Honeywell Thermostat Q674 User Manual - Honeywell Thermostat Manual Download

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Sunday, April 5, 2020

Honeywell Thermostat Q674 User Manual

T874H,Q,W Multistage Thermostats and Q674B,C,G,L Subbases INSTALLATION INSTRUCTIONS APPLICATION When an LED lights, refer to this list for the meaning: FILTER: clogged filter needs replacement. The T874H,Q,W Multistage Thermostats provide 24 to 30 EM. HT.: emergency heat is operating. The compressor Vac control for heating and cooling systems as listed in has failed, and the heat pump is not operating. The Table 1. LED lights when the homeowner places the system switch in the EM. HT. position. Table 1. Heating and Cooling Stages. AUX. HT.: auxiliary heat is operating because the weather is so cold that the heat pump alone cannot T874 Model handle the load. Stage Ha QW SERVICE or CHECK: system needs to be checked. See heating system instructions for specific Heating Stages 1 1 3 meaning. Cooling Stages 1 — 2 LEDs are not field addable or replaceable. a Plus a changeover stage that operates with cooling. The Q674B,C,G,L Subbases provide wiring terminals, RECYCLING NOTICE system and fan switching, and mounting bases for T874 Multistage Thermostats as listed in Table 2. This control contains mercury in a sealed tube. Do not place the control in the trash at the end of its Table 2. Switching Positions. useful life. Q674 Switch Positions If this control is replacing a control that contains Model System Fan mercury in a sealed tube, do not place your old control in the trash. B Heat-Off-Cool Auto-On C Off-Auto Auto-On Contact your local waste management authority for instructions regarding the recycling and the proper G Off-Auto None disposal of this control, or of an old control L Em Ht-Heat-Off-Cool Auto-On containing mercury in a sealed tube. OPERATION On a two-stage or three-stage heat thermostat, the stages INSTALLATION of heat make sequentially as the temperature drops. Make refers to the mercury switch initiating a call for heat or cool. When Installing this Product… There are about 2°F (1°C) between the stages so that the Read these instructions carefully. Failure to follow second stage makes only when the first stage can not them could damage the product or cause a hazard- handle the load. About one degree later, the third stage ous condition. makes (T874W only). This degree difference is called the Check the ratings given in the instructions and on interstage differential. the product to make sure the product is suitable for your application. Select models include LEDs (light-emitting diodes). The Installer must be a trained, experienced service LED lights to indicate a problem with the system; refer to technician. the system manufacturer instructions. After installation is complete, check out product operation as provided in these instructions. Copyright © 1996 Honeywell Inc. ¥ ¥ All Rights Reserved X-XX UL 69-0087-6 T874H,Q,W MULTISTAGE THERMOSTATS AND Q674B,C,G,L SUBBASES VERTICAL MOUNTING OUTLET SCREWS (2) CAUTION BOX 1 1. Disconnect the power supply to prevent COVER electrical shock or equipment damage. ADAPTER PLATE 2 2. Run the wires as close as possible to the RING 2 subbase. To prevent interference with the thermostat linkage, keep the wire length to a minimum. Push the excess wire back into the hole, and plug the hole to prevent drafts from affecting the thermostat operation. 1 3. Do not tighten the thermostat captive mount- HORIZONTAL OUTLET ing screws to the point of damaging the BOX subbase threads. 