HTP boiler fault indicators generally fall into a handful of categories, ignition, flame loss, venting, flow, and sensor faults, each with its own diagnostic path.
Tell us what you need—we’ll call you back fast.
Quick answer
HTP boiler fault indicators generally fall into a small number of categories: ignition failure, flame loss during operation, venting or exhaust restriction, low water flow or pressure, over-temperature conditions, and sensor faults. The specific indicator shown on your unit's display should always be checked against the owner's manual for your exact model, since the numbering and labelling can vary between HTP product lines and firmware versions.
Need a licensed gas fitter for your gas boiler? Call CANRO at (604) 359-1081 — residential natural-gas heating and hot water across Metro Vancouver since 1999.
HTP has produced several boiler product lines over the years, and the exact fault indicators, labelling, and even the display format differ between them and across firmware updates. Rather than listing individual indicators that may not match your specific unit, this guide explains the underlying categories of faults so you understand what a technician is actually diagnosing when they read your boiler's fault history.
Always confirm the exact meaning of what your display is showing against the printed manual or documentation for your specific model, since relying on a generic list found online can lead to the wrong assumption about what is actually wrong.
One of the most common fault categories covers ignition failure, where the boiler attempts to establish a flame but the flame sensor cannot confirm it within the expected window. This can stem from a fouled or misaligned flame sensor, a weak or improperly grounded igniter, gas supply issues, or a fault in the ignition control board itself.
A related but distinct category is flame loss during operation, where the boiler successfully ignites but the flame sensor loses signal partway through the burn cycle. This often points toward a draft issue disturbing the flame, a fouled sensor, or a gas pressure fluctuation rather than a complete ignition failure.
Venting or exhaust faults indicate the boiler has detected a restriction or blockage in the intake or exhaust venting, which can be caused by debris, ice buildup on an exterior vent termination during a cold snap, or a mechanical fault in the inducer fan. Given how many HTP installations in the region vent through exterior walls exposed to Metro Vancouver's wet winters, checking the vent terminations for obstruction is a reasonable first step before assuming an internal fault.
Flow faults relate to water circulation, either insufficient flow detected through the heat exchanger or a pressure reading outside the expected range, and are often connected to circulator pump issues, closed valves, or the system pressure problems described elsewhere. Over-temperature faults mean the boiler detected water or flue temperatures above a safe threshold and shut down protectively, which can stem from restricted flow, a failed temperature sensor, or scale buildup inside the heat exchanger.
Sensor fault indicators mean the control board is receiving a signal outside the expected range from a temperature, pressure, or flame sensor, which can mean the sensor itself has failed, its wiring has degraded, or it is reporting a genuinely abnormal condition elsewhere in the system. A technician needs to determine which of those it is rather than simply replacing the sensor.
| Fault category | What it generally indicates | Common underlying cause |
|---|---|---|
| Ignition failure | Flame not confirmed on start attempt | Fouled sensor, weak igniter, gas supply issue |
| Flame loss during operation | Flame sensor loses signal mid-cycle | Draft disturbance, fouled sensor, pressure fluctuation |
| Venting or exhaust | Restriction detected in intake or exhaust | Blocked vent termination, inducer fan fault |
| Flow or pressure | Water circulation outside expected range | Pump issue, closed valve, low system pressure |
| Over-temperature | Water or flue temperature above safe threshold | Restricted flow, scale buildup, sensor fault |
| Sensor fault | Signal outside expected range | Failed sensor, degraded wiring, or real fault elsewhere |
Note what the display shows exactly, whether it flashes, and whether the boiler attempts to restart on its own or stays fully locked out, since this history is useful to a technician. A single reset after a fault is generally reasonable, but repeated resets without understanding the cause can mask a developing problem and, in ignition or flame-related faults, is not something to keep doing on your own.
Diagnosing the underlying cause of any fault indicator, beyond checking for an obvious vent obstruction, should be left to a Technical Safety BC licensed gas fitter who can test the actual components involved rather than guessing from the display alone.
Safety note
If a fault is accompanied by a gas smell, a burning odour, soot, or symptoms like headaches and drowsiness near the appliance, leave the home immediately and call FortisBC at 1-800-663-9911 from a safe location. Do not repeatedly reset a boiler that keeps locking out; diagnosis of ignition, flame, or venting faults must be carried out by a Technical Safety BC licensed gas fitter.
HTP's product lines and firmware versions display faults differently, so a generic list found online can be misleading; always check the printed manual or documentation for your exact model.
A single reset is generally reasonable, but repeated resets without addressing the underlying cause can mask a developing ignition, flame, or venting problem and should be avoided.
Yes, debris or ice buildup on an exterior vent termination during a cold snap is a common cause of venting-related faults, and checking the termination for obstruction is a reasonable first step.
An ignition fault means the boiler could not confirm a flame when it first attempted to fire, while a flame loss fault means it ignited successfully but lost the flame signal partway through the burn cycle.
Yes, a sensor fault can mean the sensor has failed, its wiring has degraded, or it is correctly reporting a genuinely abnormal condition elsewhere in the system, which is why a technician needs to test rather than assume.
No, over-temperature faults can stem from restricted flow, scale buildup, or a failed sensor, and identifying which one requires testing that should be left to a licensed technician.
Family-run, TSBC-licensed (gas LGA0043870 · boiler LBP0046450), serving Metro Vancouver homes since 1999. Residential, natural gas only.
Call (604) 359-1081 Email info@canroheat.ca“Canro does an amazing job! Super professional and skilled with everything—boilers, furnaces, and AC. Always a pleasure working with them!”
“Five stars for Canro. We needed a replacement of a 30-year-old boiler. A new high-efficiency unit was installed—clean, professional work.”
“I can’t speak highly enough about George, who was recommended for a boiler service call for my parents’ home. George is excellent.”
25+ years keeping Metro Vancouver homes comfortable. Honest advice, upfront pricing, work that lasts.