Instruction/ maintenance manual of the product Q674A-E Honeywell
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1 60-1165—6 Q674 Switch Positions Model System Fan A Heat-Auto-Cool Auto-On B Heat-Off-Cool Auto-On C Off-Auto Auto-On D None None E Off-Heat-Auto-Cool Auto-On G Off-Auto None T874A-F Multistage Thermostats/Q674A-E,G Subbases TRADELINE ® Installation Instructions for the Trained Service Technician.
2 60-1165—6 Fig. 1—Installation of subbase on outlet box. 2. Pull electrical wires through the cover plate (if use d) and subbase cable opening (Fig. 3). See Wiring the Subbase section before pulling any wires. IMPORTANT: Use 18 gauge, color-coded thermostat cable for proper wiring.
3 60-1165—6 3. Firmly tighten each terminal screw. 4. Fit wires as close as possible to the subbase. Push exc ess wire back into the hole. 5. Plug hole with nonflammable insulation to prevent drafts from affecting the thermostat. Fig. 5—Jumper RC and RH for single trans- former system.
4 60-1165—6 Fig. 8—T874A-D/Q674A in standard heating/cooling system. Fig. 9—T874C,D/Q674B in standard heating/cooling system with separate transformers for heating and cooling. H1 FALL L1 (HOT) L2 1 RH W1 W2 O G Y2 Y1 RC HEAT RELAY 2 HEAT RELAY 1 HEAT OFF COOL SYSTEM SWITCH H1 ANTICIPATOR C1 ANTICIPATOR AUTO ON FAN SWITCH 2 1 POWER SUPPLY.
5 60-1165—6 Fig. 10—T874D/Q674B in standard heating/cooling system with single transformer for heating and cooling. Exact replacement for York model no.
6 60-1165—6 Fig. 12—T874A,D,F/Q674D in standard heating/cooling system. Fig. 13—T874D/Q674E in standard heating/cooling system..
7 60-1165—6 Fig. 14—T874A-F/Q674G in standard heating/cooling system. Fig. 15—T874C/Q674B in standard application..
8 60-1165—6 Fig. 16—Typical Q674 terminal designations. The thermostat and subbase used determines the number of system components controlled. TEMPERATURE LEVER STOPS Some thermostats have factory-installed temperature lever locking screws (Fig. 17) and/or stop brackets (Fig.
9 60-1165—6 9. Firmly tighten the mounting screw. 10. If the HEAT and COOL levers are to be locked in place at a specific temperature, use the two insulated head screws supplied instead of the two adjustable lever stop brackets. CAUTION Do not use standard screws that provide metal-to- metal contact with the stop brackets.
10 60-1165—6 2. Move the system switch to AUTO or HEAT (if used) . 3. After one minute, read the ammeter and record the reading: Stage 1: __________ amperes. Stage 2: __________ amperes. NOTE: If equipment cycles too fast, set the indicator to a higher current rating, not more than one-half division at a time, and recheck cycle rate.
11 60-1165—6 Calibration THERMOSTAT T874 Thermostats are accurately calibrated at the factory. They do not have provision for field calibration. THERMOMETER The thermometer in the thermostat has been accurately calibrated at the factory. The thermometer should need ad- justment only if it has been dropped or shifted due to mishan- dling.
12 60-1165—6 www.honeywell.com/yourhome Automation and Control Solutions Honeywell International Inc. Honeywell Limited—Honeywell Limitée 1985 Douglas Drive North 35 Dynamic Drive Golden Valley, .
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If you already are a holder of Honeywell Q674A-E, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Honeywell Q674A-E.
However, one of the most important roles played by the user manual is to help in solving problems with Honeywell Q674A-E. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Honeywell Q674A-E 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