Vaillant TurboMax 242E No hotwater

7 Nov 2005
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United Kingdom
The hotwater on our turbomax 242E has stopped working. The boiler doesn't fire up when the tap is turned on. We've had a similar problem before however the symptons are different this time. Unlike before, we don't get any warm/hot water when the central heating is on. Can anyone help and would I be able to do the job myself?
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It sounds like a diverter valve failure.

Its a tricky job for a professional but some amateurs have managed it.

Tony Glazier
Managed to speak to a Plumber this morning who also suggested a Diverter valve failure, so sounds likely. Thanks for the response.
It's probably just the motor and quite easy to fix. (no plumbing)
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I've had the same problem on 3 occasions on my 5 year old combi and it's always the diverter valve needs replacing and their not cheap at well over £100. I took out insurance that cost less than £100 for the year and it worked out allot cheaper than having to pay a plumber and you miss out the hassle of DIY. If your system is old or a mixture of old and new like mine is, then it will probably fail again.
joe-90 said:
It's probably just the motor and quite easy to fix. (no plumbing)
Nah - it'll be the input/output flow switch disc solenoid thingy. Always is.
The itinerant dimwit returns:
joe-90 wrote:
It's probably just the motor and quite easy to fix. (no plumbing)

We'll take that as a poor attempt at a wind-up and not worthy of comment, beyond saying that there IS no motor.

Vaillant diverters were tested on the public on two models of boiler. Once they'd got the design right, the problems were cured. At least it seems that way to me, because I've hardly had to fix any of the later model diverter valves.
Had a look in the boiler and it looks like a part is corroded and leaking. I don't know if this is causing the problem, but it doesn't look good. Not knowing the name of these parts I'll describe what it looks like.... It's sits on the top right hand side underneath the burner. It has a red switch and two cables plugging into it. There's a small lever coming out of the top and this and the lever sits about 5mm below the gas burner. Vaillant have sent me a manual so I'll take a look at tonight and see if I can identify it.
Possibly differential pressure switch. Have you tried Vaillant site for downloads of parts lists, servicing instructions, etc.?
SOunds like it - the low pressure switch. If that failed of course, the whole boiler would be affected.

Your diverter valve is over to the right. A Vertical brass thing, wide at the bottom, about 200 mm tall. There's a small switch on it, part way up on the right, which will be either black or green. Olduns were green and suffered from getting wet. ANd the green era DV's had a fault which was fixed later, so what colour is your microswitch? If green, expect to change the whole DV.

The whole DV can be stripped and serviced , but a new one is £131plus vat, rrp. Could need just a diaphragm.
This is it, viewed from a strange angle

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