HTP Boiler Error Codes — Meanings, Causes & Repair in Greater Vancouver

Seeing a fault code on your HTP boiler? This guide explains what the most common HTP boiler error codes mean, what’s safe to check yourself, and when to call HeatLand’s licensed, TSBC-certified gas technicians for HTP boiler repair across Metro Vancouver and the Fraser Valley.

The codes below apply across common HTP models (UFT, UFTC, Elite FT, Pioneer). Meanings follow HTP’s documented fault codes — always confirm against your unit’s own manual, because exact wording can vary by model, control board and firmware.

How to read HTP boiler error codes

HTP (Heat Transfer Products) uses different display formats depending on the boiler platform/control. (1) MOST current HTP condensing/combi boilers — the UFT and UFTC series and the Elite FT (EFT / EFTC) series — use the SMART System control, which shows a flashing 'Er:XX' numeric code on the front display (e.g. Er:10, Er:11, Er:16). These boilers distinguish a SOFT lockout (the control auto-recovers once the condition clears, e.g. an overheat that cools down) from a HARD lockout (a safety-significant fault such as flame, ignition, or condensate, which stays locked until the Power button is pressed). To clear a hard-lockout Er:XX code you press the Power button once. (2) Older Pioneer PHR/PHC models use multi-character alphanumeric codes (e.g. F00, E19, FLU, Fou, LEO) where 'F'-prefix Fault codes lock out and the others are non-locking Error codes. (3) Newer Giannoni-platform models (Elite Ultra, Elite Premier / ELP) use a different scheme ('1 0X' blocking/warning codes, or 'A0X' lockout codes). This reference focuses on the Er:XX codes used by the UFT / UFTC / Elite FT families, which are the most common HTP units installed in Canada/North America. Always confirm the exact code against the manual for the specific model.

HTP boiler error codes & what they mean

These are the HTP boiler codes our Greater Vancouver technicians see most. Anything marked pro repair involves gas, electrical, sealed-combustion or control-board work that must be done by a licensed gas technician (TSBC-certified in BC) — never open gas or electrical components yourself.

