Doit 474053 Low Voltage Thermostat Installation Guide

INSTALLATION & OPERATION GUIDE
Model No. 474053
Low Voltage ThermostatOperator: Save this booklet for future use!

About Your New Thermostat . . .
You have selected the 474053 low voltage heating/cooling thermostat. The sensitive spiral bimetal temperature sensor is combined with an adjustable heating anticipator and a fixed cooling anticipator to provide maximum comfort. Your new thermostat is easy to install and operate. You only need one regular screwdriver and a level — all other hardware is included.
Please read this manual thoroughly before installing or operating your thermostat.

PRECAUTIONS

NOTE
If in doubt whether your wiring is millivolt, line, or low voltage, have the wiring inspected by a qualified heating and air contractor, electrician, or someone familiar with basic electricity and wiring.
Do not exceed the specification ratings.
All wiring must conform to local and national electrical codes and ordinances.
This control is a precision instrument, and should be handled carefully. Rough handling or distorting components could cause the control to malfunction.
CAUTION
To prevent electrical shock and/or equipment damage, disconnect electrical power to the system, at main fuse or circuit breaker box, until installation is complete.
Do not short out terminals on gas valve or primary control to test. Short or incorrect wiring will burn out heat anticipator and could cause personal injury and/or property damage.
WARNING
Do not use on circuits exceeding 30 volts. Higher voltage will damage the control and could cause shock or fire hazard.

SPECIFICATIONS

ELECTRICAL DATA
Switch Rating:
24 VAC (30 VAC max.)
Heating 0.15 to 1.2 amps
Cooling 0 to 1.5 amps
Switch Action:
SPST sealed mercury switch
Anticipator Rating:
Heating adjustable from 0.15 to 1.2 amps
Cooling fixed 24 VAC

THERMAL DATA
Temperature Range:
Heat 50°F to 90°F (10°C to 32°C)
Differential:
1°F (0.6°C)

INSTALLING YOUR THERMOSTAT

CHECK THERMOSTAT LOCATION
You should install your thermostat about five feet (1.5 meters) above the floor in an area with good air circulation and average temperature. Normally, you can simply replace your old thermostat with your new one.
However, you may consider changing the thermostat’s location if the thermostat is affected by:

• drafts or dead air spots behind doors and in corners.
• direct exposure to hot or cold air blowing from ducts.
• direct exposure to sunlight or heat from appliances.
• pipes or chimneys located behind the wall where the thermostat is located.
• unheated areas behind the thermostat, such as an outside wall.

ROUTE WIRES TO LOCATION

1. If you are replacing an old thermostat and the wiring and location are satisfactory, use existing wiring. If in doubt, rewire.
2. If you choose a new location or if this is a new installation, thermostat wire must first be run to the selected location. All wiring must conform to local and national electrical codes and ordinances.
3. Probe for obstructions in partition before drilling 1⁄2” hole in wall at selected location. Take up quarter round (if necessary) and drill a small guide hole for sighting (see fig. 1). From basement, drill a 3⁄4” hole in partition floor next to guide hole. In houses without basements, drill 1⁄2” hole through ceiling and into partition from above.
4. Through this hole, drop a light chain or 6” chain attached to astrong cord. Snag cord in basement with hooked wire. In houses without basements, drop cord through hole in ceiling and down partitioning; snag the cord at thermostat location.
5. Attach thermostat wire to cord or chain and pull wire through hole in wall so that at least 6” of wire protrudes.

WIRE AND ATTACH THERMOSTAT
CAUTION
To prevent electrical shock and/or equipment damage, disconnect electrical power to system, at main fuse or circuit breaker box, until installation is complete.
NOTE
The typical wiring diagrams (figs. 2 through 5) show only the terminal identification and wiring hookup. Always refer to wiring instructions provided by equipment manufacturer for system hookup operation.
All wiring must conform to national and local electrical codes and ordinances.

1. Remove cover from thermostat by gripping the base in one hand. Use the other hand to pull gently at the top or bottom of the cover.
2. Carefully remove the shipping protective packing from the switch.
3. Pull wires through the opening in the thermostat base and connect wires beneath the terminal screws (see figs. 2 through 6).
4. Push excess wiring back into wall and plug hole with fireresistant material (such as fiberglass insulation) to prevent drafts from affecting thermostat operation.
5. Position thermostat base over hole in wall and mark mounting hole locations on wall.
6. Drill mounting holes.
7. Fasten base loosely to wall using mounting screws. Place a level against the top of the thermostat base, adjust until level, and tighten mounting screws to secure base. If holes in wall are too large and do not allow you to tighten the mounting screws securely, use plastic screw anchors.
8. Snap the cover on the thermostat base and set temperature lever to desired setpoint.
9. Turn on electrical power to the system.

