E-14 is a disturbance on the low voltage side of the system. This is separated into two parts.
1) The unit resets and begins to work. E 14 returns in an un-predictable time frame.
2) Does the unit reset, but goes to E 14 with-in 5 seconds.
1) This often is caused by the dry contact in the aqua-stat in the domestic water heater. The dry contact water heater’s aqua-stat should be replaced with a PSRKIT-22 Triangle Tube IDHS. This will now allow the boiler to see the actual temperature in the tank and determining when to go into water heating operation.
2) This disturbance is far more difficult to pinpoint. It is important to be sure that the reset is working. When the reset button is pressed and released, the E-14 should disappear, and a software code show up, once that clears, the E-14 will re-appear we now know the reset works. Remove the entire field wires connected to terminals 7 through 19. Try to reset the boiler. If the E14 goes away, one by one re-install the field to see what field device is affecting the boiler. Remove the X04 plug from the MCBA module. (This is the plug with 2 blue wires and 1 yellow wire. Be sure to look carefully how the plug is connected and when re-connecting it, be sure to put it back the same way you removed it.) Reset the boiler, if the E-14 goes away and is replaced with a b-40 and a 9-## reconnect the X04, if it immediately goes to E14. We now have isolated the fault.
Since the E14 stopped when the X04 was removed and now is back in place. Remove the 2 yellow wires from the flue sensor, reset the boiler. If the b-40 and 9## returns, replace the flue sensor. If the E-14 comes right back, replace the wires on the flue sensor, then remove the wires in the top of terminals 17 and 18 (one has a blue and a yellow wire in it, the other has a single blue) let them hang in the air, reset the boiler. If the fault clears, isolate and insulate each of the wires. They are not being used, so they may remain isolated and insulated
If the E-14 does not disappear when the X04 is removed remove the X05 plug. Then reset the boiler, if the boiler resets and shows the b40 and the 9##, then replace the X04, reset the boiler and operation should commence. This is an indication that there is a problem with the outdoor sensor or the wire for the outdoor sensor.