KING GPT 3 User Manual

We manage heat

®

®

Model GPT–3

Freeze Protection Thermostat

Part Number 19425

Installation and Operation Manual

Environmental Technology, Inc.

1850 N Sheridan Street
South Bend, Indiana 46628
[phone] or [phone]
FAX [phone] or [phone]
http://www.networketi.com/

DISCLAIMER

Environmental Technology, Inc. makes no representations or warranties, either expressed or implied,

with respect to the contents of this publication or the products that it describes, and specifically

disclaims any implied warranties of merchantability or fitness for any particular purpose.

Environmental Technology, Inc. reserves the right to revise this publication and to make changes and

improvements to the products described in this publication without the obligation of Environmental

Technology, Inc. to notify any person or organization of such revisions, changes or improvements.

Copyright © 2005 Environmental Technology, Inc. All rights reserved. No part of this manual may be

reproduced or translated in any form or by any means, electronic or mechanical including photocopying

and recording, for any purpose without the express written consent of Environmental Technology, Inc.

The ETI logo, We Manage Heat, Tracon and GPT are reg is tered trademarks of En vi ron men tal

Technology, Inc.

Printed in USA

PN20656 rev 6/2006

Table of Contents

Safety 7

Contacting Environmental Technology 7

General 7

Introduction 7

Specifi cations 9

Operation 10

Normal 10

Abnormal 10

Installation 10

First 10

Next 10

Location 11

Supply and Heater Connections 11

Sensor and Alarm Relay Connections 12

General 12

Temperature Sensors 12

Alarm Relay Contacts 14

Setup 14

Factory Settings 14

Custom Settings 15

General 15

GFEP 15

Mode 15

Current 16

Constant Wattage Heater Mode 16

Maintenance 17

General 17

Troubleshooting 17

Returns 17

Page 3 of 21

Page 4 of 21

Index of Figures

Figure 1. GPT–3 dimensional drawing 8

Figure 2. GPT–3 wiring diagram 11

Figure 3. Control and monitor sensor connections for self-limiting heaters 12

Figure 4. Control sensor connection for constant wattage heaters 13

Figure 5. Alarm relay connections 13

Figure 6. DIP switch detail 14

Figure 7. Removing electronic assembly from housing 15

Appendix A. GPT–3 dimensional drawing. 18

Appendix B. GPT–3 wiring diagram. 19

Appendix C. Control and monitor sensor connections for self-limiting heaters. 20

Appendix D. Control and monitor sensor connections for constant wattage heaters 21

Page 5 of 21

Page 6 of 21

Safety

Make all electrical connections in compliance with the National Electric Code (NFPA 70)

and local electrical code. If you have questions concerning the installation or application, contact

Customer Service.

Contacting Environmental Technology

For assistance, contact Customer Service. Office hours are 8:00 AM until 5:00 PM EST

(UTC minus five hours).

Voice: [phone] (USA and Canada) or [phone] (elsewhere)

Fax: [phone] (USA and Canada) or [phone] (elsewhere)

E-mail: [e-mail]

Mail: Environmental Technology, Inc.

1850 North Sheridan Street

South Bend, IN 46628

General

Introduction

The GPT–3 Freeze Protection Thermostat has a calibrated adjustment range of 41° to 77°F

(5° to 25°C) with a control band of 2°F (1°C). Heaters operate at ambient temperatures below the

set temperature.

The GPT–3 combines temperature control using either constant wattage or self-limiting

heaters with GFEP (ground fault equipment protection) and advanced monitoring features. For

example, although the GFEP is factory set to trip at 30 mA, this threshhold can be set to 60,

90 or 120 mA to cure nuisance tripping problems. Keeping wet fire sprinklers from freezing is

considered to be a higher priority than interrupting heater power in the event of a ground fault

condition. The GPT–3 accommodates this requirement by allowing the GFEP to be set only to

alarm while the ground fault persists.

