Y594 (MULTISTAGE THERMOSTAT SUBBASE) PACKAGE
This control contains mercury in a sealed tube.
Do not place control in the trash at the end of its
Mounting and Wiring the Subbase
Disconnect power supply to prevent electrical shock or
equipment damage. All wiring must comply with local
electrical codes and ordinances. Follow equipment
manufacturer wiring instructions when available.
If this control is replacing a control that contains
mercury in a sealed tube, do not place your old
control in the trash.
Mount the subbase on a wall or horizontal outlet box. To
mount it on a vertical outlet box, order Honeywell part no.
96393A Cover Plate Assembly, which includes an
Contact your local waste management authority for
instructions regarding recycling and the proper
disposal of this control, or of an old control
containing mercury in a sealed tube.
adapter ring with two screws for vertical outlet box
mounting and a cover plate to cover marks on the wall.
To install subbase, proceed as follows:
Prepare a hole for the thermostat wires at the
chosen location. Run wires to location.
Pull about 6 in. (152 mm) of wire through the hole.
When Installing this Product…
Use 18 gauge, color-coded thermostat cable for
Read these instructions carefully. Failure to follow
them could damage the product or cause a hazard-
Check the ratings given in the instructions and on
the product to make sure the product is suitable for
Installer must be a trained, experienced service
After installation is complete, check out product
operation as provided in these instructions.
If mounting the subbase on a vertical outlet box,
install adapter ring with the two screws provided in
the assembly. See Fig. 1.
Pull wire through cover plate, if used, and subbase
wire opening. Secure the cover plate and subbase
with the two screws provided, but do not tighten
Level the subbase using a spirit level. See Fig. 2.
Tighten subbase mounting screws. The subbase
mounting slots provide for minor out-of-level
Disconnect power supply to prevent electrical
shock or equipment damage.
Run wires as close as possible to the sub-
base. To prevent interference with the
thermostat linkage, keep wire length to a
minimum. Push excess wire back into the
hole, and plug hole to prevent drafts from
affecting thermostat operation.
Do not overtighten thermostat captive
mounting screws because damage to
subbase threads can result.
Do not short across coil terminals on relay.
This may burn out the heat anticipator.
Never install more than one wire per terminal
unless factory-supplied jumper with spade
terminal is used.
An incorrectly leveled subbase will cause the
temperature control to deviate from setpoint
Connect the system wires to the subbase. See
Fig. 4-7. A letter is stamped near each terminal for
identification. The terminal barrier permits straight or
conventional wraparound wiring connections. See
Fig. 3. Either method is acceptable. Run wires as
close as possible to the subbase, keeping wire
length to a minimum. Push excess wire back into
hole. Plug hole to prevent drafts.
Thermostats are calibrated at the factory by using
Mounting the Thermostat
Remove the thermostat cover by pulling the bottom
edge of the cover away from the base until it snaps
free of the retaining posts.
subbases mounted at true level. Inaccurate sub-
base leveling will cause thermostat control
NOTE: The cover is hinged at the top and must be
removed by pulling out at the bottom.
Install the thermostat about 5 ft (1.5m) above the floor in
an area with good air circulation at average room
Carefully remove and discard the polystyrene
packing insert that protects the mercury switches
Turn the thermostat over and locate the spring
fingers that engage the subbase contacts. Make
sure the spring fingers are NOT bent flat, preventing
proper electrical contact with the subbase.
Set adjustable heat anticipator indicators, if
provided, as described in Setting the Heat
Do not mount the thermostat where it may be affected by:
drafts, or dead spots (no air movement) behind doors,
in corners, and above or below shelves.
hot or cold air from ducts.
radiant heat from the sun, lights, or appliances.
concealed pipes and chimneys.
unheated or uncooled areas such as an outside wall
behind the thermostat.