Robertshaw Thermostat Troubleshooting

If your Robertshaw Thermostat model is not working correctly, you can perform the troubleshooting process on your own. The guidelines below are presented in the form of tables that describe common thermostat issues, possible causes and solutions of the problems. A wide range of problems is covered stating from the absence of heat and finishing by display malfunctioning. Each manual provides a short description of the troubleshooting process – the guidelines are quite easy to follow.  Please, note that while some tasks can be done by an average user, a few repair measures should be done by professionals only.

Robertshaw RS6110 Thermostat Troubleshooting

ProblemAction
Thermostat does not turn on system.Check wiring
System turns on too often.Increase temperature differential
System fan does not operate properly.Move fan option switch to either gas or electric, to match system
Thermostat does not display proper room temperature.Check F/C (Fahrenheit/Celsius) setting.
Display Shows HI or LO and room temperature is normal.Call a licensed service person to replace/repair.

Robertshaw Smart Sense Smart 1000 Thermostat Troubleshooting

SYMPTOMPOSSIBLE FAULT AND REMEDY
No LCD displayIf the thermostat is battery powered only, remove the battery compartment and check to see that the positive (+) and negative (-) ends of each battery are oriented property. Also make sure that the thermostat is securely attached to the subbase with no exposed gaps.
Thermostat can not be set for auto changeoverInstaller Option 03 needs to be set to 0 to provide Heat/Auto/Cool/Off operation or Heat/Auto/Cool/Emergency Heat/Off for heat pumps.
Temperature display inaccurateAir from wall cavity may be leaking into the rear of the thermostat. Seal hole where wiring enters subbase to prevent air infiltration. External influence from appliances, lighting or drafts may be affecting temperature accuracy. Move lamps or other sources of heat away from thermostat.
Thermostat not displaying outdoor temperatureCheck wiring at outdoor sensor and sensor terminals on subbase.

Robertshaw Slimzone Premier Thermostat Troubleshooting

PROBLEMPOSSIBLE CAUSESOLUTION
No heat/cooling in houseZone thermostat(s)Select heat, cool or auto mode of operation at thermostat
Faulty heating /cooling equipmentTroubleshoot equipment
Faulty thermostatReplace if necessary.
Faulty zone control panelReplace if necessary.
No heat/cooling in zoneBalancing damper closedCheck all balancing dampers in the same duct as the motorized zone damper; closed balancing dampers should be readjusted.
Zone registers closedCheck all zone registers; closed registers should be readjusted.
Faulty thermostatReplace if necessary.

Robertshaw 8405 Thermostat Troubleshooting

SymptomRemedy
Thermostat does not tum on system.Check wiring
Thermostat turns system on and off too frequently.Increase temperature differential
Display is blank, flashing or constant LO BATT.Replace batteries.
System fan does not operate properly.Move Electric/Gas switch to either electric or gas, to match system
Thermostat does not display proper room temperature.Check F/C (Fahrenheit/Celsius) setting.

Robertshaw RS2210 Thermostat Troubleshooting

TROUBLESHOOTING ProblemSolution
SCRAMBLED OR DOUBLE DISPLAY (numbers over numbers)1. Remove clear mylar sticker.
NO DISPLAY1. Check battery connections and batteries.
2. Press the reset button once with a small pm and hold for two seconds then reprogram.
ENTIRE DISPLAY DIMS1. Replace batteries.
AUTO/FAN DOES NOT TURNON1. Move ELEC/GAS selector to opposite position.
2. There may be as much as a 4 minute delay before the heat or cool system turns on. Wait and check.
3. Check your circuit breakers and switches to ensure there is power to the system.
4. Replace batteries.
5. Make sure your furnace blower door is closed property.
6. If your system only uses 4-wires, be sure the jumper wire is installed between the RC and RH terminals.
7. Check the position of the Furnace or Heat Pump selector switches: Normal/O/B.
ERRATIC DISPLAYPress the reset button once with a small pm and hold for two seconds then reprogram.
IF UNIT CONTINUES TO OPERATE IN THE OFF POSITION1. Replace unit.
THERMOSTAT PERMANENTLY READS E1.E2. E3. E41. Replace unit.

Robertshaw Thermostat 9420 Troubleshooting

SymptomRemedy
Thermostat does not turn on system.Check wiring
Thermostat turns system on and off too frequently.Increase temperature differential
Display shows CHECKMonitors system status. Call your local HVAC service provider.
Thermostat does not display proper room temperature.Check F/C (Fahrenheit/Celsius) setting.