Other features include continuous heater monitoring with separate modes for constant

wattage and self-limiting heaters. A trickle current verifies heater continuity of both heater

types when there is no call for heat. The current flow through constant wattage heaters verifies

continuity during operation. Self-limiting heaters employ an independent temperature monitor

sensor (included) to measure the hot-end temperature. Depending upon how long it takes the

cable to reach its operating temperature such that the monitor sensor is less than 5°F (3°C) below

Page 7 of 21

the control sensor temperature, the GPT–3 may momentarily declare a cold heater.

The GPT–3 automatically executes a self-test every 24 hours. First, heaters are de-

energized. Then, the GFEP verifies its own operation. Finally, it checks the heaters for ground

fault under operating conditions. This entire process takes about two seconds.

Other features include verifying the integrity of both the control and monitor temperature

sensors and checking the contactor for open or shorted contacts. A control temperature sensor

failure also inhibits contactor operation in addition to asserting an alarm condition.

The GPT–3 automatically accommodates 120, 208, 240 and 277 supply voltages. Since

the heaters and the GPT–3 operate from the same supply voltage, the safety hazard created by

multiple points of disconnect is eliminated. The heater control contactor is rated for up to 30

amps.

The GPT–3 provides a reverse acting isolated Class 2 alarm relay contact SPDT rated at one

amp. Reverse action makes absence of supply voltage an alarmed condition.

Although the GPT–3 housing is NEMA 3R rated for indoor or outdoor service, a protected

location is recommended. The operating temperature range is −40° to 136° F (−40° to 58°C).

Padlocking the transparent front cover can prevent tampering without interfering with the view

of the status indicators.

3

/4" (21mm)

Conduit Entry

Grounding Lug

3

/4" (21mm)

Conduit Entry

Low Voltage

Compartment

High Voltage

Compartment

(102mm)

C

L

2"

(51mm)

4"

1

/8"

2

(54mm)

J1

C

L

1

/2"

11

(292mm)

12"

(305mm)

TRACON

GFEP

FAULT

HEATER

FAULT

GFEP

®

–

GPT

RESET

50

10

TEST

5

41

Temperature

®

http://www.networketi.com
e-mail: [e-mail]

3

®

SUPPLY

HEATER

59
15

25
°C
°F

We Manage Heat

68

20

77

®

Figure 1. GPT–3 dimensional drawing

51/2"

(140mm)

1

/8"

9

(232mm)

9

/16"

6

(167mm)

C

L

25/16"

(59mm)

Page 8 of 21

Specifi cations

Control

Range: 41° to 77°F (5° to 25°C)

Dead band: 2°F (1°C)

Electrical

Supply: 120, 208, 240 or 277 volts auto-selected

Heater load: 30 amps maximum

Alarm relay: Isolated SPDT 1 amp Class 2 contact

Indicators

Supply (red) Power applied

Heater (yellow) Call for heat

GFEP (red) Ground fault occurring or has occurred

FAULT (red) Contactor failure

Temperature sensor failure

Power-on self-check failure

GFEP

Settings: 30 mA default, 60, 90, 120 mA selectable

Reset: Manual default, automatic selectable

Auto-test: Every 24 hours

Heater monitoring

Choices: Self-limiting default, constant wattage selectable

Alarm relay: No power

Heater failure

Contactor failure

Ground fault or GFEP circuit failure

Temperature sensor failure

Temperature limits

Operating: −40° to 136° F (−40° to 58° C)

Storage: −67° to 167° F (−55° to 75° C)

Page 9 of 21

Operation

Normal

The GPT–3 requires little or no attention after installation. Although changing the

temperature setting can improve heating system performance, this is seldom necessary. Minimum

energy use occurs when the the temperature is set to the minimum value providing the desired

heating performance.

Normal operation occurs when neither the Fault nor the GFEP indicators operate and the

Alarm relay is off. Otherwise, operation is abnormal.

