1. Trane Ucp Module Manual Diagram

Installation

Unit Control Module (UCM) 4.2 Retrofit

Model VAV

Models

ReliaTel™ Refrigeration Module (RTRM) is a standard component of the unit. This is the heart of the system, the computer and program reside in this module. The typical basic stand-alone system will include the ReliaTel™ and ZSM. Zone Sensor Module (ZSM) is an accessory component and replaces a thermostat. It provides operator. Unitary Control Processor (UCP), is a standard compo-nent of the unit. This is the heart of the system, the computer and program reside in this module. The typical basic stand alone system will include the UCP and a Zone Sensor Module. Zone Sensor Module (ZSM), is an accessory component and replaces a thermostat. It provides operator.

“A” and later Design Sequence

VAV

NOTICE:

Warnings and Cautions appear at appropriate sections throughout this manual. Read these carefully.

WARNING – Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.

CAUTION – Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury. It may also be used to alert against unsafe practices.

CAUTION – Indicates a situation that may result in equipment or property-damage-only accidents.

General

The purpose of this installation manual is to provide application, functional and calibration information for the Trane Retrofit package. Examples and charts are provided to enhance the understanding of this information.

Introduction

The DDC/VAV retrofit kit consists of the UCM control assembly, a Honeywell™ or Belimo™ actuator (both optional), and various accessories such as zone sensors, transformers, flow sensors, etc. This manual is intended to show how to apply, install and configure the DDC/VAV Retrofit kit. It is intended to provide information specific to the VAV retrofit. Refer to VAV-SVX01C-EN for complete DDC/VAV system wiring, installation and programming instructions.

Applications

The retrofit kit may be applied to pneumatic terminals by replacing the pneumatic actuator with an electric actuator or electrically controlled terminals by either using the existing electric actuator or by replacing it with one provided by Trane.

The kit may be used on existing shutoff, shutoff hot water reheat, shutoff with up to three stages of electric heat, and fan powered (both parallel and series) cooling only, hot water, and electric reheat units.

Note: Fan powered units have only two stages of reheat available.

Dual duct units may also be retrofitted using two sets of controllers. The kit has also been applied to constant volume reheat systems where the retrofit kit is used to control duct coils.

The kit has been tested on VAV terminals of several major manufacturers. It is mandatory for unit to have an external shaft to function properly with the direct coupled actuators offered.

Contents

This page about troubleshooting Trane air conditioning controls will discuss Trane's microelectronic controls and zone sensors.

This is the UCP board and zone sensor (wall thermostat) I've worked on in Trane package units in the 10 to 20 ton range.

According to their operation and troubleshooting manual 'MICRO-M-2D 18-HH60E2-4', these controls are used on units from 3 to 25 tons.

We'll start with the thermostat, which Trane calls a zone sensor.

It looks pretty much like a standard solid state thermostat, but you can't replace it with a standard thermostat, and the troubleshooting procedure will explain why.

Test 1 when troubleshooting Trane air conditioning controls:

Turn the unit off, open the zone sensor, and check for the following readings between terminals 1 and 2:

Test 2 when troubleshooting Trane air conditioning controls:

Look for 100 to 900 ohms between terminals 2 and 3, and 100 to 900 ohms between terminals 2 and 5.

Test 3.

Look for the following resistances between terminals 2 and 4.

As you can see, this zone sensor provides the controller with resistances, not open or closed switch contacts, which is why a normal thermostat won't work as a replacement.

These first three tests are as far as I've ever had to go when troubleshooting Trane air conditioning controls to find a failed zone sensor.

The booklet mentioned above has a lot more detailed information about troubleshooting procedures for Trane's zone sensors, and for the UCP board.

If you work on many of these units, this booklet will help a lot.

If you're troubleshooting Trane air conditioning controls and need to test the UCP board:

First, verify that the LED in the lower left corner of the board is on and steady.

Jump accross the two top terminals of the LTB.
These are the test terminals.

The LED will blink to indicate the unit is in test,

And this first test brings on the evaporator fan.

Jumper the test terminals again, and the Economizer will operate, if installed.

Jumper the test terminals again, and the first cooling stage will run.

Jumper the test terminals again, and the second cooling stage will run.

Jumper the test terminals again, and the first heat stage will operate.

Jumper again, and the second heat stage will operate if installed.

Jumper again, and the third heat stage will operate if installed.

Jumper again, and the defrost cycle will operate if installed.

Jumper again, and emergency heat will operate if installed.

Jumper again, and the unit will go into normal operation, and the LED will stay on steady.

If the board cycles through all installed stages normally, it is good.

I've seen Trane's boards go bad, but all except one were due to direct exposure to rain and moisture.

The most unusual problem I've seen regarding troubleshooting Trane air conditioning controls, was a low voltage control relay with a bad set of contacts on the UCP board.

The relay would energize and deliver control voltage to a voltage tester, but the contacts would drop the voltage if there was a load like a contactor in the circuit.

In an emergency, if you're troubleshooting Trane air conditioning controls on a unit with a failed zone sensor, need to get it running, and don't have one available for replacement, you can use the OAS thermistor.

Look under the control panel, on the right corner post.

There is a thermistor mounted there.

Cut the two splice caps in its leads, and isolate the cut wires in the control box by putting a wire nut on each one.

Slide the thermistor down and out of its grommet.

Install the thermistor in the return air flow, and wire it to terminals one and two on the LTB.
These are the second and third terminals down on the left row.

The unit will run in default mode, which I understand is set for 74° cooling, 71° heating.

I'm not sure about the heating setting.

The booklet isn't clear about it, and I've never had to do this during a heating season.

This is the warning note from the booklet:

This is for temporary operation only!

Economizer, condenser fan cycling, and evaporator defrost functions are disabled.

The evaporator will freeze during low ambient cooling.

Do You Know Some 'Inside Info' About Other Types of Trane Controls?

Do you have a lot of experience working on Trane heating and air conditioning controls?
Would you like to share your expertise, and write an article about some of the tips you've picked up from Trane service manuals and your practical hands-on experience?
We'd like to help you share your knowledge with other technicians and equipment owners world-wide, by including your article as a page on this site.

I hope the information on this page will save you some time and frustration when you're troubleshooting Trane air conditioning controls, and please, feel free to contact us with any specific HVAC questions you might have, including questions about air conditioning on Guam, or refrigeration on Guam.

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Trane Ucp Module Manual Diagram