4. Do not short across the coil terminals on the relay. This can burn out the heat anticipator. 5. Never install more than one wire per terminal unless a factory-supplied jumper with a spade terminal is used. THERMOSTAT L IMPORTANT OO THERMOSTAT C 0 0 8 0 7 COVER These thermostats are calibrated at the factory 0 6 5 by using subbases mounted at true level. 0 SUBBASE 0 8 0 7 50 6 AT Inaccurate subbase leveling causes thermostat HE control deviation. SUBBASE MOUNTING SCREWS (2) 80 0 7 60 Location CAPTIVE 50 Install the thermostat about 5 ft (1.5m) above the floor in MOUNTING SCREWS (2) an area with good air circulation at average temperature. 1 NOT INCLUDED WITH UNIT. Do not install the thermostat where it can be affected by: 2 ACCESSORY PARTS AVAILABLE (193121A). M6009 — drafts, or dead spots behind doors and in corners. — hot or cold air from ducts. Fig. 1. Installation on vertical or horizontal outlet box. — radiant heat from sun or appliances. — concealed pipes and chimneys. — unheated (uncooled) areas behind the thermostat such as an outside wall. TOP WIRING THERMOSTAT MOUNTING TERMINAL CABLE OPENING SPIRIT LEVEL HOLES (2) Mounting and Wiring the Subbase Mount the subbase on a wall or horizontal outlet box. If you mount it on a vertical outlet box, order Honeywell part no. 193121A Adapter Assembly, which includes an adapter ring with two screws, and a cover plate to cover the marks on the wall. All wiring must comply with local electrical codes and ordinances. Follow the equipment manufacturer wiring instructions, when available. To install the subbase: MOUNTING POST (2) FOR TO SPRING FINGER Prepare a hole for the thermostat wires at the HOLES (2) MOUNTING CONTACTS ON THE THERMOSTAT chosen location. Run wires to the location. THERMOSTAT (UP TO 12) M927 Pull about 6 in. (152 mm) of wire through the hole. IMPORTANT Fig. 2. Leveling subbase. Use 18 gauge, color-coded thermostat cable for proper wiring. Connect the system wires to the subbase. See Fig. 4 through 9. A letter code for identification is When mounting the subbase on a vertical outlet box, located near each terminal. The terminal barrier install an adapter ring with the two screws provided permits straight or conventional wraparound wiring with the adapter assembly. See Fig. 1. connections. See Fig. 3. Either method is accept- Pull the wires through the cover plate (if used) and able. Run the wires as close as possible to the the subbase wire opening. Secure the cover plate subbase, keeping the wire length to a minimum. and subbase with the two screws provided, but do Push the excess wire back into the hole. Plug the not fully tighten. hole to prevent drafts. The subbase mounting slots provide for minor out- of-level adjustments. Level the subbase by using a IMPORTANT spirit level and tightening the subbase mounting An incorrectly leveled subbase causes the screws. See Fig. 2. temperature control to deviate from the setpoint. 69-0087—6 2 T874H,Q,W MULTISTAGE THERMOSTATS AND Q674B,C,G,L SUBBASES FOR STRAIGHT Mounting C815A Thermistor (T874W only) INSERTIONÐ FOR WRAPAROUNDÐ The T874W is used with the C815A Thermistor mounted in STRIP 5/16 in. (8 mm) STRIP 7/16 in. (11 mm) the outdoor section. Locate it in an area where it can measure the true outdoor ambient temperature. Avoid mounting the C815A in an area where it is exposed to high temperatures or direct sunlight. Refer to heat pump BARRIER equipment instructions for proper mounting. SUBBASE TERMINAL SCREW M928 Fig. 3. Wiring