Chromalox PK477 User Manual
PK477
161-506096-001
JUNE, 1995
4WT
Installation Instructions
(Supersedes PK477)
Type WT Room Thermostat
© 2010 Chromalox, Inc.
GENERAL
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.
WARNING: 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 recommendations.
WARNING: 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 3
1
/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 con-
trolled. 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.
Temp Maximum Rating
Range Contacts
Model
(°F) 128V AC 208V AC 240V AC 277V AC Pilot Duty
125V AC
WT-121 45-75 SPST 22 amps 22 amps 22 amps 18 amps (use with
or 2640 or 4575 or 5280 or 5000 AC
WT-122 45-75 DPST total watts total watts total watts total watts contactor)
Specifications — Table A
4.72"
(110)
Fr
o
nt Vi
ew
2.14"
(54)
Side View
2.86"
(73)
1347 HEIL QUAKER BLVD., LAVERGNE, TN 37086
Phone: (615) 793-3900 www.chromalox.com
INSTALLATION
WIRING
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 con-
necting 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 pro-
vided. Take care not to push or damage the bimetal sensing element during installation.
6. Replace the thermostat front cover and knob.
WARNING: Any knob temperature setting below
50°F may result in freezing.
WARNING: Hazard of Electric Shock. Disconnect all
power before wiring or servicing this control.
Electric wiring to heater must be installed in accordance with
National Electrical Code and with local codes.
WARNING: Use copper conductors only.
Connect wires according to wiring diagrams (Figures 1 and 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 rating, a
contactor must be used.
Figure 1:
Figure 2:
Note:
1. Connect anticipator lead (white) in parallel with heater.
2. Thermostat performance will be degraded if anticipator connection 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.
Limited Warranty:
Please refer to the Chromalox limited warranty applicable to this product at
http://www.chromalox.com/customer-service/policies/termsofsale.aspx.
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