Vaillant Turbomax problem

[Stu31]

I wonder if anyone could help, we have a Vaillant Turbomax combi (28kW?). The heating is working satisfactorily, the issue is with the hot water. When someone has taken a long hot shower the boiler seems to work fine, the problem arises when the next person wants to use the shower, the boiler just doesn't come on or fire up, there is cold water only coming out of the shower.

Could anyone cast any light on what the problem may be.

Interestingly this doesn't seem to be a problem if someone has a short shower with the shower temp set lower.

Many thanks

 

[Agile]

Its very difficult to come to any conclusion without being at the boiler to do some tests.

It would be classed as an intermittent fault and they can be very difficult to find as they do not present when an engineer visits.

There is a safety switch associated with the fan which might be intermittent as thats a common fault on your model. Sometimes the contact resistance will give a clue as to its condition. But anything to do with this should be investigated by a comnpetent boiler engineer for safety reasons.

Tony

 

[ianniann]

As described, it is almost certainly some sort of cutout. The symptoms suggest some sort of heat soak or buildup once the demand is removed, but there are so many pump and fan overruns on a modern boiler that there's lots of possibilities.

 

[Stu31]

Thankyou for your replies

 

[simond]

I don't repair many turboMAX; however, the first thing I would check would be the hot water demand detection.

Vaillants use a series of S (status) codes to indicate where the boiler is at in its' sequence.

If you press the i button and then open the HW tap somewhere, you should see S.10 come up in the display for a short period. The green LED should also be flashing.

If you do not get an S10 the boiler is not aware that you have opened a hot tap, and you will get cold water.

There is a flow switch inside the boiler that determines when you demand hot water, these can get stuck or work intermittently.

If there is a fan or ignition problem, you would expect the boiler to lock out and require a reset.

PS: Press the i button to cancel diagnostics.

 

[Agile]

If his boiler has the digital display then I would have expected he would have mentioned an "F" fault code showing ???

Tony

 

[Bunnyman]

More info please dore it have plastic drop down door with digital displY or metal side opening door with row of lights up left hand side

Untitled

• Bunnyman
• 26 Mar 2010
• 499