Lennox Boiler: No hot water
If your Lennox combi runs the heating but delivers little or no hot water, the boiler is either failing to fire on a hot-water demand, not sensing enough flow through the plate heat exchanger, or reading the wrong temperature. The fault code narrows down which.
If your Lennox combi runs the heating but delivers little or no hot water, the boiler is either failing to fire on a hot-water demand, not sensing enough flow through the plate heat exchanger, or reading the wrong temperature. The fault code narrows down which. On Lennox boilers, this is linked to 3 fault codes (Ignition Lockout, Flame Failure, Sensor Fault). Below are the likely causes, the safe checks you can make, and exactly what our licensed BC gas technicians do — because boiler repair in British Columbia is licensed gas work, not a DIY job.
This is a gas-safety fault. Diagnosing ignition, flame, gas or venting problems requires combustion analysis and gas-pressure testing that, by BC law, only a licensed gas technician may perform. Never bypass a safety lockout. Smell gas? Leave the building and call 911 or FortisBC at 1-800-663-9911 from outside.
What you might notice
- No heat or no hot water
- Boiler attempts to fire (you may hear clicking) then locks out
- Repeated lockouts after a few ignition attempts
- Boiler fires briefly then shuts down
- Intermittent heat or hot water
- Short-cycling with lockouts
Safe checks you can make first
These are the only steps a homeowner should take. If they don’t resolve it, stop — the rest is licensed gas work.
- 1Confirm more than one hot tap is affected (rules out a single fixture)
- 2Check that mains water pressure to the home is normal
- 3Note whether the boiler fires when you open a hot tap
- 4Look for a fault code on the display
- 5Avoid repeated resets — a recurring fault needs a technician
Related Lennox fault codes
These Lennox codes are commonly behind “no hot water”. Tap any code for its full meaning, causes and fix.
What our licensed technicians do
- Verify incoming gas supply and lock-up/working gas pressure with a manometer
- Inspect and clean the igniter and flame-sensing electrode, checking the spark gap
- Test the gas valve operation and ignition control sequence
- Run a full combustion analysis to confirm a safe, clean flame after repair
- Measure flame-rectification current (microamps) during firing
- Clean or replace the flame-sensing electrode and check its ground path
Lennox no hot water — FAQ
Why does my Lennox combi boiler have heat but no hot water?
If your Lennox combi runs the heating but delivers little or no hot water, the boiler is either failing to fire on a hot-water demand, not sensing enough flow through the plate heat exchanger, or reading the wrong temperature. The fault code narrows down which. The related Lennox fault codes are Ignition Lockout, Flame Failure, Sensor Fault. A licensed technician confirms the true root cause with the right instruments before any repair.
Is it safe to keep resetting my Lennox boiler when it shows "no hot water"?
No. A single reset after a one-off event is fine, but "no hot water" involves gas, ignition, flame or venting safety. Repeated resets without fixing the cause can be dangerous and can damage the boiler. If the fault returns, switch the boiler off and call GasBoilers.ca at 604-359-1081. If you ever smell gas, leave the building and call 911 or FortisBC at 1-800-663-9911 from outside.
Can you repair a Lennox boiler with this problem in Greater Vancouver?
Yes. Our Red Seal–certified, TSBC gas-licensed technicians diagnose and repair Lennox GWB8-IH gas-fired hot water boilers across Vancouver, Burnaby, Surrey, Richmond, the Tri-Cities and the rest of Greater Vancouver. Same-day appointments are often available — call 604-359-1081.
“No hot water” on other boiler brands
Lennox boiler no hot water? We can help today.
Licensed, Red Seal–certified gas technicians across Greater Vancouver. Upfront pricing, same-day service available.