Related Manuals for Mars 70803
Summary of Contents for Mars 70803
- Page 1 70803-IM 12/18/06 2:10 PM Page 1 ® 70803 Model INSTALLATION AND OPERATING INSTRUCTIONS Non-Programmable Electronic Thermostat Heat/Cool...
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Page 2: Specifications
70803-IM 12/18/06 2:10 PM Page 2 Compatible with low voltage single stage gas, oil or electric heating or cooling systems and single stage heat pumps. For use on 24VAC systems (not to exceed 30VAC) and 250mv to 750mv millivolt heating only systems. - Page 3 70803-IM 12/18/06 2:10 PM Page 3 Removing The Existing Thermostat 1) CAUTION: Make certain the power to the system has been disconnected. 2) Remove the cover of the old thermostat and locate the wires that are connected to the terminal board.
- Page 4 70803-IM 12/18/06 2:10 PM Page 4 • GAS / ELECTRIC: Configures the thermostat to either gas/oil or electric heating systems. • C / F: Sets the display in either Celsius or Fahrenheit. • NORM / HP: Configures the thermostat for normal heating/cooling systems or heat pump systems (sin- gle stage).
- Page 5 70803-IM 12/18/06 2:10 PM Page 5 4) Set the system switch to the HEAT position and depress the red Image shows room temperature arrow key until the temperature set point is at least 3 degrees of 70 and HEAT set point of 73.
- Page 6 70803-IM 12/18/06 2:10 PM Page 6 When the desired setting is made, release the key and the unit will automatically store the setting after 5 seconds. Cooling Fan Time Delay is factory set at 60 seconds. When the thermostat is set in the COOL position, the system blower will continue to circulate air for a period of 60 seconds after the compressor(s) has shut off.
- Page 7 70803-IM 12/18/06 2:10 PM Page 7 Understanding Additional Features • High Temperature Protection: While in the HEAT position, if the room temperature reaches 93 F (34 C), the thermostat will automatically shut off. In the unlikely event the room temperature reaches 99 F (37 c), a mechanical bimetal switch will shut off the thermostat.
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Page 8: Troubleshooting
70803-IM 12/18/06 2:10 PM Page 8 Troubleshooting SYMPTOM CORRECTIVE ACTION Display is blank Install 2 fresh AA Alkaline batteries No heat Set system switch to HEAT and raise set point above room temperature. Check thermostat wiring and connections. Check pilot light or HSI system on furnace. - Page 9 70803-IM 12/18/06 2:10 PM Page 9 (Troubleshooting cont.) SYMPTOM CORRECTIVE ACTION Set fan switch to AUTO. System fan runs continuously Check thermostat wiring & connections. HI is displayed Reduce room temperature or allow a newly installed thermostat to acclimate. HI indicates a room temperature reading greater than 90 F (32 C).
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Page 10: Wiring Diagrams
70803-IM 12/18/06 2:10 PM Page 10 Wiring Diagrams Typical 5-Wire System COOL HEAT CONTROL CONTROL CONTROL COOL 24 VAC HEAT 24 VAC TRANSFORMER TRANSFORMER Inst... - Page 11 70803-IM 12/18/06 2:10 PM Page 11 Wiring Diagrams Typical Single Stage Heat Pump System Install Jumper Install Jumper REV. VALVE CONTROL COOL ENERGIZED COMPRESSOR REV. VALVE CONTROL HEAT ENERGIZED 24 VAC TRANSFORMER...
- Page 12 70803-IM 12/18/06 2:10 PM Page 12 Wiring Diagrams Typical 2-Wire Millivolt System HEAT CONTROL 24 VAC TRANSFORMER...
- Page 13 70803-IM 12/18/06 2:10 PM Page 13 Wiring Diagrams Typical 4-Wire System Install Jumper COOL HEAT CONTROL CONTROL CONTROL 24 VAC TRANSFORMER...
- Page 14 70803-IM 12/18/06 2:10 PM Page 14...
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Page 15: One-Year Limited Warranty
Warranty ONE YEAR LIMITED WARRANTY Motors & Armatures Inc. warrants each new MARS thermostat against any defects due to non-conforming material or workmanship for a period of one year after the original date of purchase by a professional service technician and does not include the cost of removal or re-installation. - Page 16 70803-IM 12/18/06 2:10 PM Page 16 INSTALLATION AND OPERATING INSTRUCTIONS Non-Programmable Electronic Thermostat Heat/Cool 70803 Model ®...
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