Abnormal

With one exception, operation of either the Alarm relay or Fault indicator or both means that

a failure has occurred that requires a qualified electrician to correct. The exception is momentary

indication of a self-limiting heater failure as is shown by blinking the Heater indicator when

the GPT–3 is used with self-limiting cable. The GPT–3 detects a self-limiting heater failure by

measuring its temperature at the far end of the cable. Depending upon how long it takes the cable

to reach its operating temperature such that the monitor sensor is less than 5°F (3°C) below the

control sensor temperature, the GPT–3 may momentarily declare a cold heater.

Many indicators display additional information concerning equipment failures through

flashing. Check the Troubleshooting section for additional information since service by qualified

personnel is required.

Installation

First

Inspect the package and its contents for damage. In the event of damage, immediately

contact Environmental Technology, Inc. Customer Service.

Next

Check the contents of the package against the pro forma Packing List shown below. If

discrepancies are found, contact ETI Customer Service before starting the installation.

Pro Forma Packing List

Order Number Quantity Description

19425 1 GPT–3 Freeze Protection Thermostat

19272 2 Temperature Sensor
20656 1 GPT–3 Installation and Operation Manual
18703 4 Wire Nuts, Red

Page 10 of 21

Location

The GPT–3 is suitable for indoor or outdoor mounting on a vertical surface. Although the

NEMA 3R rated housing is strong and durable, choose a protected location for an extra safety

margin. Always consider the possibilities of tampering and vandalism when choosing a location.

Keep the GPT–3 and the heat cable as close together as is practical to minimize installation

costs. There is a 2,000’ (610m) limit on temperature sensor extension wiring.

Figure 1 shows mechanical dimensions of the GPT–3. Note the location of the

compartment provided for low voltage Class 2 connections.

Supply and Heater Connections

The GPT–3 operates from 120, 208, 240 or 277 volts which it automatically selects. The

heaters and GPT–3 operate from the same supply voltage.

The definite purpose DPST heater control contactor is rated for up to 30 AMP loads at 277

volts or less.

Make the supply voltage and heater connections in the compartment provided for this

purpose. See Figure 1.

Use only copper wire for supply, heater and safety ground connections. Select a minimum

Equipment

Safety
Ground

Heater Shield

Ground

J1

From 120, 208,
240, or 277 VAC
Supply

GPT

TRACON

GFEP

FAULT

HEATER

FAULT

RESET

GFEP

TEST

®

–

3

®

59
15

50

10

5

41

°C
°F

Temperature

®

We Manage Heat

http://www.networketi.com
e-mail: [e-mail]

SUPPLY

HEATER

25

68

20

77

®

To Heater

30 Amp Load Max

.

Figure 2. GPT–3 wiring diagram

Line/L1
Neutral/L2
Ground

Page 11 of 21

wire size of 10 AWG with, minimum, 300 volt insulation rated for at least 75ºC.

Figure 2 shows a pictorial wiring diagram of the heater and supply voltage connections. Use

appropriately rated wire nuts or bomb splices for all heater and supply connections. Connect the

equipment safety ground and heater shield ground to the lug provided for this purpose.

Sensor and Alarm Relay Connections

General

The two temperature sensors are connected to the terminal block in the low voltage

compartment along with the connections to the reverse acting isolated SPDT alarm relay. Use

#18 AWG copper wire with insulation rated for 300 volt service for all Class 2 connections

unless otherwise noted. Using jacketed extension wiring, although convenient, is not necessary.

Using metallic conduit for extension wires is recommended. Never route Class 2 circuits in

the conduit used for supply and heater voltage circuits.

Temperature Sensors

Two identical temperature sensors are supplied with the GPT–3. Each is supplied with

20' (6m) of extension wire. For distances of up to 500' (152m), use #18 AWG copper wire and

#12AWG for up to 2,000' (610m). Temperature sensor connections are non-polar.

