Three leaky flow switches ?? :-(

[Heatslave]

Hi,

Hope someone can help with my aging Worcester Heatslave 15/19 RSO oil combi ??

I noticed a leaky cold water inlet flow switch the other week, so replaced it with a genuine Worcester part............which leaked where the red threaded plastic bit connected to the brass bit (technical talk here, I know !!). I contacted the supplier who said it was just a rubber washer, so take it apart, put it back together and try again. I did this and it still leaked.

I got another replacement and the exact same thing has happened again ?? I don't think two new flow switches could be defective. I've turned the water pressure down, thinking it could be that blowing past the rubber seal but it is still leaking ??

The only thing I can think is that the system could be over-pressurising for some reason ?? Noticed lately there's a canny clunk when the DV valve kicks in for the hot water heating when the central heating is on ??

Any ideas please ??

 

[picasso]

Are you on a water meter ?

 

[Heatslave]

No. How might that affect it ??

 

[DH6]

Non return valve in meter could cause a spike in pressure

 

[oilhead]

Are you replacing the complete valve or just the switch part? If the switch part, then you may have difficulty if past leakage has damaged the mating surface.

 

[Heatslave]

Thanks for the info on the meter, didn't know that.

Yes, replaced the completed valve - twice.

I can't see it being two defective valves ??

 

[oilhead]

Have had similar problems with these, not just on Worcester. It is possible to overtighten the switch on the base and cause leaks, but if the leak is persistent, then the insertion of a fibre washer can cure it. You just have to make sure the paddle still operates. If it sticks open, then the boiler will go to limit.
Where a similar unit was used with Warmflows, they stipulated that the cold water inlet should not exceed 3 bar.

 

[Heatslave]

Great stuff Oilhead. Thanks to all for taking the time to reply

 

[Agile]

An obvious early question was what is your static mains water pressure?

Even if 3 bar during the day it can often get to double that at night when little water is being used!

Tony

 

[Heatslave]

I live out in the sticks about 200 metres from the village. I'm in a cul-de-sac of 14 houses, and there's a booster pump at the bottom of the street.

Wonder if it's been going ape ??