56
EcoBlue Heat
7219717 - 02 (08/15)
1
Introduction
10.3.15 PCB
(Figs. 53i & 53j)
Before changing the PCB it is essential that a
resistance check is performed on the gas valve to
eliminate the possibility that the valveis faulty and
causing PCB failure.
Disconnect the electrical plug from the gas and check
resistance between:-
Pins 3 & 1 - should be approximately 6.5K ohms
Pins 3 & 4 - should be approximately 890 ohms
(Pin 1 is the uppermost)
If values differ significantly replace the gas valve.
A Phillips PH-1 screwdriver is required.
T20 Torx key & ESD wrist strap are supplied.
Remove the ducts as described in Section 10.3.4
1. Disconnect the cable from the bottom of the PCB and break
the mains power cable connection at the right hand side of the
housing.
2. Disengage the fan protective cover tab and lower the cover
slightly and remove the “Socket & See” electrical test point cable
from its PCB edge connection. Slide the “Socket & See” electrical
test point from its location and lower the cover fully.
3. Wearing the ESD wrist strap, disconnect the electrode lead,
earth lead and the main sensor harness from the PCB, taking
care not to touch any of the PCB components.
4. Disconnect the electrical plug from the gas valve and remove
the screws securing the fan driver PCB to the fan motor (Fig. 53i).
Note the 2 locating pins that align the PCB (Fig. 53j). Push the
retaining clip to the right and disengage the fan driver PCB.
Fan driver PCB is permanently wired to the main PCB.
5. Undo the screws securing the main PCB to the fan (Fig. 53i)
and remove it, including the fan driver PCB.
6. Reassemble with the new PCB in reverse order of dismantling,
checking all joints tight and wires are secure..
7. When connecting the fan driver PCB to the fan use the locating
pins to align it, and do not force the connection. Ease the
retaining clip to the right to aid assembly. Ensure that the wires
connecting the fan driver PCB to the main PCB do not touch the
cover.
8. Reinstate the gas and electrical supplies and recommission the
boiler.
Fan Driver
PCB Screws
Main PCB
Screws
Locating
Pins
Retaining
Clip
Fig. 53i
Fig. 53j