Environmental Technology FWT-3H Installation And Operating Instructions Manual

We Manage Heat®

FWT®- 3H Hydronic Thermostat

(Order Number 19090)

Installation And Operating Instructions

Environmental Technology, Inc.

1850 N Sheridan Street

South Bend, Indiana 46628

[phone]

FAX [phone]

9091 # ITE

4 fo 1 egaP2 rev A

May 2008

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.

Before disposing of the packing material, verify the inclusion of items in the packing list. Immediately notify CUSTOMER

SERVICE of any discrepancy or shipping damage.

Packing List

Quantity

1 19092 Installation and Operation Instructions
1 19088 FWT-3H Electronic Assembly
2 18581 Wall Plate Screw, White
1 19272 Temperature Sensor/Extension Cable

Part Number Description

Installation

Mounting

The FWT-3H Electronic Assembly mounts in a single-gang switch box (customer supplied). Choose a mounting location that
is convenient and reasonably close to the temperature sensor. The Temperature Sensor comes with 20 feet (6.1m) of jacketed extension
cable. The cable length can be shortened if the entire 20 feet is not needed for the chosen mounting location. Shortening the cable will
not affect performance of the FWT-3H. Locate the temperature sensor within the heated space as shown in Figure 1. Do not
temperature sensor or extension cable to cross over or come in contact with any heating source such as a hydronic tubing run.

Though it is not required, it is highly recommended that the temperature sensor/extension cable be housed in conduit as shown.
This will make replacing the temperature sensor much easier in the unlikely event it ever needs to be replaced. The entire length of the
extension cable need not be housed in conduit; only the length traveling through the floor substrate and a short vertical section behind an
adjacent wall (generally where the extension cable rises up out of the floor substrate). Use thin wall conduit with a minimum diameter of
½". Be sure the temperature sensor can pass through the conduit unobstructed when the extension cable is fed through. Cap the end of
the conduit in the heated space prior to installation of the floor substrate. This avoids clogging the conduit and wedging the temperature
sensor against the conduit wall. Also make sure that the temperature sensor reaches the cap at the end of the conduit.

allow the

Wiring

Figure 2 shows the relay, Temperature Sensor and power source connections to the terminal block on the back of the FWT-3H
Electronic Assembly. A label on the terminal block identifies these connections. The relay is a normally open isolated contact rated at
3 Amps resistive, or 1 Amp inductive. The FWT-3H requires an NEC Class 2, 24 volt AC power source (customer supplied), rated at
5VA or higher to operate. Many hydronic systems use 24 volts AC, which is suitable for powering the FWT-3H. If power cannot be
derived from the hydronic system, a separate 24 volt AC Class 2 transformer must be used. If the controlled device (pump contactor, zone
valve, boiler control, etc.) is being supplied from the same power source supplying the FWT-3H, make sure the source has sufficient
VA capacity to supply both loads. When making the relay and power source connections, use #18 AWG stranded wires if the wire lengths
needed are less than 50 feet. For lengths more than 50 feet, but less than 150 feet, use #16 AWG stranded wires. For lengths greater than
150 feet, contact CUSTOMER SERVICE. Connect the temperature sensor extension cable leads into to the terminal block as shown in
Figure 2. Reversing these leads does not interfere with operation of the FWT-3H.

4 fo 2 egaP2 rev A9091 # ITE

May 2008

To controlled device
(contactor, zone valve, etc.)

FWT–3H

temperature sensor /

extension cable

(Customer Supplied)

Conduit for

To 24VAC Class 2
Power supply

(Customer Supplied)

Single-Gang
Switch Box

(Customer Supplied)

Extension Cable

Temperature

Sensor

Cap

Conduit

Extension Cable

Cap

Hydronic Tubing Run

3 ft. (approx.)

Figure 1

FWT-3H Electronic Assembly/Temperature Sensor Mounting

FWT-3H Thermostat

(rear view)

Jacketed Extension Cable

Temperature Sensor

RELAY SENS OR

9091 # ITE

24 VAC

SV

Solenoid valve, pump contactor,

or boiler control

Figure 2

FWT-3H Wiring Diagram

24 VAC

power source

4 fo 3 egaP2 rev A

May 2008

Operation

The green POWER indicator operates to show that power is available.

The yellow HEAT indicator operates and the relay contact closes during heating.

The knob sets the operating temperature. Clockwise rotation increases the temperature.

Full counterclockwise rotation puts the system or zone in IDLE mode which prevents heating. This feature saves energy by not heating
unoccupied areas. The HEAT indicator blinks slowly when the IDLE mode has been selected.

Troubleshooting

Our experience shows that installation errors cause the majority of problems. Frequently encountered problems include wiring errors.
Simple electrical tests and visual inspections usually identify these problems.

Neither indicator operates and there is no heat.

Power is probably not available - check the power source connection at the terminal block. If the problem persists with 24 volts

AC available and power wires are properly connected, the FWT-3H Electronic Assembly is probably defective. Contact

CUSTOMER SERVICE.

Both indicators operate continuously and there is no heat.

There may be an open circuit in the wiring between the RELAY connection and the controlled device (pump contactor, zone

valve, boiler control, etc.). If this wiring is ok and the problem persists, a malfunction in the controlled device or the hydronic

heating system is the likely source of the problem.

The yellow HEAT indicator blinks rapidly and there is no heat.

The FWT-3H is detecting an open circuit in the Temperature Sensor connection. When this happens, the relay remains de-

energized (contacts open), regardless of the temperature setting. Make sure the wires in the Temperature Sensor extension cable

are properly connected to the terminal block. If the wires are properly connected and the problem persists, the Temperature Sensor

extension cable has probably been severed at some location along its length. A defective Temperature Sensor is possible, though

unlikely.

There is continuous heat and the yellow HEAT indicator is off.

There may be a short circuit in the wiring between the RELAY connection and the controlled device. A short in this wiring can

emulate a continuously closed relay contact without illuminating the HEAT indicator. If the wiring is ok and the problem persists,

a malfunction in the controlled device or the hydronic heating system is the likely source of the problem.

QUESTIONS AND COMMENTS

For technical help, questions or comments concerning this product or any of Environmental Technology, Inc. products contact
the Customer Service Department between 8:00am and 5:00pm EST at:

Voice: 800.234.4239 (USA and Canada) Fax: [phone] (USA and Canada)

)erehwesle( 2512.332.475)erehwesle( 2021.332.475

E-mail: [e-mail]

®

ENVIRONMENTAL TECHNOLOGY, INC.

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

The ETI Logo, We Manage Heat and FWT are registered trademarks of Environmental Technology, Inc.

Copyright ©2008 Environmental Technology, Inc. All rights reserved.

9091 # ITE

4 fo 4 egaP2 rev A

May 2008