Help for a newbie.

[davyboy]

Hello all, I'm a newbie to the site and at this point I'd like to state that although I am pretty good at taking things apart / putting back together I am by no means a plumber.

I'm hoping that you guys might be able to help me to diagnose a problem with my boiler.
The boiler in question is a (12 ish yrs old) Vaillant 242 Turbomax, I'll try and keep this short, so here goes,
last week I lost hot water, (Heating still working fine) going from past experience I suspected the diaphragm.
I removed the old diaphragm only to find that it seemed in decent condition,(No holes) since I had bought a new one I replaced it anyway.
This is the first time I have done anything to the boiler myself, and I'm happy that I followed the correct procedeure when replacing the diaphragm.

When I tested for hot water by opening one of the wash basin taps half way (As I do usually) the boiler did not fire / supply hot water,
(I was not really surprised at this given the decent condition of the old diaphragm)
however, when I closed this tap and opened a bath tap fully, the boiler fired up no problem, after trying all the hot taps in the house, I discovered that with a tap at half open the boiler would not fire up, but at full open would fire up no problem.

I may have been able to get hot water last week before replacing the diaphragm by opening the taps fully, but as I only usually open them half way I'll never know one way or the other.

So guys, its over to you the experts, obviously there is some relation to the flow of water / the boiler firing, but what is it ?
is it some sort of sign that there is a problem somewhere else in the boiler, maybe a component beginning to fail ?
your help and advice would be very much appreciated,
Regards,
Davyboy.

 

[Gasguru]

You'll need to do a search on the forum....solving problems on these boilers can run to several pages.


The boiler should fire up at a minimum flowrate of 3.5 litres/min at 0.3 Bar.

Did you check the water ways inside the water section are not partially blocked with scale?

Did the pin slide through the stuffing box ok (normally best to replace the stuffing box).

Has the hot water microswitch and push rod been adjusted correctly?

 

[davyboy]

You'll need to do a search on the forum....solving problems on these boilers can run to several pages.


The boiler should fire up at a minimum flowrate of 3.5 litres/min at 0.3 Bar.

Did you check the water ways inside the water section are not partially blocked with scale?

Did the pin slide through the stuffing box ok (normally best to replace the stuffing box).

Has the hot water microswitch and push rod been adjusted correctly?

Hi Gasguru and thanks for the reply, we dont normally suffer from scale etc in the pipework as I'm up north in Lancashire, (Good water)
What / where is the pin you refer to and whats the stuffing box ?
also how do you adjust the microswitch and push rod ?
your help is much appreciated,
Regards,
Davyboy.

 

[davyboy]

Anybody. ?

 

[namsag]

edit ignore i missed turbomax bit.
As dangermouse says below, had this a few times and whole divertor needs changing

 

[Deleted member 105431]

you need a new diverter valve part no 011289.

 

[Gasguru]

Did it say Turbomax yesterday?

Being 12 years old it would be a combicompact.

If it is a Turbomax (black controls panel and green knobs) then make sure the venturi in the lower water is clean (and the small holes).Soft water can also create soft calcium deposits.

Try adjusting the microswitch (loosen the screw and swing the switch)....normally need it fully clockwise.

Otherwise the bow (the small plastic operating lever) may have partailly failed in which case complete diverter replacement is best option.

 

[mickyg]

Cut a small piece of card from a cereal box, place this under the metal lever that pushes down on the microswitch, this should keep it going a bit longer.

 

[Deleted member 105431]

Cut a small piece of card from a cereal box, place this under the metal lever that pushes down on the microswitch, this should keep it going a bit longer.

is that known as a pernament repair at bg?

 

[mickyg]

I wouldn't know, you'll have to ask someone who works there

 

[davyboy]

Thanks very much for the replies lads, it is definately a turbomax, (Black panel / Green switches) just to be certain of what you guys are saying, could you please confirm that as I understand it, the problem with the boiler not firing when a tap is only opened half way, is not the diaphragm / microswitch, but is the diverter valve.
Could it be the microswitch only and not the diverter valve, and if it is the diverter valve, will it eventually fail completely / leave me without hot water ?.
Also can these valves be refurbished ?
I only ask as I am pretty sure I have one that a vaillant engineer left behind when he came to change the said diverter valve some time ago,
your help and advice is much appreciated,
Regards,
Davyboy.

 

[Deleted member 105431]

Thanks very much for the replies lads, it is definately a turbomax, (Black panel / Green switches) just to be certain of what you guys are saying, could you please confirm that as I understand it, the problem with the boiler not firing when a tap is only opened half way, is not the diaphragm / microswitch, but is the diverter valve.
Could it be the microswitch only and not the diverter valve, and if it is the diverter valve, will it eventually fail completely / leave me without hot water ?.
Also can these valves be refurbished ?
I only ask as I am pretty sure I have one that a vaillant engineer left behind when he came to change the said diverter valve some time ago,
your help and advice is much appreciated,
Regards,
Davyboy.

you need to change the complete valve part no 011289. If you don't fancy it Vaillant will do it for £215 fixed price. if u do it yourself be carefull that you put the small pump screw in the top pump connection, don't break the plastic clip on cold mains and use silicon grease and new O rings. should take a pro about 20 mins.

 

[davyboy]

Thanks for the reply Dangermouse 46,
I've managed to find the old diverter valve that I mentioned earlier on, I believe there is a refurb kit that can be bought for this valve, what sort of cost would this kit be (Part number ?) and would it be worth it to refurb the old valve as opposed to buying a new one ?

At the moment the boiler is still supplying me with hot water as long as I open any hot tap fully, I was of the mind that I could refurb the old one whilst the boiler is still suppying hot water and then swap the one on the boiler at the moment for the refurbed one.

How difficult is it to refurb one of these valves, also are there any associated bits ("O" rings / washers, etc) might I need to complete the job correctly ?,
your help and advice, as always, is much appreciated,

Regards,
Davyboy.

 

[Deleted member 105431]

i wouldn't recommend a refurb myself-better off just doing a proper job! change the whole valve and the new one will last 5yrs plus. how long will a refurb?

 

[davyboy]

.

i wouldn't recommend a refurb myself-better off just doing a proper job! change the whole valve and the new one will last 5yrs plus. how long will a refurb?

Well, as a newbie to working on boilers, although over the years I've had basically ever other sort of domestic appliance (And engines etc) in pieces / back together, I dont know how long a refurbed valve would be likely to last,
but I would have thought that a valve that had been refurbed correctly using the original manufacturers kit should last as long as a new one, is this not the case ?

I only ask as it would seem from what I can find out so far, when refurbing one of these valves, all of the original internals are replaced with new parts from the refurb kit (Am i correct ?) that would only leave the original Brass casting to fail (Metal fatigue ?) which I would have thought unlikely,

Regards,
Davyboy.