Alpha InTec 30C, 34C Error 25: Overheat lock out

Alpha InTec gas boiler · taken from the manufacturer’s manual, pages cited

Fault code25

The system has overheated and is locked out to prevent damage. The manual's first action is: “Air in heat exchanger Blocked or restricted primary flow Heat exchanger air flow blocked Flue restriction Flue sensor fault Pump fault Boiler or heating circuit valve closed”

Model
Alpha InTec 30C, 34C
Display shows
Overheat lock out (25)
Type
Fault code
Source
Manual p. 42

What 25 means

Overheat lock out p. 42

Common causes

  • Rapid temperature rise of flue sensor p. 42

What to do

  1. Air in heat exchanger Blocked or restricted primary flow Heat exchanger air flow blocked Flue restriction Flue sensor fault Pump fault Boiler or heating circuit valve closed p. 42

If 25 is still not resolved

The manual gives no further instruction for this code. Open the code table in the PDF or contact Alpha InTec service.

Open the manual at page 42 All 30C, 34C error codes Manual details & download

This page summarises what the manufacturer’s manual says about 25; each statement links to the page it comes from, and quoted lines are copied word for word. It is not a substitute for the manual or for a qualified installer. ManualLib is not affiliated with Alpha InTec. Found a mistake? Report an error.