Code	What it usually means	Common causes	Safe to check yourself
Er:10	Flame loss — the flame extinguished the maximum allowed number of times in a row (typically 8 times on UFT-80W, 5 times on some models). Hard lockout pro repair	Low or fluctuating gas supply pressure; Dirty or weak flame-detection (rectifier) sensor; Air in the gas line after service	Confirm the gas shutoff valve to the boiler is open; Confirm other gas appliances in the home work (so gas is supplied); Check that the condensate drain/trap line is not clogged or frozen
Er:11	Ignition failure — the boiler failed to establish flame after the maximum number of ignition attempts (typically 10 times on UFT-80W, 5 times on some models). Hard lockout pro repair	Gas off, low gas pressure, or air in the gas line; Dirty/worn spark igniter or incorrect electrode gap; Failed igniter transformer or ignition wiring fault	Confirm the gas shutoff valve to the boiler is open; Confirm other gas appliances in the home are working; Press the Power button once to attempt a restart
Er:16	Operating (CH) temperature sensor detects water temperature greater than 203°F (95°C) — overheat of the heating water. The pump runs to cool the boiler; the code clears once CH temperature drops (auto-recovering / soft on most models) pro repair	Circulator not running or air-bound system (poor flow); Closed isolation valves / blocked CH inlet restricting flow; Low system water pressure	Check the system pressure gauge reads within the normal range (typically about 12–20 psi cold); Confirm heating-system isolation valves are open; Allow the boiler to cool; the code may clear on its own once temperature drops
Er:20	Condensate fault — the condensate switch is open when it should be closed (condensate drain trap full/blocked). Hard lockout pro repair	Clogged or frozen condensate trap/line; Condensate hose disconnected, kinked, or in poor condition; Blocked exhaust vent backing up condensate	Check the condensate drain line and trap for clogs, kinks, or freezing; Confirm the condensate line drains freely to its termination; Press the Power button once after clearing any obvious blockage
Er:28	Overheat sensor open or short — the dedicated overheat/high-limit sensor circuit is faulty pro repair	Loose or corroded overheat-sensor connector; Damaged sensor wiring; Failed overheat sensor	Press the Power button once to see if the fault clears; Note the code and arrange service — this is an internal sensor fault
Er:29	Air Pressure Switch (APS) open — the combustion air pressure switch is not closing during the run cycle. Hard lockout pro repair	Blocked intake or exhaust vent / blocked condensate line; Failed APS switch or disconnected pressure tubing; Fan/blower not building proper pressure	Check the outside intake and exhaust vent terminations for blockage (snow, ice, debris, nests); Check the condensate line is clear; Press the Power button once to restart after clearing any blockage
Er:30	DHW storage temperature sensor open or short — the indirect/storage tank temperature sensor circuit is faulty pro repair	Loose or corroded storage-sensor connector; Damaged sensor wiring; Failed storage temperature sensor	Note the code; this is an internal sensor fault that needs a technician; Heating may still operate even if hot-water storage control is affected
Er:32	DHW (domestic hot water) sensor open or short — the DHW outlet temperature sensor circuit is faulty pro repair	Loose or corroded DHW-sensor connector; Damaged sensor wiring; Failed DHW outlet temperature sensor	Note the code; this is an internal sensor fault that needs a technician
Er:33	CH (central heating) temperature sensor open or short — the heating supply temperature sensor circuit is faulty pro repair	Loose or corroded CH-sensor connector; Damaged sensor wiring; Failed CH temperature sensor	Note the code; this is an internal sensor fault that needs a technician
Er:35	Exhaust (flue) temperature sensor open or short — the exhaust gas temperature sensor circuit is faulty pro repair	Loose or corroded exhaust-sensor connector; Damaged sensor wiring; Failed exhaust temperature sensor	Note the code; this is an internal sensor fault that needs a technician
Er:36	System (loop) sensor short — the optional system/loop temperature sensor circuit is shorted. (Some manuals list a related 'System Sensor Short' fault.) pro repair	Shorted or damaged system-sensor wiring; Failed system/loop temperature sensor	Note the code; this is an internal sensor fault that needs a technician
Er:37	Abnormal supply (line) frequency — the incoming AC line frequency is out of range. Non-locking; clears automatically when the supply frequency returns to normal pro repair	Unstable utility power or generator/inverter supply with off-spec frequency; Wiring/grounding issue affecting the line-frequency reading	Confirm the boiler is on stable utility power (not a generator with unstable output); The code should clear on its own once power stabilizes
Er:38	Control stores data but data is not saved — the main control could not write/verify its stored parameters; main control (PCB) typically requires replacement pro repair	Internal main-control (PCB) memory fault	Note the code; this is an internal control-board fault and requires a technician
