Vallant Eco Tech plus 637 r1 just turns off....??

Hi,

I think I am heading for an early grave!!!

I am having a nightmare sorting out this system! Any advice would be greatly appreciated.....

My model of boiler is a Vaillant Eco Tech plus 637 r1

History....
The boiler has been recently serviced (two months ago) and had a new F75 error pressure sensor V3 fitted after problems with that. All was good for a few weeks. Then the hotwater would work, the heating would not. A new Wireless thermostat receiver was fitted, and the heating started to work - problem solved, but NOW....

Regardless of if I want hot water, or heating, both, or just one or the other (using the Honeywell timer switch) the boiler fires, runs for about 3-4 minutes, then turns off. The flame goes out on the screen, all that is left is the icon of the pump (round circle with triangle in it) and the radiator icon, and the temperature - on the LCD screen.

Then the pump icon goes out, then the Rad icon goes out and I am left looking at the temperature reading (30ish) and nothing on the digital screen at all.

When I try again, everything off and on, from master spur swithc, the pump light comes on, then the rad icon appears, then I hear a cluncky click sound and the pump icons disappears, and then appears 10 seconds later, I hear the same clunk and out it goes again. After a few more clunks, the icons all go out, and all that is left is the Temperature.

I cannot believe what aggro I have had with this system.

The pressure is good at 1.0bar for cold, and the twisty temperature controls on the front are in the right positions.

Also to add, I did replace the Honeywell timer recently, vainly trying to fix the F75 - which has been sorted. So I think I can rule out the timer as well.

There are no error displayed for my latest issue.

If ever there was a product, I wish I had avoided 7 years ago - this is the one!!!!

Any advice would be great.

Regards,

Richard.

Are you sure it's been fine since they replaced the thermostat till now? It sounds like it's permanently switched live and just heating up the bypass circuit.

Well all I can say was, the hot water turned on when I asked it, and the heating worked totally 100% reliably for a while with the new thermostat.

Not sure what you mean by permanently switched live?

Thanks,

Richard.

One update to maybe help a bit...

I try the Sfh thing with + and - together for a few seconds, and the boiler fires, heats the rads, and the pump icon is on. I don't want to leave that on for more than a few minutes, but it does show the boiler seems functional.

When it is in a state of refusing to start and I press the i button, I get S30 - which I believe means it is not being asked for heat, so it is as if the new control panel and new thermostat are not asking for heat???

One suggestion was give was it maybe a new PCB or a dead pump, but does that sound likely to you?

Thanks again.

Based on what you have said it seems to me there could be several problems and it will need an engineer at the boiler to test it to identify the problem.

Tony

The shaft on the twisty temperature controls as you describe them have a habit of breaking on these boilers meaning the temperature you are asking for isn't being transferred to the boiler, so you may be asking for 80 degrees,but the boiler may only be set at 30.
Watch the temperature on the display as you turn the bottom knob up and down,the display should alter with it.

No the knobs do adjust the temperature - I can see their movement relate to the temperature adjustment on the screen.

The maddening thing is that it all seems to be working fine today!!!

And I have booked someone for Tuesday

What to do?