connections. THERMOSTAT SUBBASE SYSTEM COMPONENTS 2 Y1 H1 ANTICIPATOR COOL CHANGEOVER FALL 3 VALVE H1 FAN SWITCH 4 FAN RELAY AUTO G ON R Y2 SYSTEM 8 SWITCH COMPRESSOR OFF CONTACTOR RISE B 9 AUTO C1 ANTICIPATOR CO 1 10 O L1 L2 (HOT) 2 RISE X C1 SERVICE LED (YELLOW) COMPRESSOR 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS FAULT AND OVERLOAD PROTECTION AS REQUIRED. C 2 SERVICE LED ON SELECT MODELS. M3680A Fig. 4. T874H/Q674C in heating-cooling system. THERMOSTAT SUBBASE SYSTEM COMPONENTS 2 Y1 H1 ANTICIPATOR COOL CHANGEOVER H1 FAN SWITCH 3 VALVE 1 AUTO FALL G L2 4 ON FAN RELAY R L1 (HOT) COMPRESSOR CONTACTOR Y2 RISE B CO 8 O 9 SYSTEM X SWITCH SERVICE C1 ANTICIPATOR OFF LED (YELLOW) 10 AUTO X1 C1 RISE C 24 VAC 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS FILTER LED (RED) AND OVERLOAD PROTECTION AS REQUIRED. X2 M5902 Fig. 5. T874H/Q674C in heating-cooling system with SERVICE LED and FILTER LED. 3 69-0087—6 T874H,Q,W MULTISTAGE THERMOSTATS AND Q674B,C,G,L SUBBASES THERMOSTAT SUBBASE SYSTEM COMPONENTS H1 ANTICIPATOR 1 W1 3 NO FAN SWITCH CHANGEOVER RELAY FALL B H1 4 W2 H2 ANTICIPATOR 6 FAN RELAY G FALL H2 SYSTEM Y1 8 SWITCH OFF COMPRESSOR 1 CONTACTOR L2 9 AUTO C1 R L1 (HOT) C1 ANTICIPATOR 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND RISE 10 OVERLOAD PROTECTION AS REQUIRED. M6008A Fig. 6. T874Q/Q674G for heating only system. THERMOSTAT SUBBASE SYSTEM COMPONENTS 1 1 L1 (HOT) H1 ANTICIPATOR R FALL H1 C815A THERMISTOR 2 L2 H2 ANTICIPATOR T FAN SWITCH FALL 3 AUTO H3 W1 4 ON HEAT RELAY 1 H3 ANTICIPATOR W2 HEAT RELAY 2 5 W3 FALL SYSTEM HEAT RELAY 3 SWITCH H2 6 B RESET HEATER HEAT HEAT CHANGEOVER VALVE RISE 8 OFF G C1 FAN RELAY C1 ANTICIPATOR COOL 10 O C2 ANTICIPATOR COOL CHANGEOVER VALVE RISE 11 Y2 COMPRESSOR CONTACTOR 2 C2 1 POWER SUPPLY. PROVIDE DISCONNECT Y1 MEANS AND OVERLOAD PROTECTION AS REQUIRED. COMPRESSOR CONTACTOR 1 M3674 Fig. 7. T874W/Q674B with outdoor reset in heating and cooling system. 69-0087—6 4 T874H,Q,W MULTISTAGE THERMOSTATS AND Q674B,C,G,L SUBBASES THERMOSTAT SUBBASE SYSTEM COMPONENTS 1 L1 FALL (HOT) 1 L2 H1 ANTICIPATOR H1 T 2 C815A OD THERMISTOR W3 H2 H2 ANTICIPATOR FALL AUX. HEAT RELAY 3 U FAN SWITCH AUXILIARY HEAT LED (GREEN) H3 ANTICIPATOR AUTO G 4 ON FAN RELAY H3 EMERGENCY HEAT LED FALL R 5 (RED) E 6 RESET COMPRESSOR EM. HEAT RELAY MONITOR L CHECK LED (RED) RISE X 8 SYSTEM SWITCH B C1 EM.HEAT 2 CHANGEOVER 9 RELAY (HEAT) CHANGEOVER HEAT RELAY (COOL) C1 ANTICIPATOR OFF 10 O COMPRESSOR COOL CONTACTOR 1 C2 ANTICIPATOR RISE 11 Y1 COMPRESSOR CONTACTOR 2 C2 12 Y2 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. 2 CONNECT CHANGEOVER RELAY TO 'O' TERMINAL FOR CHANGEOVER IN COOLING OR TO 'B' TERMINAL FOR CHANGEOVER IN HEATING. M156A Fig. 8. T874W/Q674L for three-stage heat and two-stage cool with outdoor reset and compressor monitor. 5 69-0087—6 T874H,Q,W MULTISTAGE THERMOSTATS AND Q674B,C,G,L SUBBASES THERMOSTAT SUBBASE SYSTEM COMPONENTS 1 FALL H1 ANTICIPATOR T H1 2 C815A OUTDOOR THERMISTOR H2 H2 ANTICIPATOR W3 FALL 3 AUX. HT. RELAY FAN SWITCH AUX. HEAT LED (GREEN) AUTO H3 ANTICIPATOR G 4 ON FAN RELAY H3 L1 FALL R (HOT) 5 L2 EM. HEAT 1 LED (RED) E 6 EM. HT. RELAY RESET X1 CHECK LED (YELLOW) C RISE CHANGEOVER 8 SYSTEM RELAY (HEAT) 2 SWITCH B C1 EM.HT. CHANGEOVER RELAY (COOL) 9 HEAT O C1 ANTICIPATOR OFF 10 X2 COOL COMPRESSOR CONTACTOR 1 C2 ANTICIPATOR RISE 11 Y1 COMPRESSOR CONTACTOR 2 C2 12 Y2 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. 