Vaillant

Vaillant Ecomax Range

 

Vaillaint Ecomax 824e Vaillant Ecomax 828e

Problem Solution
F20, F22, F23, F24

This is when the reading between the flow and return thermistors are outside the expected range, May be sticking pump, main heat exchanger partially blocked,

Check black rubber hoses, these can be a bottleneck for magnatite, they block up
 

 

Vaillant Ecotec Plus

 

Problem Solution
Circulation Problems

Check black rubber hoses if fitted, these can block and be a bottleneck for magnatite
Blank Display Unplug all components going to PCB leaving just L,N&E connected, then reconnect one by one in turn reinstating power to see if display returns. This should enable you to find which component is causing the issue. Normally the low pressure sensor is the cause
Blowing fuses on PCB

disconnect all plugs from PCB, and fit new fuse,reconnect plugs one by one untl faulty circuit has been found
F75

check pump operation

check low pressure

double check pressure sensor voltage is correct, approx 1.6VdC at PCB on 9 and 12 on X2 (black and green wires)

check expansion vessel charge
F20, F22, F23, F24

This is when the reading between the flow and return is outside the expected range, May be sticking pump, main heat exchanger partially blocked,

Check black rubber hoses, these can be a bottleneck for magnatite, they block up
 

Vaillant VCW GB 221/242/282

 

Problem Solution
Overheat/no central heating

check servo valve has returned to its rest position, and spindle/valve is not stuck in water position
Hybrid/Non Hybrid PCB identification Pull thermostat knob off spindle and check, white plastic = hybrid PCB, anything else = non hybrid PCB
Low fire only

Check diaphragm pump tubes for kinks/splits. Check minimum maximum pressures set up correctly
Hot water cycling on/off

Check plate heat exchanger for restrictions/sludge/scale, if secondary heat exchanger conversion kit has been fitted, a link on PCB and disc in diverter may not have been updated. Some diverter valves let-by some water to keep the domestic heat exchangers warm, this is ok for the plastic exchangers but can cause problems with the newer metal exchangers. A solid disk is included in update kit to prevent let-by and scale formation