Er:40	Gas leakage detected — gas leakage detected for greater than 5 seconds, or three times within 10 minutes. Lockout; requires inspection of gas connections pro repair	Gas valve or gas-train leak / loose gas connection; Faulty gas valve or gas-leak detection circuit	If you smell gas, leave the building and call your gas utility / emergency line — do not attempt checks yourself; Do not reset repeatedly; have a licensed technician inspect immediately
Er:41	Fan speed too high with flame on — the blower is running faster than commanded while the burner is firing. Lockout pro repair	Venting restriction or sensing/feedback issue; Burner or fan fault; Failed blower/fan	Check vent terminations for blockage; Note the code and arrange service
Er:42	Low Water Cutoff (LWC) circuit is open / jumper wire disconnected — the LWC safety circuit is not closed. Lockout pro repair	Low water level tripping an external LWC device; Missing/disconnected LWC jumper when no LWC is installed; LWC wiring fault	Check the system pressure gauge — very low pressure can indicate low water; Note the code; verifying the LWC circuit is a technician task
Er:43	Burner overheat switch open — the burner-plate over-temperature limit switch (opens around 392°F / 200°C) has opened. Lockout pro repair	Overheating at the burner plate; Loose switch connection; Failed burner overheat switch	Allow the boiler to cool fully; Note the code; this safety switch fault requires a technician
Er:61	Fan speed feedback signal abnormal — the control is not getting a valid speed signal back from the blower. Non-locking; clears when the condition is remedied pro repair	Loose fan/blower wiring or connector; Failed blower/fan motor; Power-supply issue to the fan	Note the code and arrange service — the fan/blower circuit is an internal component
Er:66	Mixing valve initial-value error — the internal mixing valve cannot return to its initial (home) position (combi/integrated DHW models) pro repair	Mixing valve actuator stuck or obstructed; Mixing valve wiring/connector fault; Failed mixing valve motor	Note the code; the mixing valve is an internal component requiring a technician
Er:68	Mixing valve operation error — the internal mixing valve is stuck in its initial position and will not move (combi/integrated DHW models) pro repair	Mixing valve actuator seized or obstructed; Mixing valve wiring/connector fault; Failed mixing valve motor	Note the code; the mixing valve is an internal component requiring a technician
Er:70	Control self-check failure — register/RAM/ROM/I/O port/AD abnormal, or important EPROM data / safe data abnormal (internal control fault). Often clears after a power cycle; persistent occurrence means control replacement pro repair	Internal main-control (PCB) fault or corrupted stored data; Electrical noise/transient affecting the control	Note the code; if it persists after power is cycled it is an internal control fault for a technician
Er:72	Flame signal detected before ignition — the control senses flame (or false flame) when none should be present. Non-locking; requires inspection pro repair	External light reaching the flame sensor (e.g. boiler cover off / open chamber); Faulty flame-detection sensor or wiring; Gas valve leaking by / residual flame	Confirm the boiler front cover is fully in place and secure; Note the code and arrange service if it persists
Er:76	Poor communication — communication error between the main control and the display panel. Non-locking; clears when the condition is remedied pro repair	Loose/damaged ribbon or harness between control and display; Electrical noise/interference; Failed display or main control	Note the code; the control-to-display link is internal and requires a technician
Er:78	Cascade communication error — communication fault between boilers in a cascaded (multi-boiler) installation. Non-locking; cascaded systems only pro repair	Damaged or disconnected cascade communication cable; Incorrect boiler addressing in the cascade; Failed control on a cascaded unit	Applies only to multi-boiler (cascade) systems; note the code and arrange service
Er:80	Low water level — the water-level detection sensor detected low water (typically four times), interrupting operation to prevent dry-firing pro repair	Low system water pressure / loss of water; Air not fully purged from the system; Low-water-level sensor wiring fault or failed sensor	Check the system pressure gauge — low pressure can indicate low water; Look for visible leaks around the boiler and piping; Note the code; refilling/bleeding and sensor checks should be done by a technician
Er:81	Low water level circuit error — a fault in the low-water-level detection circuit pro repair	Low-water-level sensor wiring or connector fault; Failed low-water-level sensor	Note the code; this is an internal sensor-circuit fault for a technician
Er:85	Freeze protection — the control detected water temperature below about 33°F (freezing-risk condition) and displays this code while freeze protection runs pro repair	Very low ambient/water temperature near the boiler; Loss of heat to the boiler space in cold weather	Confirm the area around the boiler is not exposed to freezing temperatures; The code clears once the freezing condition is remedied
Er:94	Vent (exhaust) over-temperature — the vent/exhaust temperature was detected too high. Safety shutdown pro repair	Heat exchanger fouling/scaling raising flue temperature; Venting restriction; Exhaust temperature sensor fault	Check vent terminations for blockage; Note the code and arrange service — high flue temperature needs a technician

