Condensing Combi Flu

[Big Phil]

Hi, I've just bought a Vaillant Condensing combination boiler which I'm going to install in my loft. I've got a vertical flu to go through the ceiling, but the combi is to be mounted on the chimney breast in the loft so the flu will come up next to the stack, only about 250mm away from it.

In the instructions is says that the flu should be 500mm from a parallel wall (put doesn't say anything about a chimney). Does anyone know if this distance is to do with the operation of the flu or just because the fumes may discolour the wall, in which case it doesn't matter?

Also, do I need to fit a trap to the 19mm condensate drain before it connects to the sink waste in the bathroom?

Any assitance would be appreciated.

Thanks

Phil

[Ed Sirett]

You will need a couple of bends to move the flue away from the wall (chimney stack). You definately need a trap on the condensate drain, the trap however may already be built into the boiler.

[IMM]

I would say it doesn't mater at all, but contact Vaillant to be sure. If the stack is not being used, then why not divert the boilers flue into the stack and terminate the boilers flue at stack height. Then no roof tiles to take up. Then the condensing plume would be very effective to look at.

No. The boiler takes care of this.

[Big Phil]

Hmmm, I like the idea about taking the flu through the stack. It would look quite good wouldn't it. I'd be able to compete with next doors wood burning stove then!

Thanks for the info.

Phil

[IMM]

They do look good when belting out the plume. But the stack can't be used for a fire downstairs. I have seen a chimney breast taken out and the part in the loft left and a condensing flue run through.

[Andy Hall]

Roof venting for condensing boilers seems to be the method of choice in Germany, both for apartments and houses. I have not often seen much of a plume, though. Perhaps that's because the length of the flue results in the water vapour settling and running down and back into the boiler. With cold air being drawn down the outer section, there will be a chilling effect to the walls of the inner one.....

.andy

To email, substitute .nospam with .gl

[Christian McArdle]

Another problem is that the chimney pot needs to be replaced by the flue terminal or the flue terminal can stick out of the chimney pot, whichever you feel is aesthetically more pleasing.

Christian.

[IMM]

Stop it!! You will start Maxie off again.

[IMM]

I wouldn't call that a problem. Those I have seen have kept the pot with the boiler flue on visible from the ground.

[Christian McArdle]

I'd say it was a problem, but not an insurmountable one by any means.

Christian.

[geoff]

In message , IMM writes

Notice the difference between "method of choice" and "All homes in Germany"

or is this a step too far for you ?