Lochinvar Outlet High Limit: Outlet High-Limit / Over-Temperature
What the Lochinvar Outlet High Limit fault means, what causes it, and why it's a job for a licensed BC gas technician — not a DIY reset.
Severity
High — needs prompt professional attention
What the Lochinvar Outlet High Limit fault means
Outlet water temperature exceeded the high-limit and the boiler tripped overheat protection.
On Lochinvar Knight, WHN and SMART System series, Outlet High Limit is a over-temperature / high-limit. It is a protective response — the boiler is telling you something needs attention, and the safe, lasting fix is a proper diagnosis rather than repeated resets.
Symptoms you may notice
- Boiler locks out under load
- Hot or burning smell near the unit
- Heat that starts then cuts out
Common causes of Lochinvar Outlet High Limit
Why this is not a DIY fix
An overheat lockout is a protective trip — the boiler is telling you heat is not moving away from the heat exchanger fast enough. Running it repeatedly risks cracking the heat exchanger (an expensive, sometimes total-loss failure). The root cause (circulation, blockage, or a failed sensor) must be found by a technician before the unit is returned to service.
In British Columbia, gas work must be performed by a TSBC-licensed gas fitter. GasBoilers.ca — a CanroHeat division — sends Red Seal–certified, gas-licensed technicians who diagnose the true cause, repair it correctly, and verify safe operation before they leave.
How our technicians diagnose & repair it
- 1Check circulation: pump operation, air-bound zones, closed valves and flow rate
- 2Inspect the heat exchanger and strainer for blockage or scale
- 3Test the high-limit and supply/return temperature sensors
- 4Confirm correct system pressure and bleed trapped air
Related Lochinvar codes
Lochinvar Outlet High Limit — FAQ
What does the Lochinvar Outlet High Limit fault mean?
Outlet water temperature exceeded the high-limit and the boiler tripped overheat protection. On Lochinvar Knight, WHN and SMART System series, this is categorised as a over-temperature / high-limit.
What causes Lochinvar Outlet High Limit?
The most common causes are: Poor circulation; Pump fault; Blockage; Sensor fault. A licensed technician confirms which one applies before any part is replaced.
Can I fix Lochinvar Outlet High Limit myself?
No. An overheat lockout is a protective trip — the boiler is telling you heat is not moving away from the heat exchanger fast enough. Running it repeatedly risks cracking the heat exchanger (an expensive, sometimes total-loss failure). The root cause (circulation, blockage, or a failed sensor) must be found by a technician before the unit is returned to service. Repeatedly resetting the boiler without fixing the root cause can be unsafe and can cause further damage. Call GasBoilers.ca at 604-359-1081 for a licensed diagnosis.
Is the Lochinvar Outlet High Limit fault dangerous?
This is a protective fault — the boiler has shut down a function to protect itself. It is best diagnosed promptly by a licensed technician so the underlying cause does not lead to a more expensive failure.
How much does it cost to fix Lochinvar Outlet High Limit in Greater Vancouver?
Cost depends on the root cause and any parts needed. We start with a flat-rate diagnostic, then quote the repair before any work begins — no surprises. Call 604-359-1081 for current pricing and same-day availability.
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