Chromalox WT-121 User manual

Installation Instructions
WT Room Thermostat
PK477-1
161-506096-001
November, 2016

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Note: Type WT thermostats are designed for temperature
control service only. Because they do not fail safe, they
should not be used for temperature limiting duty.
Users should install adequate back-up controls and
safety devices with their electric heating equipment.
Where the consequences of failure may be severe,
back-up controls are essential. Although the safety
of the installation is the responsibility of the user,
Chromalox will be glad to make equipment recom-
mendations.
Not for use in hazardous environments as described
in the National Electrical Code. Failure to comply
can result in explosion or fire.
Thermostat Location
1. Mount in any standard electrical outlet box. Use of extra
deep box (3” x 2” x 31/2”) makes for easier wiring.
2. Locate outlet box about 5’ above floor on inside wall.
3. Box location should be representative of the area to be
controlled. Avoid locations that are subject to drafts or
false external heat (such as solar radiation, direct heat
from heaters, etc.). Insure that the wall selected is capped
to prevent drafts within the wall.
General
4.72"
(110)
Fr
o
nt Vi
ew
2.14"
(54)
Side View
2.86"
(73)
Model
Temp.
Range
(˚F) Contacts
Maximum Rating
24V AC 120V AC 208V AC 240V AC 277V AC Pilot Duty
WT-121 45-75 SPST 22 amps or
528 total
watts
22 amps or
2640 total
watts
22 amps or
4575 total
watts
22 amps or
5280 total
watts
18 amps or
5000 total
watts
125V AC (use with
AC contactor)
WT-122 45-75 DPST
1. Cut lead wires protruding from outlet box approximately
4” from wall surface and strip end insulation 1/2”.
2. Always test the heater circuit for electrical shorts before
connecting the thermostat.
3. Remove thermostat knob and front cover.
4. Using wire-nuts or other local code approved devices,
connect load and line wires to appropriate color coded
thermostat wires. (See wiring diagrams below.)
5. Mount the thermostat to the outlet box using the screws
provided. Take care not to push or damage the bimetal
sensing element during installation.
6. Replace the thermostat front cover and knob.
Any knob temperature setting below 50°F may re-
sult in freezing.
Installation

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Hazard of Electric Shock. Disconnect all power be-
fore wiring or servicing this control.
Electric wiring to heater must be installed in accordance with
National Electrical Code and with local codes.
Use copper conductors only.
Connect wires according to wiring diagrams (Figures 1 & 2).
Note: Electrical connections should be made with generous
loops of wire — approximately 6” per lead.
Note: If load amperage or voltage rating exceeds switch rat-
ing, a contactor must be used.
Wiring
Figure 1 Figure 2
Note:
1. Connect anticipator lead (white) in parallel with heater.
2. Thermostat performance will be degraded if anticipator con-
nection is omitted.
Note:
1. Suitable for control of one heating load only.
2. No separate connection required for heat anticipation.
3. Temperature control switch is located on right hand side when
thermostat is viewed from the rear.

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Limited Warranty:
Please refer to the Chromalox limited warranty applicable to this product at
http://www.chromalox.com/customer-service/policies/termsofsale.aspx.
© 2014 Chromalox, Inc.
Chromalox, Inc.
1347 Heil Quaker Boulevard
Lavergne, TN 37086
[phone]
www.chromalox.com