worcester 400rsf highflow

[gmzx]

hi, can anyone shed some light on this problem, 400rsf highflow hot water overheating , this boiler has had new dh exchanger, new manifolds,pump,diverter, and primary heat exchanger, 3 new sets of thermostats all fitted by bg, problem they cant solve is this, when hot water is on heatbank emptys completely before the boiler fires up to re heat it, it then continues to heat the water untill the thermostat gose of the scale and the water is far too hot,this boiler used to fire up after about 30sec when hot water was called for,it no longer dose this, at my whits end with it as bg are saying they dont know what could be wrong with it, considering what they have already replaced on it, is it possable that the pcb could be faulty,,bg have tested this but say it ok, dont know what else prob could be,

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[nickso]

no reason why it can't be the pcb. the stats tell the pcb what is going on, if they are new then perhaps the pcb is using faulty logic to interpret this.

BG have no way of "testing" the pcb, all they can do is watch it's sequence of ops and check inputs and outputs, they can't really test anything on the board as such. seeing as it's sequence of ops seems to be wrong it's worth a go changing it and seeing what happens, it should prove the pcb in minutes by the sounds of it.

 

[Agile]

If BG cannot fix it then I think that you can ask them to call the manufacturers engineers under your agreement.

Whilst it does sound as if its the PCB my experience would usually be that they have missed something or pulled a wire out of a connector.

The boiler may look rather daunting but its really very simple how they work.

Tony

 

[boilerdoktor]

what happens if you turn the DHW knob right down to minimum. This should heat the heatbank to about 55 deg and then go off.

When the tap is run does the green demand button come on?

 

[gmzx]

have set the stat too min, water still hot, and a bubbling noise coming from boiler, have spoke to the guy from bg who was out at it and he say he replaced the driver board, stripped boiler down and rebuilt it to make sure there was no blokages , have told them that to me it feels as though the flow of water has slowed down and that the boiler should fire up when hot water is caled for, he say no the heatbank will empty first,to which i said it has never done this, if that be the case then it would take over 10 min to heat up everytime dhw was called for,which would end up costing a fortune, only 2 parts left to replace, flowswitch and presurevessel

 

[Agile]

You are of course quite right.

You can form your own conclusion about the BG guy !

Tony