Voker Linea 28 no C/H

[Gary67]

Vokera Linea 28. approx 9 y/o installation in a new build.

My problem is that I have hot water but no heating.

I have been installing two bathrooms in a flat. In one bathroom the existing rad was replaced with a 'designer' rad, and in the other the existing rad was removed, and the pipes capped. The system was sitting drained down for about 3 weeks.

New bathrooms installed, floors tiled. Job done - or so I thought. Having refilled the heating system a few days before, I was happy that pressure was sitting at 1.5bar. Stuck the heating on to test, but no heat to any of the rads. So I drained & refilled the system. Still no joy.

Pump motor is spinning & bled, and I can hear the divertor valve motor is operating.

Occasionally, after a reset, the boiler fires up the c/h but cuts out after the stat reaches 65c. The flow & return pipes leading directly to & from the heatexchanger get hot, but there is no heat at the RETURN isolating valve, and some heat at the FLOW isolating valve and a few inches down the pipe for a few seconds, but as soon as the burner cuts out it goes cold immediatley.

Any ideas? I'd be pulling my hair out if I had any.

Need to get the C/H working, and get off the job. Thanks in advance for your help lads.

 

[Gary67]

Really struggling. Any ideas lads?

 

[DP]

are the 22mm pipes under the boiler getting hot? what is the display indicating. make sure two valves on 2 pipes on the left are open, beyond that afraid heating engineer will be needed.

 

[Gary67]

Thanks for getting back.

The 22mm return is not getting hot, but the flow is briefly for about 3" below the isolation valve, but when the burner cuts out it immediately goes cold again. Would this be a symptom of a stuck diverter valve?

Display is showing the temperature. Green light is on.

Thanks for helping.

 

[45yearsagasman]

I'd be removing the pump head and check that the impellor is actually moving.

 

[Gary67]

Thanks for your reply 45yeargasman,

Will do. The notched head of the impellor is turning when I take the bleed screw out, but i will remove & check.

A new build. There's no chance this is a one pipe system? Highly unlikley I'd think.

Thank again mate.

 

[martyndc88]

sounds like no circulation id look at pump 1st, could be an airlock but highly doubtful, check that both boiler valves are open, all rad valves are open ect. could poss be a scaled up hex

 

[Gary67]

Thanks Martin,

System is in Glasgow and pretty new. Never really seen any probs with scale, but it's worth a look at this stage!

Cheers mate.

 

[DP]

No scale in Glasgow, so no need to look.

 

[martyndc88]

Thanks Martin,

System is in Glasgow and pretty new. Never really seen any probs with scale, but it's worth a look at this stage!

Cheers mate.

check that air vent on top of pump is open, and all other air vents in boiler, when its fixed let us know what it was

 

[Gary67]

UPDATE

Removed pump head - everything looks fine. Impeller turning freely.

Removed the diverter valve actuator. That's working okay. The exposed valve pin is moving freely manually.

Automatic air vent on the pump can be heard venting upon system refill.

Interestingly, this Vokera has a 'combustion button' (to the right of the CH temp control) it fires up the burner for CO2 service reading. When I activate it the heating circulates, and heats all the radiators, but when I deactivate the combustion mode and try to return to the regular CH mode, the burner is very briefly firing up, but not circulating water, before cutting out.

So the system CAN circulate, but doesn't seem to want to. Problem on the PCB? Why no circulation?

Many thanks for yuor help lads.

 

[nickso]

swap the thermistors over and see if it works then. not unknown for thermistors to throw up odd faults on these.

you can check the circulation by removing the diverter motor and turning a tap on, the boiler will fire at full rate because the dhw thermistor will be stone cold so don't wander off and leave it to possibly overheat.

 

[Gary67]

Ran thru a load of checks with Vokera tech dept today.

He believes it to be a fault in the PCB, based on the fact the pump is turning, the diverter is actuating but the fan/burner doesn't kick in.

Will let you know if new PCB solves the problem.

 

[Sloop]

check ch temp control knob may be broken,common fault on lineas?

 

[Gary67]

PROBLEM RESOLVED

Replaced PCB and the boiler is now functioning properly.

It's probably the last thing you'd want to change ££££, but having checked that everything else was ok, it's a case of £120 for a new one, and hold yer breath it works!

Only have to persuade the customer that changing a radiator wouldnt have fried her PCB now!

LESSON LEARNED: Before touching a boiler, make sure it's fully functioning before you get your tools out the van, or prepair to get stung!

Thanks to all those who helped.