Vokera 20-80 ES Flowmatic goes out in wind

[andyv1]

My combi boiler periodically refuses to heat up when it's windy. My house is right on the coast with the vent sticking out of the wall on the 2nd floor, so the last couple of days have been problematical. Once the weather is OK it acts normally and relights automatically.

I know that there are built in safeguards to protect the boiler, and others have recommended a servicing, but this was done not that long ago and the problem remains.

It seems to me that some people have got round this by installing some sort of windshield to stop the wind blowing directly into the flue. Right now I've got scaffolding up as there's some other work going on on the roof so it seems an ideal time to deal with this. Climbing a ladder is not an option.

Can anybody advise?

 

[DP]

I know that there are built in safeguards to protect the boiler, and others have recommended a servicing, but this was done not that long ago and the problem remains.

Not a service I assure you. A make believe service but not what the boiler needs. It is playing up because a service is well overdue.

It seems to me that some people have got round this by installing some sort of windshield to stop the wind blowing directly into the flue

Not required.

Can anybody advise?

Get a heating engineer (who knows what he is doing) to service the boiler. A service requires boiler parts to be taken out, cleaned. greased adjusted as required. To stich a FGA in the flue is not a service, nor is use of a feather duster to dust the boiler.

 

[Agile]

Just to add to what DP has said, fitting anything to the flue is not permitted by the manufacturer and can be potentially dangerous.

Tony

 

[andyv1]

Many thanks. It's kind of what I expected.

However I'm curious as to how the boiler works. I presume it's designed to withstand gusts of wind by having a fan which matches the wind pressure. Just how strong a wind will a well maintained boiler stand before it gives up?

 

[Agile]

No, its nothing like that!

The terminal is meant to be designed so that whatever the wind speed or angle the pressure between the inlet and outlet does not create a differential which might affect the inside of the boiler.

Tony

 

[andyv1]

As you can see it's a while since I posted on this topic. The problem remains as the boiler is in a house I only visit on the odd weekend so I've never got round to sorting it. However on the weekend of 23rd March it was very windy and the boiler wouldn't fire up, though the pilot light stayed alight.

Yesterday I went back and had a better look at it. It was working normally and had presumably started up of its own accird when the wind dropped.

It's a Vokera 20-80 RS boiler and I've examined the fan, the pressure switch and the plastic tube to the switch. The fan spins, the tube isn't perished and when I pull it off the flue pipe the switch clicks.

Can somebody explain the following points please?

In the previous answer Agile says that whatever the wind speed, the boiler is desgned to cope with this. To achieve this should the fan run at different speeds depending on the outside wind? Is there a way to test for this?

What then ultimately causes the boiler to go into shut down position?

I noticed that several of the speed nuts on the combustion chamber front panel were corroded and the self tapping screws weren't holding. Would it affect things if the chamber wasn't quite airtight?

I am going to get the boiler looked at properly but from what DP said I'm not convinced that it was done properly before, so I'd like a bit of background knowledge before I get told I need a new boiler.

 

[ianmcd]

Get an experienced Vokera engineer to look at this you are playing around with things that could become dangerous

 

[Agile]

A DIYer is not expected to open up the combustion chamber!

If you think forward from what I said you would realise that the fan runs at a constant speed.

Tony

 

[andyv1]

Thanks for the responses. I know gas appliances should only be serviced by qualified people, for obvious reasons, but I have had various experiences of people coming along and fitting random parts to my fridge, washing machine, TV, car etc that I try to at least get some idea of what's going on so I can judge whether they know what they are doing.

I'm still keen to know how the boiler compensates for strong winds. I now have to assume that normally the wind blows in equally strongly to the inner and outer parts of the flue. Having a fan running ensures that the exhaust is at a slightly higher pressure. It's some form of imbalance here that needs correcting.

 

[Agile]

The terminal is meant to be designed so that whatever the wind speed or angle the pressure between the inlet and outlet does not create a differential which might affect the inside of the boiler.

Thats the design objective and probably reasonably well achieved.

We suspect that the inside of your boiler has not been serviced to achieve the makers original performance!

Because its old it uses a pilot light which is highly inefficient use of gas and has been superceeded for the last 15 years by electronic ignition.

Many engineers are not very familiar with working on PP boilers because they never worked on them to any great extent.

In this case an older ex-BG person would usually be better with your model.

Its also essential that the case seals are in good order and the engineer will know how to test them.

I am also wondering if the fan has been cleaned and is running at low speed when the boiler is at rest.

Tony