Potterton [E128] fault codewhat it means and how to fix it

This is the digital-display generation's code for a flame that was established and then lost, as distinct from one that never lit. The Assure System and Promax Ultra installation manuals separate the two in the same paragraph: 133, 134 and 135 cover a gas supply that was interrupted, an ignition that failed or a flame that was never detected, while 128 is reserved for a flame that was lost once the boiler was already running normally.

The table entry is simply "Flame failure", it carries the R symbol, and it is on both manuals' list of codes that a one-to-three-second press of the Reset button will clear. It is not on the older Promax and Titanium tables; those boilers report a lost flame as E133 whatever stage it happened at, so an owner used to a Promax will not have seen this number before. The fault-finding chart in the Assure System manual reaches 128 at the step "Burner goes out after 5 seconds" and sends the engineer to section G, which is the flame-sensing side: electrode condition, its connection, and the earth.

If the burner lit and ran for minutes before dropping out, the causes move to the gas supply (pressure falling under load, a regulator on its way out), the flue (recirculation on a windy day), or a condensate pipe that is filling up faster than it drains.

1. 1

   Check other gas appliances still work, and in cold weather check any external condensate pipe for ice.

2. 2

   Press Reset for about one second. Holding it longer than two seconds will not reset an Assure, according to its user guide.

3. 3

   If 128 comes back within the day, note the time and what the weather was doing, and contact your installer or Baxi Customer Support. Do not keep resetting it.