2 CONNECT CHANGEOVER RELAY TO 'O' TERMINAL FOR CHANGEOVER IN COOLING OR TO 'B' TERMINAL FOR CHANGEOVER IN HEATING. M6999 Fig. 9. T874W/Q674L for three-stage heat and two-stage cool with outdoor reset. Mounting the Thermostat T874Q only: Set the heat anticipator indicators to Remove the thermostat cover by pulling the bottom the respective current setting for each stage. See edge of the cover upward until it snaps free of the Setting the Heat Anticipator section. T874H and cover clip. T874W have fixed anticipation; the settings are preselected and cannot be adjusted. NOTE: The cover is hinged at the top and must be Note the tabs along the top inside edge of the removed by pulling up at the bottom. thermostat base. The tabs fit into the subbase notches. Mount the thermostat base on the subbase Carefully remove and discard the polystyrene and tighten the captive mounting screws. See Fig. 1. packing insert that protects the mercury switches Place the upper edge of the thermostat cover on the during shipment. thermostat base and swing the cover downward until Turn over the thermostat base and note the spring it engages with the cover clip on the base. fingers that engage the subbase contacts. Make sure the spring fingers are not bent flat, preventing proper electrical contact with the subbase. 69-0087—6 6 T874H,Q,W MULTISTAGE THERMOSTATS AND Q674B,C,G,L SUBBASES 4600 SETTING 4400 4200 4000 C815A THERMISTOR RESISTANCE 3800 R = 400 ohms ± 10% AT 77¡F (25¡C) Setting the Heat Anticipator (T874Q Only) 3600 Set each heat anticipator to match its primary control 3400 3200 current draw. If the primary control nameplate has no 3000 rating or if further adjustment is necessary, use the 2800 following procedure to determine the current draw of each 2600 2400 stage. (Measure the current draw of each heating stage 2200 with the thermostat removed and the power on.) 2000 1800 Connect an ac ammeter of appropriate range 1600 1400 between the heating terminals of the subbase as THERMISTOR RESISTANCE 1200 follows: 1000 Stage 1: between W1 and RH or R. 800 600 Stage 2: between W2 and R. 400 Move the system switch to AUTO (if applicable). 200 0 After one minute, read the ammeter and record the -20 0 20 40 60 80 100 120 140 reading. TEMPERATURE OF THERMISTOR (¡F) M1590A After mounting the thermostat, set the adjustable heat anticipator(s) to match the respective Fig. 10 Thermistor resistance chart. reading(s) measured in step . The proper thermistor operation must be verified to assure Temperature Setting the correct operation of the thermostat. Check the Move the heating and cooling levers to the desired thermistor operation as follows: Disconnect the T wire on the subbase. positions. The minimum differential between the heating and cooling setpoints is 3°F (1.7°C), which means the Use an ohmmeter to measure resistance between ° the T wire and the transformer common. setting levers cannot be set closer together than 3 F (1.7°C) (5° F [2.8°C] for T874W). Take the outdoor temperature at thermistor location and find the correct thermistor resistance on the chart in Fig. 10. Subbase Setting If the resistance measured in step and the System switching positions control thermostat operation as calculated resistance in step vary by more than follows: 15 percent, the thermistor requires replacement. OFF: Both the heating and cooling systems are off. If Contact the installing dealer for the packaged the fan switch is in the AUTO position, the cooling replacement outdoor thermistor. fan is also off. AUTO: Thermostat automatically changes between the heat and cool modes, depending on the indoor temperature. CHECKOUT