CH is working ok but HW isn't on Vaillant TurboMAX plus 824E

[peca27]

I've got a 3 yr old combi Vaillant TurboMAX plus 824E and i've got a problem with the HW temp.

During the last few weeks i've noticed that when the CH is on, the HW isn't working properly. The HW comes thru at the right pressure, but the temp isn't warm enough - it's not freezing cold but it's prob at approx 20% temp of what it should be.

But then say for eg, if the CH is off, the HW is always ok. I've checked for leaks etc (of which there aren't any), there's no error codes at all & the pressure is at 1.3b & is ok.

Like I say everythin seems ok, until the CH is on & only then we seem to be getting the problem with the HW every now & again. But i want to resolve the problem before it gets serious, any advice would be welcome + would anyone recommend a service by a CORGI plumber for eg?

Thanks to all in advance.

 

[Bahco]

Could be the diverter valve is sticking.

Combis are hot water priority so the heating will go off when the hot water is run.

 

[peca27]

if it is the diverter valve, should it have knackered in just 3yrs? i thought these boilers are the dogs bo**ocks

i've been chekin on the web, a new diverter valve would be approx £75

is there any way i can clean out the existing diverter valve? if not is it a straight foward job to replace the diverter valve with a new one?.......again thanks for your reply

 

[Bahco]

Hopefully Kev or the other pros will be able to advise you further on your problem.

I have the same boiler and to date (2 yrs ) have had no problems

 

[peca27]

i've also noticed that when i get the problem of the HW not workin, if i press the boiler reset button it solves the problem......is it an electrical problem then?

any ideas would be appreciated is i've got a feelin it's all gona hit the fan pretty soon

 

[peca27]

come on guys, i'm gettin desperate.......the problem is gettin worse - any advice at all would be welcome

do i just go + get a new diverter valve or try something else?

 

[ChrisR]

An ew diverter is easy peasy to fit but I don't think it's the problem in your case. It would always work or not work - it doesn't know whether the heating's on. The early 824/8 diverters are all failing though. A boiler engineers will tell by looking at it if you have an early one or not.

The only thing which is aware of all inputs is the pcb, expensive of course if you don't know where to go.

I'd call Vaillant tech, but they sometimes only advise Corgis.

 

[noodlz]

Have you got the "Instructions for installation and servicing" - if you haven't can be downloaded from www.vaillant.co.uk

There gives faultfinding charts and instructions for diagnostics. Might be of help.

 

[peca27]

thanks for the replies - what is a 'pcb' ChrisR? is it the circuit board? cos i'm beginning to think it may be some elec fault. I've tried Vailant but no-one is picking up

Noodlz i've got all the manuals - not any help at all.....as i say i'm not gettin any fault codes either.....the manulas rely on a fault code showing & then a remedy for the problem thereafter.

thanks again guys

 

[kevplumb]

look in the servicing section

diagnostic mode

d 35 is the diverter valve position

one other check run the water and feel if the heating flow warms up

 

[noodlz]

As Kev says, check servicing section. Gives info what to check when no fault codes & also run diagnostic checks on parts.

Can't do that with any old boiler...it's a good 'un

pcb is printed circuit board