Grant vortex combi boiler flow switch

[c.zakalwe]

Hi.
Im hoping cause the boiler is fairly popular someone might recognise this issue.
Recently discovered the flow switch on our grant Vortex combi boiler was stuck on and therefore not allowing the central heating to run, it cuts off the central heating pump if hot water is needed.
Easy enough to remove the switch and I gave it a clean and a wiggle on/off to check it works. It does.
So I reinserted It, tightened it up and it worked fine for a while but last night it happened again - flow light staying on when no taps opened so heating not coming on. I removed it once more to check and I have noticed that just inside where the flow switch paddle sits there is quite a lot of scale, this could potentially be catchingthe paddle - can I tip a bit of descale in that part of the pipe and see if that helps?
Thanks in advance for advice.

 

[Exedon]

Certainly try some descale and gently scrape off what you can.
Flow switches can go faulty we tend to change if any doubt.
Occasionally you have to trim/file paddle to make it to clear.
You really should address hard water issues if flow switch scaling up you plate to plate can't be far behind.

 

[c.zakalwe]

Here in Jersey the water is fairly hard, so I'm not surprised there's is some scale. The boiler gets regularly serviced though. I'll try the descale and give it a clean out and was planning buying a new flow switch just in case, they're only £45 on amazon.

 

[Exedon]

There are 2 flow switches make sure you have right one! down to age of boiler.
We look after quite a few oil combi's the ones with a proper ion exchange water softener on are noticeably less problematic.

 

[c.zakalwe]

2?
I didn't see the other, but the one on the top at the mains intake is the one causing the problem

 

[Exedon]

Sorry should have said 2 different flow switches available depends on age of boiler which one.

 

[c.zakalwe]

gotcha! I've double checked and hopefully ordering the right one.
Thanks