HEAT: Heating system is controlled by the thermostat. Cooling system is off. Heating EM. HT.: Emergency heat relay is energized. The Move the system switch on the Q674 Subbase to HEAT or cooling system is off. When the compressor has AUTO. Move the heating lever on the T874 about 10°F failed and the heat pump is not operating, switch to (6°C) above room temperature. Both stages of heating the EM. HT. position. start and the fan runs after a short delay. Move the heating lever about 10°F (6°C) below room temperature. The Fan switching positions control fan operation as follows heating equipment shuts off, and the fan runs for a short (Q674B,C, or L): time, and then shuts off. ON: Fan operates continuously. AUTO: Fan operates with cooling equipment as controlled by the thermostat or with the heating Cooling equipment as controlled by the plenum switch. Move the system switch on the Q674 Subbase to COOL or AUTO. Move the cooling lever on the T874 Thermostat To switch positions, use thumb and index finger to slide about 10°F (6°C) below room temperature. The cooling the lever to the desired position. The switch lever must equipment and fan start. Move the cooling lever about stop in detent over the desired function indicator mark for 10°F (6°C) above room temperature. The cooling equip- proper circuit operation. ment and fan stop. C815 Outdoor Reset Thermistor (T874W only) Emergency Heat The T874W is used with a C815 Thermistor mounted in Move the system switch to EM. HT. The EM. HT. LED the outdoor section. The thermistor must be used; if not, comes on. Move the heating lever about 10°F (6°C) above thermostat performance will deviate radically from proper room temperature. The electric strip heater(s) comes on. operation. Move the heating lever about 10°F (6°C) below room temperature. The electric strip heater de-energizes. The EM. HT. LED remains on until the system switch is moved to another postion. 7 69-0087—6 T874H,Q,W MULTISTAGE THERMOSTATS AND Q674B,C,G,L SUBBASES Fan (Select Models) NOTE: Hand heat offsets the thermometer Move the subbase system switch to OFF, and the fan reading. After making each adjustment, switch to ON. The fan runs continuously. When the fan wait 10 or 15 minutes for the thermometer switch is in the AUTO position, the fan operation is to stabilize before comparing. controlled by the heating or cooling system. CALIBRATION Thermostat T874 Thermostats are accurately calibrated at the factory. They do not have provision for field calibration. Thermometer Remove the thermostat cover by pulling up from the bottom of the cover until it clears the locking springs. Set the cover on a table near an accurate thermom- eter. After allowing 10 or 15 minutes for stabilization, compare the readings. If they are the same, replace the cover and put the system into operation. If they are different, recalibrate the thermostat thermom- eter; see step Insert a small screwdriver into the thermometer shaft M5070 and turn it until the thermometers read the same. See Fig. 11. When the thermometer is calibrated, Fig. 11. Thermometer calibration. replace the cover and place the system into operation. Automation and Control Solutions Honeywell Internationl, Inc. Honeywell Limited-Honeywell Limitée 1985 Douglas Drive North 35 Dynamic Drive Golden Valley, MN 55422 Scarborough, Ontario M1V 4Z9 Printed in U.S.A. on recycled paper containing at least 10% 69-0087—6 C.H. Rev. 9-96 8 post-consumer paper fibers. www.honeywell.com

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