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Ed Sirett Ed Sirett is offline
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Default Vaillant Combi boiler hot water problems

On Mon, 16 Feb 2009 18:14:50 +0000, Broadback wrote:

A.Lee wrote:
Broadback wrote:

My Vaillant Turbomax Plus boiler is having problems supplying hot
water.
The central heating is fine but the hot water,though it
works,intermittently goes cold. I first noticed it when using the
shower, I thought at first that the shower was at fault, however on
checking it also happens when running the hot taps. I have checked
that no one else is calling for hot water at the same time and have
tried adjusting the water temperature to no avail. At a guess it runs
hot ok for about 20 seconds then goes cold for 10 seconds. Any ideas
please?


Does it continually go hot then cold then hot etc? If so, possible hot
water heat exchanger blockage - quite common apparently..
Or, Primary heat exchanger fault, or possible pump failing - both less
likely, but possible..

Or does it run hot for 20 seconds, the stays luke warm? That would
point toward a divertor valve fault.

Alan.

It alternates hot and cold.


One or both sides of the 2ndary heatX.
Either
Replace with a new unit and then descale "the spare" at your leisure.
Or.
If you can do without heating and HW for a day then descale the existing
unit. You will not get good results trying to descale either side in
situ. You may, if very unlucky spring a leak between the primary and
domestic sides when you descale.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
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