Glow-worm Energysaver Combi 2 100

[Agile]

Is anyone very familiar with this rather difficult to work on model?

The symptoms are that its fine on DHW.

On CH the fan revs up and dies every few seconds. It does not power the diverter to drive it to the CH position. The motor seems to be failed in the DHW position.

If I manually move the diverter valve to the CH position it works OK.

I would guess both the PCB and actuator have failed ?

Without the MI and with wiring which changes colour/number behind the gas valve and a PCB which is not accessible in situ I dont see this model as very suitable for a diagnostic engineer, only a parts changer!

Tony

 

[ChrisR]

You do have the MI.
Also on the GW site.
Not that they tell you anything very useful with regard to your problem as far as I can see.
Is it at the 220 ohm resistor that the wiring changes colour (r to r/wh?)?

What's the resistance of the DV motor?

 

[Agile]

I did not have the MI when I was in front of the boiler last night. The owner gave me a dongle with the MI on it but this is not being read by this computer so needs software download! Have got MI from GW site now!

As part of the "make it difficult", the connections to the DV motor are not accessable to test when its on the valve!

I could only remove the head or the plug. However its not being powered by the PCB to drive it to the CH position so even if it worked it would not!

Connecting the supply to the CH position with the head off seems to do nothing but with the head removed the lever moves so its not immediately obvious so far if its faulty or not. I was short of time and had no wire link with me and it was for the moment irrelevent in view of the lack of PCB driving it.

There are about FIVE wires of different colours all paralleled behind the gas valve and the PCB cannot be withdrawn for testing while its operational.

What a mad design !!!!

There seem to be two apparent faults, not driving the DV in CH and the regular reving up of the fan although this may stop after the CH system is up to temp.

Update, Owner has just called to say it came on for CH during the night but delayed DHW reheat after store was used up.

That last fact MIGHT be a clue! Suppose boiler had thought store was cold then it would give priority to reheating it and would not give any CH !!!

I think I will be looking at the sensors on the store first !!!

Tony

 

[ChrisR]

LOvely.
File with Bahama, Envoy, Minimiser, French....

 

[gasgeezer]

Have worked on two these in the past both not letting c/h work but different faults.First was the dhw store thermistor faulty.Second was known as dripping tap syndrome(COMMON ON THESE BOILERS)the boiler senses dhw movement and so prevents c/h from coming on.Either turn off dhw on boiler, or isolate dhw valve if boiler fires up on c/h you have a small leak or dripping tap somewhere.Agree horrible to work on usually try to steer clear of them