Vaillant Turbomax DV?

7 Aug 2008
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United Kingdom
Hi again,

My Grans boiler is giving her trouble again, it is a 9 year old Vaillant Turbomax plus 828e. Occasionally the radiators heat up when not asked to and the hot water is just about warm, today the heating was on and when I opened a hot water tap no hot water came out at all and instead the radiators got very warm. It took several attempts + a lot of swearing for the hot water to come through :(

The heating is working perfectly.

Is this a DV issue and how hard is it to resolve?
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Sound like a possible diverter valve problem.
Luckily the turbomax is one of the easiest dv to change.
Search for the instructions and follow them.
take the head off the valve, it just unscrews, no water. then use a pair of snipe nose pliers try the pin in and out, you'll prob find it quite stiff.
Definately sounds like the famous dv problem. very easy to change, a schoolboy could do it ;)
Thanks guys.

Mick, if I do what you say and then replace the head should it work okay?
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Thanks guys.

Mick, if I do what you say and then replace the head should it work okay?

no it wont fix it, but it will give u an idea if its guffed. The pin should move freely, but the usual fault with these is the ball swells inside making it stiff to move. When u put it back on pull the pin all the way out first as it will make it easier to hook the ball into the socket to put it back. You'll see what i mean when you get it off.
Don't pull the ball out, or you'll get moist and excited.
Hehe okay thanks, and if does indeed need replacing what should be replaced? The whole valve inc actuator or just the valve?
You can buy the head without the valve, but not t'other way round.
(maybe just maybe the rod coupling's different, or maybe it's a bit of a scam... ;) )
Thanks. To change the valve can is it a simple case of draining down the boiler, removing the old valve and putting the new one in place? All I've done on this boiler in the past is flush the system, remove the plate HE to clean and re- pressurise the EV.

I am not sure if I should use the boiler isolating valves in case they leak afterwards so should I just drain the system and boiler and leave the valves open?
dont really need to use the isos normally but these particular ones are generally solid if it makes you feel more comfortable working on it.
its easier to replace the dv than removing the plate so you should have absolutely no bother if youve already done that job. 3 connections nothing in the way.
Okay, shall I replace the o-ring the DV connects to on the plate HE? I have some Vaillant ones spare from when I cleaned the plate HE. Also ISTR all sorts of wires coming out from the DV head, will these need removing and reconnecting?
All washers you will need come with the valve and motor.
The wires are connected to the motor head with a plug. Just pull it out.

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