Instruction/ maintenance manual of the product T874G Honeywell
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X-XX UL INST ALLA TION INSTRUCTIONS Copyright © 1995 Honeywell Inc. • • All Rights Reserved T874G,R Multistage Heat Pump Thermostats and Q674F ,J,L Subbases APPLICA TION The T874G,R Thermostats with Q674F,J,L Subbases provide 24 to 30 Vac control of a two-stage heating/one- stage cooling heat pump system.
69-0268—1 1 2 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES CA UTION 1. Disconnect power supply to prevent electrical shock or equipment damage. 2. Run wires as close as possible to the subbase. To prevent interference with the thermostat linkage, keep wire length to a minimum.
69-0268—1 1 3 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES H1 FALL RISE CO L1 (HOT) L2 1 3 C1 RISE 1 2 2 3 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. TERMINAL LABELED C/X ON SOME MODELS. W3 TERMINAL ON SOME MODELS ONLY.
69-0268—1 1 4 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES H1 FALL H2 FALL CO RISE C1 RISE L1 (HOT) L2 1 2 1 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. REMOVE JUMPER FOR INDEPENDENT CONTROL OF W1 AND E TERMINALS.
69-0268—1 1 5 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES H2 FALL H1 FALL C1 L1 (HOT) L2 1 2 2 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. FACTORY-INSTALLED JUMPER. THERMOSTAT SUBBASE SYSTEM COMPONENTS H1/C1 ANTICIPATOR H2 ANTICIPATOR SYSTEM SWITCH FAN SWITCH AUTO ON OFF HEAT EM.
69-0268—1 1 6 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES H2 FALL H1 FALL C1 L1 (HOT) L2 1 1 2 2 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. REMOVE JUMPER FOR INDEPENDENT CONTROL OF W1 AND E TERMINALS.
69-0268—1 1 7 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES H1 FALL C L1 (HOT) L2 1 EM. HT. LED (RED) AUX. HT. LED (GRN) W3 O L G R W2 E X X2 B W1 Y AUX.
69-0268—1 1 8 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES M5072A (HOT) L1 L2 1 LACO CHP Y B E O G L X W2 W3 R ODT 1 RTD 1 EHR 1 RTD 2 ODT 2 EHR 2 RTD 3 RD SYSTEM MONITOR FAN RELAY COMPRESSOR CONTACTOR COOL CHANGEOVER VALVE EM. HT.
69-0268—1 1 9 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES Fig. 10. Internal schematic and typical wiring diagram for T874R/Q674L in heat pump system. Includes EM. HT. and AUX. HT. LEDs. L1 (HOT) L2 1 X L W2 EM. HT. LED (RED) AUX.
69-0268—1 1 10 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES M1627A R W E X L1 (HOT) L2 COOL EM. HT. HEAT SYSTEM SWITCH AUTO ON FAN SWITCH 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. REMOVE JUMPER FOR INDEPENDENT CONTROL OF W AND E TERMINALS.
69-0268—1 1 11 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES THERMOSTAT MOUNTING POST (2) M3266 50 60 70 80 HEAT THERMOSTAT MOUNTING SLOTS (2) SUBBASE THERMOSTAT CAPTIVE MOUNTING SCREWS (2) Fig.
69-0268—1 1 12 T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES Home and Building Control Honeywell Limited-Honeywell Limitée 35 Dynamic Drive Scarborough, Ontario M1V 4Z9 69-0268—1 1 J.S. Rev . 12-95 If the setpoint lever setting and the thermometer reading do not agree, follow the procedure below.
An important point after buying a device Honeywell T874G (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Honeywell T874G yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Honeywell T874G - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Honeywell T874G you will learn all the available features of the product, as well as information on its operation. The information that you get Honeywell T874G will certainly help you make a decision on the purchase.
If you already are a holder of Honeywell T874G, 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 T874G.
However, one of the most important roles played by the user manual is to help in solving problems with Honeywell T874G. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Honeywell T874G 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
