The thermostat is accurately calibrated
before leaving the factory and no further
calibration should be necessary. If the
thermostat appears to be out of calibration
or for any reason fails to function properly,
a qualified serviceperson should proceed as
follows:
1. The anticipator’s heat may adversely affect
thermostat recalibration. To prevent this,
disconnect electrical power power to the
thermostat at the furnace, main fuse, or
breaker box.
2. Move temperature adjustment lever to a
setting about 5° above room temperature.
3. Remove thermostat cover. Slip 7/32” wrench
onto hex nut beneath bimetal. While
holding temperature adjustment lever
stationary, turn hex nut clockwise until
mercury shifts to the right end of the tube
(fig. 7).
4. Move temperature adjustment lever to
lowest setting.
5. Replace thermostat cover. Wait 10 min.
for bimetal temperature to stabilize. Do
not stand near the thermostat during this
period, as your breath and body heat will
affect bimetal temperature.
6. Move temperature adjustment lever to
correspond to actual room temperature.
Then remove thermostat cover.
7. Slip 7/32” wrench onto hex nut. While
holding temperature adjustment lever
stationary, turn hex nut counter-clockwise
until mercury just barely shifts to the left
end of the tube.
8. Replace thermostat cover and set
temperature adjustment lever to desired
temperature. Turn on electrical power to
system.
Bimetal
Temperature
adjustment
lever
7/32” Calibration
wrench
FIG. 6. CALIBRATING THERMOSTAT
Some heating installations require longer or
shorter “ON”, “OFF” periods to maintain even
temperatures. For average conditions, set the
heat anticipator indicator to match the current
rating of the primary heating control. Move
indicator approximately 1/2 division in direction
indicated by the arrows on the thermostat for
longer “ON” cycles, or move lever in opposite
direction for shorter “ON” cycles. Allow at
least 24 hours to determine if setting provides
satisfactory operation before making any
further adjustments.
CLIMATE
TECHNOLOGY
CORPORATION
M E R C U R Y B U L B
MECHANICAL
THERMOSTAT
CTC thermostats regulate 24 to 30 VAC single-stage heating-cooling systems. See the chart below
for specific models and applications.
THERMOSTAT MODELS AND APPLICATIONS
To avoid electrical shock or equipment damage, make
sure power is disconnected before installation.
WARNING!
This product contains mercury
in a sealed tube.
DO NOT
place this
control in the trash at the end of its
useful life.
If this product is replacing a control that
contains mercury,
DO NOT
place the old
product in the trash.
Contact your local waste management
authority for instructions regarding recycling
and the proper disposal of this product, or of
and for any old control containing mercury in
a sealed tube.
Disposal Information
When installing this product:
• Read these instructions thoroughly. Failure
to follow them could damage the product
or produce an unsafe condition.
• Check the ratings in these instructions and
on the product to make sure the product is
compatible with your application.
• Installation must be performed by a
trained, experienced service technician.
• Upon completion of the installation, verify
the correct operation of the product as
detailed in these instructions.
INSTALLATION
The thermostat should be located in an
area with good air circulation at average
temperature. It should be on an inside wall.
DO NOT place the thermostat where it can
be affected by:
– drafts or dead spots behind doors or in
corners.
– hot or cold air from ducts.
– radiant heat from the sun, fireplaces, or
appliances.
– unheated (uncooled) areas behind the
thermostat, such as outside walls.
This thermostat is a precision instrument and
was carefully adjusted at the factory.
Handle it
carefully.
LOCATION
ELECTRICAL DATA
Switch Rating:
24VAC (30 VAC max.)
Heating - 0.2 to 1.2 amps
Cooling - 0-1.5 amps
Switch Action:
Sealed mercury switch
Anticipator rating:
Heating - Adjustable from 0.2 to 1.2 Amps
Cooling - Fixed 24 VAC
THERMAL DATA
Temperature Range:
50ºF - 90ºF (10ºC - 32ºC)
APPLICATIONS
This thermostat is designed for use with:
• Standard heating and cooling systems
• Electric heating and cooling systems
• Single stage heat pump systems
• Two-transformer systems
• Electronic air cleaners
• Humidifiers
• Zone Dampers
This thermostat
cannot be used
with:
• Millivolt systems
• Multi-stage applications
CALIBRATION
HEAT ANTICIPATION ADJUSTMENT
SPECIFICATIONS
SERVICE INSTRUCTIONS
FIG. 7. ANTICIPATOR ADJUSTMENT
Arrow points to the
matched current rating
of the primary control.
Move this lever
to adjust heat
anticipator.
41630-01 4/22/2003
Tools needed for installation:
• Slotted Screwdriver
• Electric Drill and 3/16” Bit
• Hammer
• Level
pg. 4
Climate Technology Corp.
2500 Frisco Avenue
Memphis, TN 38114
A Hunter Fan Company
