Problem Vaillant boiler - Please help!!

[nozzzaa]

Hi,

I have a Vaillant Turbomax plus 824E

i have a bit of an issue wondered if any experts could guide me as to what it is. i have had a plumber friends glance over it but as he does not normally service and fix boilers so doesn't know whats wrong.

the hot water kicks in fine, and flows to correct temperature when i move the setting for it, however the heating does not, i've tried flicking all the switches but nothing, the only way i can get it fire up is when i hit +,- buttons together which as i've researched kicks it into SFHmode (service for heating), however this mode takes it straight to its highest set temp, so what it does is fire up and the rads do get hot but only until it hits 85 degrees then it shuts off again!

does anyone know what could be the problem.

thanks

 

[ALCPlumbing]

Try switching your heating on at both the timer and room thermostat and then press the 'i' button on the boiler display. This will come up with a status code. Let us know what it says. If it remains on S30 then the boiler is waiting for a demand and the problem lies with the external controls.

 

[nozzzaa]

i havent got a room stat mate just controls on the boiler itself

 

[ALCPlumbing]

What I said still applies. Have you turned the heating on at the timer and checked the status? Is it the built in mechanical timer you have? If so they usually have a green light that indicates the heating is on. Does the boiler do anything when you turn the heating on?

 

[nozzzaa]

sorry bud, yes its the mechanical timer and yes it has a green light etc

when i set it to the timer to on , the green light comes on but no fault code when i press (i) just gives temp and 5.30

 

[nozzzaa]

when i hit the + and - button together everything fires up and it displays SFH (water pump starts running etc) however hit max temp then shuts off in this mode

 

[ALCPlumbing]

In that case I suspect you have a faulty timeclock. If you definitely don't have a room thermostat you can easily test to see if the timeclock is working.

Turn power off at the boilers plug or fused spur. Then you need to disconnect the timer. It will just pop off and pull out. Now turn the boiler back on and the heating should run constantly now. To control the heating you can use the boilers heating thermostat on the front. Turn the dialj right down and the heating should go off and vica versa.

 

[nozzzaa]

ok so heres the boiler issue done a little video
first one is of it kicking into sfh mode second is after it hits max temp and shuts off

https://www.youtube.com/watch?v=zbDO1Xz5-Yk

https://www.youtube.com/watch?v=G9-KEtNuJcE

 

[nozzzaa]

In that case I suspect you have a faulty timeclock. If you definitely don't have a room thermostat you can easily test to see if the timeclock is working.

Turn power off at the boilers plug or fused spur. Then you need to disconnect the timer. It will just pop off and pull out. Now turn the boiler back on and the heating should run constantly now. To control the heating you can use the boilers heating thermostat on the front. Turn the dialj right down and the heating should go off and vica versa.

im struggling a little as to how to get the timer off can you advise a little morethanks mate

 

[ALCPlumbing]

The timeclock will just pop off and pull away from the front of the boiler. You need to leave the radiator temperature turned up as well. Just put a flat head screwdriver under the edge if it while it's turned off and pop it off.

 

[nozzzaa]

thanks for that you were exactly right!! got a screwdriver in there and it just popped off with four long pins connecting it -

anyway done what you said and turned it back on and still nothing, tried pressing + - again and it fired up into sfh mode again

really appreciate your advice btw.... what next???

 

[ALCPlumbing]

You've definitely not got a room thermostat have you? Is the heating dial on the front of the boiler turned up to full? If you turn the boiler on with the timeclock disconnected does is still say S30 when you press i? Also when you rotate the heating temperature dial on the boiler does the digital temperature display on the front change accordingly? It's possible the dial is broken and not actually adjusting the temperature. It should tell you what temperature you are setting it to, as you rotate the dial. Obviously if it doesn't change as you rotate it then there is where your problem lies.

 

[Agile]

His video shows that the knob is turning the pot on the PCB.

It seems to me that the only way forward is for testing with a meter!

Tony

 

[ALCPlumbing]

Unfortunately Tony's right. The only tests that need to be done now require the use of a multi-meter to properly test where the fault lies.

 

[ALCPlumbing]

If you pull the front of the boiler down as you did in the video so you can see the electrical connections. Here you can see where your power cable comes in and connects to the boiler. Right next to where the power cable connects you'll see terminals 3 and 4. Is there a connection between 3 and 4. This is the live out to a room thermostat and the switched live back which is used to fire the boiler. When you are not using a room thermostat there must be a link between terminals 3 and 4 in place of a room stat. I couldn't see one on your video but then it wasn't very clear. Obviously turn the boiler off first. It's unlikely this is the problem as your heating would never have worked without this link but it's the only thing left before calling someone in.