Systems using self-limiting heaters require two temperature sensors. Figure 3 shows

Monitor Temperature Sensor Control Temperature Sensor

Low Voltage

Compartment

J1

TRACON

GFEP
FAULT

HEATER

FAULT

GFEP

®

–

GPT

3

RESET

50

10

TEST

5

41

Temperature

®

http://www.networketi.com
e-mail: [e-mail]

®

SUPPLY

HEATER

59
15

20

25

77

°C
°F

We Manage Heat

68

®

Page 12 of 21

Figure 3. Control and monitor sensor connections for self-limiting heaters

J1

®

3

N

®

G

FAULT
SU

G

RES

ST

20

15

68

9
25

10

5

50
1

C

We Manage Heat

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http

m

®

A
A
A

Low Voltage

Compartment

HEATER

Control Temperature Sensor

Figure 4. Control sensor connection for constant wattage heaters

GPT

TRACON

GFEP

FAULT

FAULT

RESET

GFEP

TEST

®

–

3

®

SUPPLY

HEATER

59
15

50

68

20

10

5

25

77

41

°C
°F

Temperature

®

We Manage Heat

http://www.networketi.com
e-mail: [e-mail]

®

J1

GPT

TRACO

FEP

PPLY

FAULT

5

ET

FEP

TE

77

4

Temperature

://www.networketi.co

e-mail: [e-mail]

J1

larm Relay ----------­larm Relay --

Normally Closed

larm Relay ----

Common

Normally Open

Sensor Connections

Ground

Figure 5. Alarm relay connections

Page 13 of 21

connection of the two sensors. The GPT–3 comes factory set for self-limiting cable.

Systems using constant-wattage heaters require only one sensor as is shown in Figure 4.

Upon completion of the installation, dispose of the unused sensor.

Alarm Relay Contacts

Figure 5 shows the alarm relay connections. The relay contacts are rated for one amp in

NEC Class 2 service. Contact Customer Service if higher voltage operation is required.

Setup

Factory Settings

The GPT–3 comes set for the most common systems. This includes:

• Self-limiting cable

• GFEP set at 30 mA

• GFEP set for manual reset

The factory DIP switch settings follow:

FACTORY SETTINGS

Pole 1 2 3 4 5 6

Setting Off Off Off Off --- ---

Page 14 of 21

O

N

OFF

Figure 6. DIP switch detail

ONOFF

1

2 3 4 5 6

1

2 3 4 5 6

J1

®

–

GPT

TRACON

3

®

GFEP

FAULT

HEATER

FAULT

GFEP

RESET

TEST

SUPPLY

HEATER

59
15

50

http://www.networketi.com
e-mail: [e-mail]

10

5

41

°C
°F

Temperature

®

We Manage Heat

68

20

25

77

®

Figure 7. Removing electronic assembly from housing

Custom Settings

General

The performance of the GPT–3 can be adjusted to match the needs of the application

using the DIP switch as shown in Figure 6. Accessing this switch usually requires removing

the electronic assembly from its housing. Figure 7 shows the screws that need to be removed to

access the DIP switch.

Make any DIP switch changes before making the supply voltage and heater connections.

Otherwise, it will probably be necessary to break and re-make these connections.

DIP switch poles that do not require change are labeled ‘NC’. Spare switch poles are

labeled ‘---’.

GFEP

Mode

Fire protection sprinkler and certain other critical applications consider GFEP secondary in

importance to freeze protection. The GPT–3 accommodates these applications by warning of a

ground fault condition while it exists. Heaters operate independent of the ground fault condition.

