Honeywell T87F Universal Thermostat Installation Instructions
Installation Instructions for the Trained Service Technician.
Application
The T87F Universal Thermostat provides temperature control for 24 to 30 Vac residential heating, cooling or heating-cooling systems. For heating systems, the T87F mounts on the wallplate provided. For cooling only, or heating-cooling, order the 137421A (198170A if textured designer model) Heating-Cooling Wallplate with remote switching, or the Q539 Subbase, which provides switching at the thermostat location.
The spdt switch makes one set of contacts on a temperature fall to operate the heating system. The other set of contacts make on a temperature rise to operate the cooling system when the T87F is used to control cooling.
Heat anticipation is adjustable, 0.1 to 1.2 A.
Mercury Notice
This control contains mercury in a sealed tube. Do not place control in the trash at the end of its useful life.
If this control is replacing a control that contains mercury in a sealed tube, do not place your old control in the trash.
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.
If you have questions, call Honeywell Inc. at 1-800-468-1502.
Installation and Setting
WHEN INSTALLING THIS PRODUCT...
- Read these instructions carefully. Failure to follow them could cause a hazardous condition.
- Check the ratings given in the instructions and on the product to make sure the product is suitable for your application.
- Installer must be a trained, experienced service technician.
- After installation is complete, check out product operation as provided in these instructions.
CAUTION
- Disconnect power supply to prevent electrical shock or equipment damage.
- To prevent interference with the thermostat linkage, keep wire length to a minimum and run wires as close as possible to the subbase.
- Do not overtighten thermostat captive mounting screws because damage to subbase threads can result.
- Do not short across coil terminals on relay. This can burn out the thermostat heat anticipator.
An incorrectly leveled thermostat will cause the temperature control to deviate from set point.
LOCATION
Install the thermostat about 5 ft [1.5 m] above the floor in an area with good air circulation at average temperature.
Do not install the thermostat where it may be affected by:
- Drafts, or dead spots behind doors and in corners.
- Hot or cold air from ducts.
- Radiant heat from sun or appliances.
- Concealed pipes and chimneys.
- Unheated (uncooled) areas such as an outside wall behind the thermostat.
This thermostat is a precision instrument and was carefully adjusted at the factory. Handle it carefully.
MOUNTING WALLPLATE OR SUBBASE (Fig. 2)
1. Use a spirit level to accurately level the wallplate or subbase as in Fig. 1. Inaccurate leveling may cause thermostat control deviation.
2. When using the T87F with a Q539 Subbase, follow the mounting and wiring instructions included with the subbase.
- Place the wallplate on the wall at the desired location. Pull the thermostat cable through the entrance hole.
- Fasten wallplate. Do not tighten the screws.
- Level according to Fig. 1 then tighten screws.
- After wiring wallplate, plug hole to prevent drafts from affecting thermostat.
NOTE: To mount T87 Thermostat on an outlet box, order 129044A Adapter Ring Assembly.
Fig. 1: Leveling wallplate or subbase with spirit level or plumb line. The diagram shows a spirit level being used to ensure the wallplate or subbase is level, with leveling posts indicated.
Fig. 2: Mounting wallplate or subbase to wall. The diagram illustrates attaching the wallplate to the wall using screws, with openings for thermostat cable entrance. It also shows how to add the T87F as shown on outlet box mounting.
WIRING
All wiring must comply with local electrical codes and ordinances. Disconnect power supply before connecting wiring to prevent electrical shock or equipment damage.
The T87F is adaptable to most 2-wire, 24 to 30 volt heating systems, and to most 3-wire, 24 to 30 volt heating systems controlled by a Series 10 Thermostat. The following hookups are typical applications. See Figs. 3 through 7. When using the T87F for cooling control, refer to the hookups in the Q539 Subbase instructions.
For variations of these systems, refer to the installation instructions for the controlled equipment.
After wiring the wallplate, plug the hole to prevent drafts that may affect the thermostat.
Fig. 3: T87F used for 2-wire, spst control of heating only in a typical oil system.
The diagram shows a wiring schematic for a typical oil heating system. It includes connections for the thermostat (Y, R, W), an R8184G Protectorelay, a cad cell, and the burner motor, ignition, and oil valve. Power supply notes are included.
