Vokera Linea 24 no CH but have HW

[markdoncaster]

Anyone help?.
I have recently moved, i have inherited a linea 24, during the summer everything was fine, now i have switched over to CH & HW the damn thing doesn\\\'t want to play. I can get HW all the time, just no CH. If i reset the boiler, during the combustion check i have hot radiators and hot water, once the CO has finished i go back to having only HW. the timer does not seem to be the problem, as i have switched it to the constant position and i have the same problem.
The knobs are okay and not broken, i have checked them.
The water pressure is at 1 bar.
There are no error messages are on the display.

I have tried the advice given in previous peoples posts, but no joy.

Please Help

 

[Paul Barker]

It is not obvious when the selector knob is broken because mecahnical contact is indirectly transferred. You have to remove the bigger pcb and then the smaller pcb behind it to get this spindle out and actually see if it is broken.

Otherwise, the first thing to try is to put a jumper in place of any system controls and see if it comes on for heating.

 

[Alexcsp]

The Most likely thing wrong, is that the selector knob is broken where it goes through to the Small PCP internall,y this is a very common fault in this boiler.

The thing still clicks as if it's ok, as the clicking mechanism is provided by the housing.

To check, unfortunately you have to remove the main PCB and then the smaller PCB.

Vokera have made a modifiction to the switches , so the new ones are a two piece effort.
They are usually a stock item in the spare parts places and only cost about £2.00 each, but they can be tricky to fit if you don't know what your doing.

 

[Paul Barker]

de ja vu

Having a few of these on the van is good for the beer fund. There are plenty of Vokeras in town with still not broken shafted yet but they all get shafted sooner or later.

Just aswell manufacturers leave these little flaws or our job really wouldn't be worth doing.

 

[markdoncaster]

I have taken both the large and small pcb's off and checked, the knobs still had the shafts intact, to double check i took the knobs off too..in the process breaking 2 of the shafts..lol..
I have reset the system again, using a piece of plastic to turn the centre selector. The system reset fine, but still no CH.

 

[Jezzy]

Sounds to me like the diverter valve isn't switching back correctly/hole in the diaphragm, diaphragm kit needed, but i'm only learning myself so get a 2nd opinion.

 

[Paul Barker]

So have you bridged out = and TA to eliminate external influences?

 

[markdoncaster]

Erm, i dont know what that means. I have put in a new timer, since having the problems, however i kinda got stumped. There were 5 connector points on the old timer (with 4 wires attached 1 spare) and on the new timer only 4 connectors 1 of which is spare, so i have only connected 3 wires...mains live, mains neutral & 1 ta, the other one was also ta but thats now spare.....

 

[Paul Barker]

That's your problem. There have to be two control wires on the clock one common and one NO.

White and white and red go back to TA and L on the board.

The edge connector on the board is the longer one on the left. There are 7 connections, reading from the front N, N, L, L, TA, TA, =.

terminal 4 (L)and 5 (TA) are the ones that go to the clock. Basically your clock sounds like it has four spades, two of them should have a symbol beside them that indicates that it is the motor of the clock the other two should have a make break symbol, like a switch, these are the two you put the white and white and red to. If the clock already goes round and kleeps time you are half way there. It doesn't actually matter which way round the other two go, but both must be on.

What is going on is the boiler sends a live out from the L terminal to the clock it comes back to TA, then goes out from TA to the roomstat and comes back to =.

 

[markdoncaster]

i have bought & fitted a vokera timer now, the wires are back to how they were. the clock is going round, keeping the time, but still no CH.....

 

[Paul Barker]

Oh dear. This must be very frustrating for you.

You still have to backtrack and eliminate external influences by making a temporary link between Live and = terminal.

That is on the left hand edge connector nearest the front, the longer one, put a link between the furthest pin whis is =, and the 3rd or 4th from front, both of which are L.ive.

 

[markdoncaster]

i have put a temporary bridge connection in between live and =
Still no CH....i'm banging my head against a wall here...lol...

it sits there all happy, when the hot water is turned on the boiler fires up, no problem. but the radiators still remain cold, unless i do a combustion test by pressing the black toggle on the small pcb.

 

[Agile]

The diverter is operated by a motor actuator with three connections.

Remove the spring clip and take off the motor.

Push down on the pin in the recess vacated by the motor and the heating will come on.

EITHER the motor actuator ( or its cable ) is faulty !

OR the PCB is not powering the motor actuator.

If you turn the motor upside down and watch the brass pin it will be up for heating and down for DHW. If its not moving then if you are competent then measure the mains voltage between the centre connection and each side. I think its left live for DHW and right live for CH as viewed when operating in the boiler.

Costs about £40 if its the motor, much more if its the PCB.

If neither, then I will advise further just as long as you have carried out my advice to the letter.

Tony

 

[markdoncaster]

I have removed the actuator
It pushes upwards when the combustion test is running, allowing the central heating to heat the radiators. i can't measure the mains voltage between the centre connectors, i dont have the correct tool.

When i press the pin in the diverter, the heating does come on.
so do i need a new motor actuator?

 

[weargas]

mark, forget the combustion analysis mode button it's telling you nowt and leading you down the path. It's an engineer function and thats all. As tony's said, put the boiler into ch mode and test for 240vAC on the actuator. If you have 240v your actuators gone if you haven't it's your PCB. If you haven't got the gear to test it call someone who has.
Or, when the boiler is completely cold turn on the ch. If the pump runs and the boiler fires up but no heat goes to the radiators it's more than likely the actuator. If nothing happens at all (no pump run, no firing up) it's more than likely the PCB. This is a rough test only, the only accurate way is to use a multimeter and test for voltage.