All wiring diagrams are for typical systems only. Always refer to equipment manufacturer’s instructions for system hookup operations.
CAUTION
Do not allow wiring to pinch between the subbase and the wall. Be certain that the pivot post that protrudes from the rear of the thermostat does not rub the insulation of any wires. Tighten all screws securely – some serve as electrical connections.
Electric Heat Furnaces (Single Transformer Systems Only)
The subbase as shipped may not operate the fan correctly. If both the heating and cooling system must operate the fan relay, remove the moveable yellow jumper wire from the Y terminal and connect it to the A terminal. The fan should now cycle when the thermostat calls for either heat or cool.

Two-Transformer Systems
CAUTION
If two transformers are used, they MUST be in phase. Failure to do so will result in personal and/or property damage.
Heat Pump Applications
This subbase WILL NOT provide multi-stage heating or cooling. For single stage applications, install a short jumper wire across terminals W and Y. If the old thermostat has a terminal that is continuously energized, disconnect the wire from the old thermostat’s terminal and connect it either to the: (1) B terminal, if the reversing valve is energized on a call for heat; or to the (2) O terminal, if the reversing valve is energized on a call for cool. If the system heats on a call for cool or vice versa, this wire has been connected to the wrong terminal.

NOTE
RH and RC must be jumpered for single transformer heat pump systems.
Special Function Terminals
The B and O terminals can provide switching for special functions other than heat pump operation. When the system switch is in the HEAT position, the B terminal is energized. When the system switch is in the COOL position, the O terminal is energized.

![Doit 474053 Low Voltage Thermostat

• Attach thermostat to subbase](https://manuals.plus/wp- content/uploads/2024/03/Doit-474053-Low-Voltage-Thermostat-Attach-thermostat- to-subbase.png)

OPERATING YOUR THERMOSTAT

The thermostat is easy to operate. Fig. 8 shows how the heating/ cooling system and fan work when the switches are in various positions. Use the system switch to select either heating or cooling, or to turn the heating/cooling system off. Use the fan switch to control fan operation. When the fan switch is in the AUTO position, the fan will cycle with the heating or cooling system (the fan will not run if the system switch is in the OFF position and the fan switch is in the AUTO position). When the fan switch is in the ON position, the fan will run continuously, regardless of system switch position (even if the system switch is set to OFF, the fan will run if the fan switch is in the ON position).

furnace
| | Heating system cycles from thermostat; fan runs continuously

Figure 8. Subbase switching and thermostat/system operation

MAINTAINING YOUR THERMOSTAT

ADJUSTING HEAT ANTICIPATOR
CAUTION
The adjustable heat anticipator WILL BURN OUT if 25 VAC is applied directly to the thermostat by shorting out the primary control during testing. This may cause personal injury and/or property damage.
This thermostat is equipped with and adjustable heat anticipator and was preset at the factory to provide satisfactory operation of the system under normal conditions. If additional adjustments are necessary, they may be made as follows (see fig. 9).

1. Remove thermostat cover.
2. If heat cycle is too long, set heat anticipator to a slightly lower dial setting (about 1⁄2 division at a time). If heat cycle is too short, set heat anticipator to a slightly higher dial setting (about 1⁄2 division at a time).
3. Replace thermostat cover.

CALIBRATING THERMOSTAT
This thermostat has been carefully adjusted at the factory and should not require recalibration. A few degrees of difference between the indicator setting of the thermostat and the actual room temperature is normal. If the disagreement is appreciable, however, first make sure that the thermostat is properly located and leveled, and that the cover thermostat matches the room temperature. If recalibration is still necessary, proceed as follows.
CAUTION
To prevent electrical shock and/or equipment damage, disconnect electrical power to system until recalibration is complete.

1. The anticipator’s heat may adversely affect thermostat recalibration. To prevent this, disconnect electrical power to the thermostat at furnace, main fuse, or circuit breaker box.
2. Move temperature adjustment lever to a setting at least 5°F above room temperature.
3. Remove thermostat cover. Slip 7⁄32” calibration 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 (see fig. 10).
4. Move temperature adjustment lever to lowest setting.
5. Replace thermostat cover. Wait at least 10 minutes 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 match actual room temperature. Remove thermostat cover.
7. Slip 7⁄32” calibration wrench onto hex nut. While holding temperature adjustment lever stationary, turn hex nut counterclockwise until mercury just barely shifts to the left end of the tube.
8. Replace thermostat cover and set temperature adjustment lever to the desired setpoint. Turn on electrical power to the system and thermostat.

NOTES
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Part No. 37-6452A
0248

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