Fig. 4: T87F used for 2-wire, spst control of heating only in a typical gas system.
The diagram illustrates a wiring schematic for a typical gas heating system. It shows connections for the T87F thermostat, a 137421A wallplate, a combination fan and limit control, a gas valve, and a transformer. Power supply notes are included.
Fig. 5: T87F replacing a Series 10 Thermostat connected to a 3-wire, open-contact, high-limit control.
This diagram shows the wiring for replacing a Series 10 Thermostat. It includes connections for the T87F, a low limit operating control, and a Series 10 open circuit high limit, with connections to a valve or motor at the burner.
Fig. 6: T87F used for Series 20, 3-wire, spdt control of low-voltage motors and electric radiator valves.
The diagram depicts wiring for a Series 20, 3-wire, spdt control system. It shows connections for the T87F, a 137421A wallplate, and a three-wire spdt valve or motor. Power supply notes are included.
Fig. 7: T87F used in cooling-only system.
This diagram illustrates the wiring for a cooling-only system. It shows connections for the thermostat wallplate or subbase, a cooling contactor coil, and the power supply. It notes that only R and Y terminals are used for cooling only.
MOUNTING THERMOSTAT TO WALLPLATE OR SUBBASE
To remove the standard cover, pull the ring outward with fingertips, pressing lightly on the dial with thumbs.
To remove the locking cover, loosen the three screws along the cover edge with the supplied Allen wrench. Remove the cover as indicated above.
Remove and discard the plastic insert protecting the mercury switch.
Align the thermostat over the wallplate and tighten the three captive mounting screws. These captive screws complete the electrical connections to the thermostat. Adjust heat anticipator to match the current rating of the primary control. See Fig. 8.
HEAT ANTICIPATOR SETTING
If the T87F is used for 3-wire, spdt, heating-only (Series 20) control (Fig. 6), set the heat anticipator for 1.2 (far left end of scale). A fixed resistor-type heater is provided in the 137421A or 198170A Wallplate for this application. For other control applications, proceed as follows.
Adjust the anticipator to match the current rating of the primary control. The rating is usually stamped on the control nameplate. Move the indicator to the marking that matches this rating. The indicator may be moved with fingers or a pencil point through the hole shown in Fig. 8. If the current rating is not given, proceed as follows before mounting the thermostat:
- Connect an ac ammeter of appropriate range (0 to 2.0 A, for example) between the R and W terminals on the wallplate or subbase.
- Let the system operate for one minute before reading the ammeter.
- Move the anticipator indicator to match the ammeter reading.
A slightly higher setting to obtain longer burner-on times (fewer cycles per hour) may be desirable for some systems.
RECALIBRATION
The T87F is calibrated at the factory and no recalibration should be necessary. If the thermostat is accurately leveled and still appears to be out of calibration, order 104994A Calibration Wrench. Instructions for recalibrating are furnished with the wrench.
Fig. 8: Setting heat anticipator current rating. The diagram shows the scale for setting the heat anticipator, with markings for current ratings and an indicator that can be moved with a pencil point.
Checkout
HEATING
Turn down the temperature setting to the lowest point. If a subbase or remote switching is used, move the system switch to the HEAT position. Raise the temperature setting until the heating equipment starts. This point should be at room temperature as indicated on the thermometer. Slowly turn back the dial. The heating equipment should stop when the dial has been turned below room temperature.
COOLING
1. Do not operate cooling if the outdoor temperature is below 50°F [10°C]. Refer to manufacturer recommendations.
2. Allow a five-minute off-time after the compressor has been run to avoid compressor damage.
If the T87F controls cooling, move the system switch (if used) to call for COOL and lower the setting until the cooling equipment starts. Raise the setting above room temperature and the cooling system should shut down. Make certain all equipment properly responds to the thermostat.
Honeywell Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
Honeywell Limited—Honeywell Limitée
35 Dynamic Drive
Scarborough, Ontario M1V 4Z9
Printed in U.S.A. on recycled paper containing at least 10% post-consumer paper fibers.
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