Baxi [E.02.07] fault codewhat it means and how to fix it

Baxi's two newest display systems report low pressure in stages, and E.02.07 is the last of them. On the 200 and 400 Combi the sequence is H02 alternating with 06, "low water pressure in the heating circuit", a temporary fault that "will automatically reset once the cause of the fault has been resolved", and then E02 alternating with 07, the same fault as a permanent lockout that needs the RESET button. On the Combi 2 the stages are A.02.06 "low system pressure in heating circuit", with the boiler still running, then H.02.07 "low pressure in heating circuit (permanently)", and the manual's remedy for both is one line: "check the system pressure and restore it, check the pressure of the expansion vessel, check for any system/boiler leaks".

Baxi's Combi 2 quick guide gives the householder the same job in plainer words — "A.02.06 or H.02.07: boiler needs repressurising. All boilers need repressurising occasionally. It's a simple job you can do yourself" — and their repressurising how-to describes the filling loop and the target of 1 to 1.5 bar. The 200/400 user manual lists E02 07 under "low water pressure" and the installer table gives the causes as "water leak on boiler, water leak on system — check boiler, check system, repressurise system".

The point of the staged codes is the same as it was for E118 and E119 on the older Baxis: the sealed system has lost water, and the question is where it went. A top-up once a year is normal; a top-up every week is a leak or a flat expansion vessel, and the Combi 2 manual's mention of the vessel pressure is the clue that a boiler which needs frequent repressurising and occasionally weeps from its relief pipe wants an engineer rather than another turn of the filling loop.

1. 1

   Read the pressure on the display or gauge. Baxi's how-to gives the cold target as between 1 and 1.5 bar; below about 0.5 bar the boiler stops with this code.

2. 2

   Find the filling loop — a braided hose or a fixed key under the boiler — and open its valves slowly until the pressure reaches 1 to 1.5 bar, then close both. Baxi's repressurising guide and video walk through this.

3. 3

   Reset: RESET for one second on a Combi 2, at least three seconds on a 200 or 400 Combi. H.02.07 on a Combi 2 and H02 06 on a 200/400 clear on their own once the pressure is back.

   If you are repressurising more than a couple of times a year, or water drips from the copper pipe outside, stop topping up and call an engineer: the water is going somewhere.