Vailant Combi Boiler - No Hot Water

[DavidGJ]

I have the same problem as another post here.... hot water only when heating is on. Could this have been caused by deposits in the water supply??? Since work on the water mains four months ago, we have had black particles in our water supply, but so far only evident in the cold water to the bath. The bath is the first point of supply in the house, with the boiler next.
I have complained to the water company who are sending an inspector out, but any advice on whether this could have caused the problem would be appreciated.
Thanks

 

[DP]

boiler model would help

 

[DavidGJ]

Sorry DP....
Its a Turbomax VUW 242/1/E
I have checked through the fault diagnosis sheets in the manual and the problem is definately in the cold water inlet area as the DHW microswitch is not operating when the hot water tap is turned on.... but the boiler kicks in fine if I flick the switch up with a screwdiver while the water is running....
The next step is to check the inlet filter, diaphragm etc.... but I am a bit unsure about doing this myself, and I am curious to know before hand if the problem was likely to have been caused by the black solid deposits in the water.... If so Welsh Water can repair it!!!

 

[DP]

White plastic arm can break or be out of adjustment leading to no HW demand recognition. This Vaillant is a pigs ear compared to earlier quality boilers from this maker.

HW during heating demand means hot water will not be at correct temperature as primary circulation will be to the rads as well as calorifier

 

[sifu]

In addition to DP's post, the valve has now been modified with a different microswitch and lever. I'm getting into double figures now with the number I've changed, and I still find them a right pain to change. It's an expensive part (about £120 I think) and fairly difficult to change without creating leaks elsewhere. I would suggest you get in touch with BG and go on to their maintenance contract for a year. They do a scheme where they cover *one* fault and insure your system for a year for about £260, this includes an annual service. See http://www.house.co.uk.

 

[DavidGJ]

Thanks guys, good news is Welsh Water have agreed to repair the boiler and are putting a filter on the stop cock to make sure it doesn't happen again - as I was the only one in the street without one already they couldn't argue much.
"Sifu" Good idea on the BG maintenance.... had planned to do it before just never got around to it.... will definately do it once things are all back in working order.

Merry Christmas All.... and may all your leaks be the result of too much beer