Overview

Overview of the control system and basic unit operational functions.

Mark IV/AC Control Sequence

Details the sequence of operations for Mark IV/AC control units.

Mark IV/AC Control Features and Faults

Describes fault status, remote reset, and fault retry features.

Thermostat Connection Diagrams

Thermostat Wiring for 070-121 Units

Wiring for 7-day and non-programmable thermostats on specific unit sizes.

Thermostat Wiring for 180-290 Units

Wiring for thermostats on larger unit sizes (180-290).

Optional Remote Sensor Installation

Instructions for installing an optional remote sensor for thermostat integration.

Miscellaneous Options

Pump Restart Relay Kit Installation

Details the pump restart relay kit for loop water control integration.

Motorized Valve and Relay Options

Motorized Valve Installation Guide

Illustrates the typical installation of a motorized valve assembly.

Boilerless System Kit (BSK)

BSK Functionality and Control

Explains BSK features like temperature control and override for duct heaters.

Auxiliary Relay Features

Auxiliary Relay Connection Examples

Illustrates various ways to connect the auxiliary relay for different functions.

Field Installed MicroTech Options

MicroTech Output Signal Configuration

Details options like scheduled outputs, auxiliary heat, and fresh air dampers.

Troubleshooting Guide

Unit Not Running Troubleshooting

Steps for diagnosing when neither fan nor compressor runs.

Compressor Cycling Troubleshooting

Diagnosing issues causing the compressor to cycle rapidly.

Compressor Start Failure Troubleshooting

Steps for when the compressor attempts to start but fails.

Fan Operation, No Compressor Troubleshooting

Diagnosing issues when the fan runs but the compressor does not.

Insufficient Cooling/Heating Troubleshooting

Steps for when the unit provides inadequate cooling or heating.

Maintenance and Warranty

Routine Maintenance Procedures

Outlines filter changes, lubrication, and drain pan checks.

Product Warranty Information

Details terms and conditions of the product warranty.