Automatic GFEP Reset Setting

Pole 1 2 3 4 5 6

Setting On NC NC NC --- ----

Page 15 of 21

Current

The GFEP current setting can be increased from its factory set 30 mA value to 120 mA in

30 mA steps. The higher current settings serve the special purpose of eliminating spurious GFEP

tripping. Accessing this function was made intentionally difficult to prevent its casual use. The

DIP switch settings follow:

60 mA GFEP Setting

Pole 1 2 3 4 5 6

Setting NC NC On Off --- ---

90 mA GFEP Setting

Pole 1 2 3 4 5 6

Setting NC NC Off On --- ---

120 mA GFEP Setting

Pole 1 2 3 4 5 6

Setting NC NC On On --- ---

Constant Wattage Heater Mode

The GPT–3 provides a special operating mode for checking the continuity of constant

wattage heaters. The DIP switch setting is shown below:

Constant Wattage Heater Setting

Pole 1 2 3 4 5 6

Setting NC On NC NC --- ---

Page 16 of 21

Maintenance

General

The GPT–3 does not require routine maintenance. It contains no field replaceable

components.

Troubleshooting

The GPT–3 provides extensive fault diagnosis capability for the purpose of quickly

identifying and correcting system problems. Front panel indicators perform multiple functions

so as to provide the greatest amount of information. With one exception one, or more, indicators

flashing in repetitive patterns mean that a fault requiring a qualified technician for correction has

occurred.

The exception is operation of the HEATER FAULT indicator in a 50% on, 50% off pattern

when using self-limiting cable. This can occur when heaters first operate due to the time delay

between the application of power and attaining thermal equilibrium.

Detailed troubleshooting instruction can be obtained from either Customer Service or the

Environmental Technology, Inc. web site at http://www.networketi.com.

Returns

Contact Customer Service to obtain a Return Authorization before shipping anything to

Environmental Technology, Inc. Otherwise, the shipment may be refused.

Page 17 of 21

Appendix A. GPT–3 dimensional drawing.

"

16

/

5

2

(59mm)

"

2

/

1

5

"

8

/

1

9

(140mm)

(232mm)

L

C

"

16

/

9

6

(167mm)

L

C

2"

(51mm)

" (21mm)

4

/

3

Conduit Entry

J1

®

3

–

®

GPT

Low Voltage

SUPPLY

TRACON

GFEP

FAULT

Compartment

®

77

20

25

HEATER

FAULT

HEATER

°F

156859

°C

We Manage Heat

5

Temperature

®

41

10

50

RESET

TEST

GFEP

http://www.networketi.com

e-mail: [e-mail]

"

8

/

1

2

(54mm)

"

L

C

2

/

1

11

12"

(292mm)

(305mm)

4"

(102mm)

High Voltage

Compartment

" (21mm)

4

/

3

Conduit Entry

Page 18 of 21

Grounding Lug

Appendix B. GPT–3 wiring diagram.

®

77

20

25

°F

156859

10

50

RESET

GFEP

5

TEST

°C

41

Temperature

We Manage Heat

®

http://www.networketi.com

e-mail: [e-mail]

J1

®

3

–

®

GPT

TRACON

SUPPLY

GFEP

HEATER

FAULT

FAULT

HEATER

From 120, 208,

240, or 277 VAC

Supply

Neutral/L2

Ground

Line/L1

.

To Heater

Safety

Ground

30 Amp Load Max

Equipment

Ground

Heater Shield

Page 19 of 21

Appendix C. Control and monitor sensor connections for self-

limiting heaters.

®

77

20

25

°F

156859

°C

5

10

50

TEST

RESET

GFEP

FAULT

We Manage Heat

Temperature

®

41

http://www.networketi.com

e-mail: [e-mail]

®

J1

®

3

–

GPT

TRACON

Low Voltage

Compartment

GFEP

SUPPLY

HEATER

FAULT

HEATER

Page 20 of 21

Monitor Temperature Sensor Control Temperature Sensor

Appendix D. Control and monitor sensor connections for

constant wattage heaters

®

77

20

25

°F

156859

°C

Temperature

We Manage Heat

®

http://www.networketi.com

e-mail: [e-mail]

10

50

RESET

GFEP

TEST

5

41

J1

®

3

–

®

GPT

TRACON

GFEP

SUPPLY

HEATER

FAULT

FAULT

HEATER

Low Voltage

Compartment

Control Temperature Sensor

Page 21 of 21