Vaillant turbomax vuw 242/1 e - keeps needing reset

[scottyab]

Central heating boiler (vaillant turbomax vuw 242/1 e), which has started to fail for hot water or central heating. The flashing light comes on after 30 secs or so and then we reset and try again and repeat until it kicks in and starts heating the water. Sometimes it'll work after 1 reset, sometimes it'll take 20.

Here's a exciting video of the issue: http://youtu.be/ZseZhGZ8-bg

Pressure is 1.5-2.

The plumber who checked it out said it could be either a switch or a board. The switch was ~£30 so we went for that first but this has had no effect.

I hoped a wider audience might be able to suggest faults before shelling out on a £400 part.

Thanks.

 

[Agile]

There can be many causes apart from the PCB which is less than £200 anyway.

I dont agree with your plumber's attitude!

If engaged to diagnose the fault then he should not be charging you to try parts.

We call those nupties parts changers!

You need a boiler engineer not a plumber.

Tony

 

[The831Bunny]

The pressure differential switch (possibly 'the switch) the plumber changed is connected to two small tubes that convey the water from the pump. These will probably be blocked. Get him back to remove the PDS and check/clean.

Failing that, the pump is sticking/jammed. The boiler is telling you it can't confirm any primary water flow.

 

[Agile]

That can be visually watched to see if its operating!

No need to change it just to see!

 

[The831Bunny]

Can't see where I said change it Tony!

The debris in the tube(s) can cause intermittent PDS operation, so always best to dismantle and clean to illiminate!

 

[bell824]

again 831 is spot on the money p/d switch is the biggest reason for this annoying fault (normally first thing in the morning after the sytem has been of for a few hours).
and as 831 has said more than likely no parts required and 1hr of an engineers life to repair.

 

[Agile]

The OP's engineer suggested the switch.

I pointed out that it can be visually checked.

The OP's engineer changed it and it did not solve the problem.

But there is no suggestion that he tested or cleaned the bundy tubes.

Tony

 

[scottyab]

Thanks for the feedback, I spoke with the boiler engineer and although he didn't clear out the tubes but swears it didn't need it and there is no residue on the switch and thats where it would collect.

He also mentioned that the fan is coming on before the pump. Dunno if this changes people's guesses to the problem.

Current choices replace pcb, or call vallient to do a fixed price fix, or call anther engineer. I'm leaning towards calling vallient.

 

[gazdaz36]

In my experience if there is a blockage it's usually on the chrome fixed pipe rather than the copper capillary tube between the PD switch and diverter.

Don't start going down the PCB route I'd be 99.9% certain it won't cure the problem.