vaillant combi no hot tap water?

i have an vaillant turbomax pro 24e I had luke warm water then it whent cold But if i turn on the hot tap the boiler fire up but the flame goes out but still have heating

mikechid
November 2013

The hot water on my boiler goes cold if I am running the water continuously for around 5 minutes with the heating on. I was checking what was wrong with the boiler and ran the hot water tap whilst the heating was on. I found that after a few minutes the water pressure appeared to go down. The water went cold at this point. After a short period it would increase and the temperature would go up again. I was checking this for about 15 - 20 Minutes. During this time the radiators went cold. What could be the cause of this problem?

Paul
November 2007

Sorry but this boiler doesn't have a microswith or a diaphragm on the D/valve. They were on the old 242/282 e turbomax boilers. Hope this helps.

John
November 2006

First check that the microswitch on the side of the diverter valve is being operated when the hot water tap is turn on. If it is, the switch is probably faulty (about £8). If not, check the diaphragm in the diverter valve (£3).

Mike V
November 2006

There is a common divertor valve problem with this boiler. Sometimes the D/ valve sticks in the mid position when you turn on hot water. You can check by making sure the heating is off and turning on a hot water tap, feel the heating flow pipe (big one, 22mm furthest on left) to see if it gets hot. If it does, change the D/valve.

John
November 2006

must boilers if they go below about 0.7 bar they cutout and go in what is called lock out mode. try to keep between 1-1.5bar.

hi-spec plumbing
November 2006