Honeywell TRADELINE Y594 Installation, Instruction And Service Manual

Honeywell TRADELINE Y594 Installation, Instruction And Service Manual


These Y594G and Y594J combination packs are designed to meet the specific requirements of Carrier heat pump equipment. The Y594 packs are designed for 2 stage heat and 1 stage cool applications. The system switch is SUPL HT-HEAT-OFF-COOL or SUPL HT-ON-OFF. The fan switch is AUTO-ON. See Table 1 for model information and cross reference from Carrier part numbers.

Honeywell TRADELINE Y594 Subbase Ratings

SWITCH RATING: 7.5A inrush, 2.5A running at 30 Vac.

SWITCHING: sealed mercury switch.

First Stage Heating and Cooling: 6.5A inrush, 1.5A maximum running at 25 Vac.
Second Stage Heating and Cooling: 1.5A maximum running at 30 Vac.
Changeover Switch: 6.5A inrush, 1.5A running at 25 Vac.

First Stage Heating and Cooling: fixed voltage type, 1.0A.
Second Stage Heating: adjustable, 0.10 to 1.2A; other models, fixed voltage type, 1.0A.
TEMPERATURE SETTING RANGE: 42°F to 88°F (6°C to 31°C).
MOUNTING: Designed for mounting on wall or horizontal outlet box.


The two stages of heat are energized sequentially with changes in temperature. Stage one comes on first; then if the temperature at the thermostat continues to move away from the setpoint, the second stage comes on. The thermostat is set with about 2°F (1°C) between stages. As the heating equipment runs and the temperature begins to move back toward the set point, stage 2 goes off first, then stage one.

Subbases include an LED (light emitting diode) indicator. This indicator lights to show that the heat pump cannot operate and the supplemental heat stage is providing all heating. This condition can occur in two instances; when the subbase system switch is set at SUPL. HT. and when the heat pump compressor has malfunctioned. The LEDs are not field replaceable.


When Installing this Product…

  • Read these instructions carefully. Failure to follow them could damage the product or 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.


  • Disconnect power supply to prevent electrical shock or equipment damage.
  • Run wires as close as possible to the subbase. 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.

Thermostats are calibrated at the factory by using subbases mounted at true level. Inaccurate subbase leveling will cause thermostat control deviation.

Honeywell TRADELINE Y594 Installation Location

Install the thermostat about 5 ft (1.5m) above the floor in an area with good air circulation at average room temperatures. 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.

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Honeywell TRADELINE Y594 Installation Manual

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