Instruction/ maintenance manual of the product T874/Q674 Honeywell
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S . M. • Rev. 5-93 • • ©Honeywell Inc. 1993 • Form Number 60-1147—4 T874/Q674 Thermostat/Subbase Combinations Installation Instructions for the Trained Service Technician. Application The T874/Q674 Thermostat/Subbase combinations provide 24 to 30 Vac control for heat pump systems.
60-1 147-4 2 Fig. 1—Installation of Q674 Subbase on outlet box. M925 VERTICAL OUTLET BOX ADAPTER RING SUBBASE COVER PLATE MOUNTING SCREWS (2) MOUNTING SCREWS (2) 1 SUBBASE MOUNTING SCREWS (2) HORIZONTAL OUTLET BOX 1 2 2 1 NOT INCLUDED WITH UNIT. 2 ACCESSORY PARTS AVAILABLE (193121A).
60-1 147-4 3 Fig. 4—Wiring connections. 2. Carefully remove and discard the polystyrene packing insert that protects the mercury switches during shipment. 3. If LED indication (EM.HT., CHECK, etc.) is to be used with the Q674 Subbase, install the preprinted insert under the thermostat set point scale (Fig.
60-1 147-4 4 Fig. 6—Internal schematic and typical wiring diagram for T874N and Q674F. L1 HOT L2 1 W1 W2 EM. HEAT LED (RED) CHECK LED (GREEN) FAN RELAY G EM. HEAT RELAY COMPRESSOR CONTACTOR Y E SYSTEM SWITCH EM. HT. HEAT OFF COOL H1 ANTICIPATOR H1 H2 H2 ANTICIPATOR 1 POWER SUPPLY.
60-1 147-4 5 Fig. 7—Internal schematic and typical wiring diagram for T874R and Q674L. L1 HOT L2 1 X2 W2 EM. HEAT LED (RED) AUX. HEAT LED (GREEN) HIGH LIMIT SWITCH FAN RELAY G EM. HEAT RELAY COMPRESSOR CONTACTOR Y E SYSTEM SWITCH EM. HT. HEAT OFF COOL H1/C1 ANTICIPATOR H1 H2 H2 ANTICIPATOR 1 POWER SUPPLY.
60-1 147-4 6 Fig. 9—Mounting thermostat on subbase. THERMOSTAT MOUNTING POST (2) M936 50 60 70 80 50 60 70 80 HEAT COOL THERMOSTAT MOUNTING SLOTS (2) SUBBASE THERMOSTAT CAPTIVE MOUNTING SCREWS (2) Settings HEAT ANTICIPATOR SETTING Set the adjustable heat anticipator to match the current draw of the second stage heating primary control (Fig.
60-1 147-4 7 Checkout HEATING Move the system switch on the Q674 to HEAT or AUTO (if used) and the fan switch to AUTO. Move the heating set point lever on the T874 about 10 ° F [6 ° C] above room temperature. Heating equipment should start and the fan should run.
60-1 147-4 8 Honeywell Limited-Honeywell Limitée 35 Dynamic Drive Scarborough, Ontario M1V 4Z9 60-1 147 –4 S.M. Rev . 5-93 Automation and Control Solutions Honeywell International Inc. 1985 Douglas Drive North Golden Valley, MN 55422 www.honeywell.
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However, one of the most important roles played by the user manual is to help in solving problems with Honeywell T874/Q674. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Honeywell T874/Q674 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
