Do we need a new boiler?

[Keggo123]

Mum has a Glow worm 100e boiler which is playing up. The firm she called in to check it out have advised her to get rid and have a new one? She is thinking they may be pushing for a bigger job.... possibly?

Boiler works for heating as normal but on hot water cuts out all the time.
Before this she complained the water temperature fluctuated a lot. From reading other posts on here that points to the Plate heat exchanger - which the plumber did say was the problem... he said would be about £200 to replace. Further he said the burner modulation was not working on the DHW. New main control card didnt rectify this and to his credit he put the old one back and didnt charge her. Not sure how he tests the nodulation if the heat exchanger is not working / blocked??

Given a new boiler would be approx £700 + fitting. Poss £1500+ should we replace this 9 year old boiler or call glow worm to repair the old one and get her on th British Gas homecare scheme or similar?? What would an experienced head do???

 

[BingoBongo]

get someone else to have a look,might just be the thermistor or hw microswitch or the divertor.

run the hw and see if the closest rad to the boiler starts to heat but if its not modulating it could just be the thermistor

 

[Agile]

The plate HE can be cleaned on site, messy but cheaper than replacement.

If its not modulating and not caused by the PCB then it could be just a gas valve setting adjustment or a sensor fault.

These are not the most reliable of boilers but still repairable.

Tony

 

[Keggo123]

Thanks Tony,
Got a gas Safe guy coming out this week... worried Mum's lack on know how will leave her wide open to them bigging up the job though. Fingers crossed.
heating works fine, just no hot water. Luckily she has an additional shower room with an electric shower so she has been happy enough ths far.

Keggo

 

[YELLERBELLY]

if the plate heat ex is full of dirt then the boiler won't modulate because the heat ex thermistor is constantly calling for heat

 

[Rob]

if the plate heat ex is full of dirt then the boiler won't modulate because the heat ex thermistor is constantly calling for heat

Exactly. Boilers arent designed to cope with a blockage in the plate. The HW isnt very hot so the burner keeps chucking out the power. All the power produced cant be lossed, due do blockage, so the primary thermistor quickly goes outside limits and the boiler shuts down. Eventually cools and cycle repeats.

Im assuming this is a compact 100e. Which has it faults but isn't the worst of boilers and for £200 is well worth repairing.

 

[Keggo123]

Will be the 2nd time its been changed!

 

[DP]

Will be the 2nd time its been changed!

If that is the case, getting the system cleaned will fix that.

 

[Tipper]

Hard water area?