Coleman-Mach thermostat · 1 model line
Coleman-Mach thermostat: DIFF flashing
The Coleman-Mach 6535-335 thermostat instructions say DIFF flashes on the LCD when 2nd stage heat is operating because the heat pump cannot satisfy the thermostat.
What this message means by model
| Model line | What the manufacturer says | Source |
|---|---|---|
| Coleman-Mach 6535-335 heat pump wall thermostat | The Coleman-Mach 6535-335 thermostat instructions say DIFF flashes on the LCD when 2nd stage heat is operating because the heat pump cannot satisfy the thermostat. | Coleman-Mach 6535-335 2 Stage Heat Pump Wall Thermostat Installation and Operating Instructions |
What you can safely check
- Record thermostat model, displayed word, mode, room temperature, set point, outside temperature estimate, and elapsed lockout time.
- Wait through the manual-described lockout period if the coach stays safe and warm enough.
- After the lockout clears, keep the electric-heat set point within four degrees of room temperature before trying again.
- Use normal backup heat controls during the lockout if available.
Stop and call a technician for
- Thermostat installation, wiring, base fuse, jumper configuration, 12 V electrical diagnosis, heat pump, compressor, furnace, and control-circuit work is trained technician work.
Use normal thermostat controls only. Stop electric heat attempts and call Coleman-Mach/Airxcel or qualified RV HVAC service if lockout repeats, the coach cannot be kept warm, or there are electrical symptoms.
Write this down before you call
- thermostat model
- displayed word
- mode
- set point
- room temperature
Other codes on Coleman-Mach RV thermostats
Full table: Coleman-Mach RV thermostats
- Er Er displays when ambient temperature is outside the thermostat display range or when a re…
- HI HI displays when current temperature is above 99 F (37 C).
- LO LO displays when current temperature is below 33 F (0 C).
- ELEC flashing ELEC flashes when the heat pump is in lockout because electric heat could not satisfy the…
- DIFF DIFF displays when backup heat is operating and the heat pump is locked out. / Coleman-Ma…
- FLASHING GAS HEAT Coleman-Mach's heat pump thermostat guide says FLASHING GAS HEAT can show during the two …
- Solid Green The device being connected to the network and communicating properly
- Off The device having no power or having completely failed
- Solid Red The device being offline and not connected to the network
- Fast Flashing Green (4 Times/Sec) The device attempting to make its initial network connection
- Slow Flashing Green (1 Time/Sec) The device having been online but having no valid network message for 5 seconds
- Alternating Red & Orange The device being offline and attempting to reconnect within 30 seconds
- Alternating Green & Orange The device being currently online but having gone offline 2 or more times