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General steps for safe and correct unit installation.
Guidelines for selecting an appropriate location for the unit.
Describes piping, filter access, and service panel clearance.
Recommendations for mounting units on vibration isolators.
Procedures for balancing airflow and adjusting motor sheaves.
Guidelines for ductwork design and ventilation air integration.
Details on optional duct collars and filter racks.
Best practices for supply, return, and condensate piping connections.
Steps for cleaning and flushing the water circulating system.
Step-by-step guide for unit start-up and initial operation checks.
Defines acceptable ambient and water temperature/enthalpy limits.
Covers power supply, wiring, and voltage tolerance for unit operation.
Diagram for single compressor units using Mark IV/AC control.
Diagram for dual compressor units using Mark IV/AC control.
Diagram for single compressor units using MicroTech control.
Diagram for dual compressor units using MicroTech control.
Overview of the control system and basic unit operational functions.
Details the sequence of operations for Mark IV/AC control units.
Describes fault status, remote reset, and fault retry features.
Wiring for 7-day and non-programmable thermostats on specific unit sizes.
Wiring for thermostats on larger unit sizes (180-290).
Instructions for installing an optional remote sensor for thermostat integration.
Details the pump restart relay kit for loop water control integration.
Illustrates the typical installation of a motorized valve assembly.
Explains BSK features like temperature control and override for duct heaters.
Illustrates various ways to connect the auxiliary relay for different functions.
Details options like scheduled outputs, auxiliary heat, and fresh air dampers.
Steps for diagnosing when neither fan nor compressor runs.
Diagnosing issues causing the compressor to cycle rapidly.
Steps for when the compressor attempts to start but fails.
Diagnosing issues when the fan runs but the compressor does not.
Steps for when the unit provides inadequate cooling or heating.
Outlines filter changes, lubrication, and drain pan checks.
Details terms and conditions of the product warranty.
This document describes the installation and maintenance of Large Vertical Water Source Heat Pumps, ranging from 6 to 25 tons. These units are designed for indoor installation and are available in various models including LDD, LDE, LDL, LDS, LME, LMH, LML, and LMS.
The Large Vertical Water Source Heat Pumps are designed to provide heating and cooling for building spaces. Each unit incorporates a printed circuit board control system, with low voltage output from the terminal strip always at 24 volts DC. The control board also supplies 24 volts AC power to terminals C and R. These units are specifically designed to operate with a 24-volt mercury bulb type wall thermostat or a microelectronic wall thermostat selected by the manufacturer.
Single compressor units utilize a single Mark IV/AC circuit board, while dual compressor units feature two Mark IV/AC circuit boards. The refrigerant circuits in dual compressor units operate independently, allowing for total independent operation of each circuit. The Mark IV/AC circuit board includes several built-in features such as random start, compressor time delay, night setback, load shed, shutdown, condensate overflow protection, defrost cycle, brownout, and LED/fault outputs.
The low voltage terminal strip on each board is configured such that R-G energizes the fan, R-Y1 energizes the compressor for cooling, and R-W1 energizes the compressor and reversing valve for heating. The reversing valve is energized in the heating mode. A fan interlock circuit ensures the fan energizes whenever the compressor is on, even if the thermostat logic fails.
A lockout circuit on the Mark IV/AC control board stops compressor operation if any safety switches (high pressure, low pressure, or low temperature) open. If the low temperature switch opens, the unit enters cooling mode for 60 seconds to defrost the water-to-refrigerant heat exchanger before locking out the compressor. If the condensate sensor detects a filled drain pan, compressor operation is suspended only in cooling mode. The unit can be reset by opening and closing the disconnect switch on the main power supply. The Mark IV/AC control board also provides a fault output signal to an LED on a wall thermostat, indicating various fault conditions.
The system supports night setback operation, activated by a "grounded" signal to the "U" terminal on the low voltage terminal strip. This shuts off the fan and places the unit under control from the night setback terminal on the thermostat. For dual compressor units, W2 on single compressor and W3 on dual compressor units are used for day heating and cooling operation, with load shed and shutdown operations activated by a "grounded" signal to the "L" and "E" terminals, respectively.
The P and C terminals on the Mark IV/AC board are used for pump restart, passing a voltage signal when the unit's compressor is on. This signal can be detected by a Pump Restart Relay board to control heat pump loop circulation pumps, especially during unoccupied periods.
MicroTech 2000 units offer up to four configurable outputs for various control signals:
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