HTP boiler codes we get called for most

Er:11 — Ignition failure — the boiler failed to establish flame after the maximum number of ignition attempts (typically 10 times on UFT-80W, 5 times on some models). Hard lockout

Typical causes include gas off, low gas pressure, or air in the gas line; dirty/worn spark igniter or incorrect electrode gap; failed igniter transformer or ignition wiring fault. A few things are safe to check yourself (Confirm the gas shutoff valve to the boiler is open; Confirm other gas appliances in the home are working), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes Er:11 on HTP boilers throughout Greater Vancouver.

Er:10 — Flame loss — the flame extinguished the maximum allowed number of times in a row (typically 8 times on UFT-80W, 5 times on some models). Hard lockout

Typical causes include low or fluctuating gas supply pressure; dirty or weak flame-detection (rectifier) sensor; air in the gas line after service. A few things are safe to check yourself (Confirm the gas shutoff valve to the boiler is open; Confirm other gas appliances in the home work (so gas is supplied)), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes Er:10 on HTP boilers throughout Greater Vancouver.

Er:29 — Air Pressure Switch (APS) open — the combustion air pressure switch is not closing during the run cycle. Hard lockout

Typical causes include blocked intake or exhaust vent / blocked condensate line; failed aps switch or disconnected pressure tubing; fan/blower not building proper pressure. A few things are safe to check yourself (Check the outside intake and exhaust vent terminations for blockage (snow, ice, debris, nests); Check the condensate line is clear), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes Er:29 on HTP boilers throughout Greater Vancouver.

Er:16 — Operating (CH) temperature sensor detects water temperature greater than 203°F (95°C) — overheat of the heating water. The pump runs to cool the boiler; the code clears once CH temperature drops (auto-recovering / soft on most models)

Typical causes include circulator not running or air-bound system (poor flow); closed isolation valves / blocked ch inlet restricting flow; low system water pressure. A few things are safe to check yourself (Check the system pressure gauge reads within the normal range (typically about 12–20 psi cold); Confirm heating-system isolation valves are open), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes Er:16 on HTP boilers throughout Greater Vancouver.

Is it safe to keep running a HTP boiler with a fault code?

Most HTP fault codes put the boiler into a safe lockout for a reason. You can safely check the basics — gas supply on, power on, the thermostat calling for heat, system pressure in the normal range, and the condensate drain not frozen or blocked (a common cause in Vancouver cold snaps) — and restart it once. If the code returns, stop and book a technician. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911.

HTP boiler repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair HTP boilers — ignition faults, flame and sensor errors, low-pressure and pump problems, fan and flue faults, and control-board issues — including units we didn’t install. We’re brand-agnostic, carry common parts, and give you an honest repair-or-replace assessment with upfront pricing and a free estimate. If your boiler is beyond economical repair, we’ll show you right-sized, high-efficiency replacement options and the rebates available.

Need it sorted fast? We offer priority emergency boiler repair. Explore Boiler services, browse all boiler error codes by brand, or request a free estimate.

HTP boiler service areas

We repair HTP boilers across Greater Vancouver and the Fraser Valley, including:

HTP boiler error code FAQs

Can I reset my HTP boiler myself?

Yes — power-cycling the reset button once is generally safe after you’ve checked the basics (gas supply on, power on, the thermostat calling for heat, system pressure in the normal range, and the condensate drain not frozen or blocked (a common cause in Vancouver cold snaps)). If the boiler faults again right away, stop and note the code — repeatedly resetting a boiler that keeps locking out can mask a real problem. Call a licensed, TSBC-certified gas technician to diagnose it.

What does the HTP Er:10 code mean?

On HTP boilers, Er:10 commonly indicates flame loss — the flame extinguished the maximum allowed number of times in a row (typically 8 times on uft-80w, 5 times on some models). hard lockout. Confirm the exact meaning against your unit’s manual — codes can vary by model and series — and have the repair done by a licensed, TSBC-certified gas technician. HeatLand fixes this across Greater Vancouver.

Do you repair HTP boilers you didn’t install?

Yes. HeatLand is brand-agnostic and services HTP boilers throughout Metro Vancouver and the Fraser Valley, whether or not we installed the unit. We carry common parts and give you an honest repair-or-replace assessment.

Is a HTP boiler fault code an emergency?

No heat in cold weather is worth treating urgently. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911. For priority boiler repair across Greater Vancouver, call (604) 330-3812.

How much does HTP boiler repair cost in Vancouver?

It depends on the fault. Many HTP codes point to sensors, ignition or pump parts — usually far cheaper than replacement. We give upfront pricing and a free estimate before any work.

More Boiler error-code guides

HeatLand repairs every major boiler brand across Greater Vancouver. More brand guides: