Coleman-Mach thermostat · 1 model line
Coleman-Mach thermostat code HI
The Coleman-Mach digital thermostat manual says HI displays when current temperature is above 99 F (37 C).
What code HI means by model
| Model line | What the manufacturer says | Source |
|---|---|---|
| Coleman-Mach 9420-381 / 9420-382 digital thermostats | The Coleman-Mach digital thermostat manual says HI displays when current temperature is above 99 F (37 C). | Coleman-Mach Digital Thermostats 9420-381 & 9420-382 |
What you can safely check
- Compare the thermostat display with room conditions.
- Record whether HI appears continuously or only during heat exposure.
- Avoid changing wiring or internal thermostat settings.
Stop and call a technician for
- Sensor faults, thermostat wiring, PTC fuse issues, and HVAC control diagnosis belong to trained technicians.
Disconnect power before thermostat or HVAC service. Do not probe control wiring unless qualified.
Write this down before you call
- thermostat model
- indoor temperature
- sun/heat exposure near thermostat
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…
- 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 flashing DIFF flashes on the LCD when 2nd stage heat is operating because the heat pump cannot sat…
- 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