Boiler issue - no CH but get hot water?

Pandilex

Hello, recently had some people in to do plastering work and they removed and replaced a radaitor. I was told they repressurised the system afterwards.

When I turn the central heating on it doesn't work, but hot water works.

The boiler I have is a vokera 29 HE, it was last serviced in June.

When the boiler is set to hot water only, it makes no noise until a tap is turned on.

When I set it to CH and hot water, the boiler makes a chuntering noise like it's doing something constantly, but the noise of the boiler firing up only occurs when the hot tap is switched on.

The light flashes indicating temporary fault.

Before I get a service guy out could this be a simple problem of a valve not being turned on or something like that from the work they did?

Viberduo

I had the same issue a few years ago with a Vokera, Can not remember for the life of me remember how it was fixed but a year later I had the opposite issue no hot water but had heating and it turned out it was a part that cost like 99p and was tiny had gone.

Actually now I remember it, I think it was down to the pressure in the unit and I think just opening the valves helped or it may have been like the hot water and it needed a small part, or I may have needed to bleed the radiator too.

Again this is all guesses so dont do anything to others say something.

PheoUK

Air lock, have you bled the radiator?

patriick

I'm not an engineer but it sounds like the boiler diverter valve is not operating properly.

Most combi boilers have a main heat exchanger that heats up water for the central heating and a secondary heat exchanger which is connected in place of the CH (via a solenoid or motor) when you turn a hot water tap on.

The chattering could be the solenoid/diverter valve sticking and not switching properly. The fault light is presumably because there is a CH demand and the diverter valve is still in the HW position. The CH must be pressurised ok or you wouldn't get hot water either.

Maybe the decorators dislodged some dirt or something in the system which is blocking the valve.

Should be a simple problem for your service engineer to sort out. I would give him a ring and describe the symptoms.

rustyboy21

Had this this morning with my WB. Had hot water, but the wall stat was saying boiler on for CH, but rads cold.


Checked the pressure, was just down to the red. Filled it up again and everything is now fine.


As above said, check your pressure. Last time it happened, I had heating, but no hot water , this time the opposite.

Pandilex

Thanks for the advice guys. The pressure is reading as fine, so perhaps it's just time to give the plumber a call. I considered taking the front off the unit to see if I can see anything obvious but not sure if I will end up electrocuting myself...!

I just wanted to avoid someone coming out and going 'umm, you just need to press this button...'

patriick

Apart from turning the power off and on or pressing the reset button there's nothing you can do, please don't try taking the cover off!

You need to call your engineer.

patriick

There is a CH forum here:

http://www.diynot.com/forums/viewforum.php?f=7

There's a recent post about your boiler and it seems there is a Vokera expert on the forum. You could try posting there if you like.

There's another good CH forum here:

http://www.ukplumbersforums.co.uk/central-heating-forum/

Pandilex

Thanks I made a post there, fingers crossed!

kaya

The symptoms sound like the three way valve , I would bleed the rads first of all. Did you use the heating before the building work was done( I only ask as mine has been switched off for 6 months due to the hot weather). If you haven't used it recently then it's the diverter valve motor head that's gone(I have a vokeira boiler and mine needs replacing every 18months or so) . You can get the valve heads for about £25on ebay and they are only held in by a spring clip, you do not need to touch the gas supply to change it or be qualified in any way . You can call out the manufacture who do an all inclusive parts and labour price and should have all the bits with them, please don't call a plumber as they have usually had very minimal training on boilers , you need a heating or boiler engineer who should diagnose the fault correctly and quickly rather than a plumber who will scratch his head a lot and fit a good few parts at your expense before finding the fault . You wouldn't call a boiler engineer to fit a new toilet or sink would you?

southcoastrgi

patriick wrote: »

There is a CH forum here:

http://www.diynot.com/forums/viewforum.php?f=7

There's a recent post about your boiler and it seems there is a Vokera expert on the forum. You could try posting there if you like.

there is loads of experts on there me included & not one of them will give you advice if it involves gas or taking the boiler to bits as it's against the forum rules