HTP Error Code F01: Flue temperature switch / low water (Boiler)
HTP error code F01 on a boiler means: Flue temperature switch / low water. It is also called HTP diagnostic code F01.
Homeowner? What HTP code F01 means for you
Stop and call Your boiler is reporting: Flue temperature switch / low water. This code is a safety shutdown. Turn the boiler off and call a licensed technician. Do not keep resetting it. If you smell gas, leave the house and call your gas utility or 911 from outside.
Safe things you can check yourself
- Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
- Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
Call (647) 657-2977Book a service call
Licensed technicians serving Vaughan, Toronto and the GTA.
What does HTP error code F01 mean?
Flue temperature limit switch tripped or, if the optional UL353 LWCO is fitted, water level is low. Lockout with pump on. Control: FAULT light red steady and LOCKOUT shown on lower line; reset with RESET held over 1 second after repair.
Applies to: EL-80, EL-110, EL-150, EL-220, EL-299, EL-399 (N/LP)
Common causes of HTP code F01
- Low water level (UL353 LWCO installed)
- Flue obstructed or overheated
- Flue temperature switch failed
A technician checks these and 1 other possible causes on site before replacing any part.
HTP models that use code F01
EL-80 LPEL-80 NEL-110 LPEL-110 NEL-150 LPEL-150 NEL-220 LPEL-220 NEL-299 LPEL-299 NEL-399 LPEL-399 N
Other HTP Boiler codes
HTP code F01: homeowner questions
What does HTP code F01 mean?
Flue temperature switch / low water. Flue temperature limit switch tripped or, if the optional UL353 LWCO is fitted, water level is low. Lockout with pump on. Control: FAULT light red steady and LOCKOUT shown on lower line; reset with RESET held over 1 second after repair.
Is it safe to keep using my boiler with code F01?
No. Code F01 is a safety shutdown, so keep the boiler off until a licensed technician has checked it.
Can I reset HTP code F01 myself?
Do not keep resetting it. Repeated resets can hide a safety problem; a licensed technician needs to find the cause.
Who can fix HTP code F01 near me?
Aurora Star Tech Inc. repairs HTP boilers in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.
Homeowner help: Boiler Not Heating: What to Check
Troubleshooting guides
- Condensing/corrosion of conventional boiler All brands · Boiler
- No heat or some zones cold All brands · Boiler
- Noise All brands · Boiler
- Poor heat / circulation All brands · Boiler
- Relief valve weeps every cycle / pressure climbs All brands · Boiler
- Short cycling / wasted fuel All brands · Boiler
- Symptoms of air in system All brands · Boiler
- Uneven heating All brands · Boiler
- Won't fire All brands · Boiler
- Boiler overheating lockout (F00, F05, F06) HTP · Boiler
- Cascade set-up HTP · Boiler
- Check thermostat circuit for stray voltage HTP · Boiler
- False flame signal with burner off (F11) HTP · Boiler
- Fan speed error (F13) HTP · Boiler
- Flame drops out while running (F10) HTP · Boiler
- Lockout on ignition (F09, no flame) HTP · Boiler
- Menu access codes HTP · Boiler
- Pump service mode to purge air HTP · Boiler
- Read fault history HTP · Boiler
- Reset a lockout HTP · Boiler
- Reset the maintenance reminder HTP · Boiler
- Start-up combustion and gas checks HTP · Boiler
- Test mode (fixed-fire, gas pressure and combustion) HTP · Boiler
- Thermostat calling but boiler not firing HTP · Boiler
Source: Elite EL-80 N Installation Manual (LP-293), p. 69. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.