plumes from Vaillant 622/2E System boiler

[Peter]

Hello,

I am having a Vaillant 622/2E System boiler installed in my house for central heating and hot water.

Because of the way our house sits on a hill any plume from the flue outlet would be comming out just to the left and below the main house door entrance and also quite near a hall window. i.e. any plume would be very visible.

Can anyone tell me how much plume I should expect to see ? In cold weather would I expect to see a plume all day, or just when the boiler is starting in the morning ? Would there be a plume in summer ?

I am asking as I have the option (for a bit more money) to run the flue from the current planned outlet vertically up the outside side of the house and through the soffit terminating above the roof. I like this solution on terms of hiding the plumes but my architect says the flue will look ugly on the side of the house.

I have checked with Vaillant and the wall solution would not exceed any permissable lengths so there is no problem with doing this. I just don't know if it's worth it or not ?

Also, anybody had any problems with either any of the following:- Vaillant EcoMax 622/2E Megaflo HE CL210 Indirect Cylinders

Many thanks for any feedback/help

Pete

[Christian McArdle]

My Ideal Icos plumed any time it was on. It would certainly be better if the flue terminal had been above the roof line.

Not directly, but I hear it is good.

My parents have a Megaflo. It is excellent. 210 litres is seriously large, enough to run two full baths simultaneously even with the boiler off. Are you sure you need that much?

Christian.

[Andrew Gabriel]

I think it might depend on the boiler and flue. My Keston doesn't produce anywhere near as much as I thought it might, actually, probably not a lot more than next door's conventional boiler.

All day, when boiler is firing.

Mine doesn't plume when it starts up -- I think when the heat exchanger is cold, all the condensate it trapped before leaving the flue.

Don't know -- only run mine in Winter (it doesn't do the hot water).

[IMM]

That is because it is a top mounted burner with a bottom flue. The condensate trap is taken off the lowest point of the flue. This mean that less moisture is in the flue gasses as it exhausts. Have a Keston with the maximum flue length of 40 or 50 metres, or whatever, and virtually no plume is visible, if at all.

I have a bottom mounted burner and top mounted flue. The flues gas are full of moisture when exhausting giving a thick plume.

In the early days of condensing boilers the top mounted flue jobs didn't produce much condensate in the drain pipe, with plumbers saying "condensing boilers don't work", "the makers have played around with the burnmers to make that plume", "not worth the money", etc. The test efficiencies tended to right over their gutter fitting heads.

My top monted flue does plume in summer.

[IMM]

The size could be dropped by 40% if a quick recovery coil and a hot water priority system is used. The Vaillant is quite powerful and should re-heat very quickly. It would be re-heating as water is being drawn-off, in effect making the cylinder larger.

A better method is to have a hot water priority system, have an extra high limit stat set to 90-95C and a flow switch on the hot pipe that serves only the baths and showers, which are the largest hot water users. When any bath or shower is switched on the boiler automatically fires, by-passing the run stat set to 55C and controlled by the high limit stat, sending heat to the cylinder. When the bath or shower taps are off it reverts back to the run stat of 55C. This is a cheap and very effective method by using the full power of the boiler available using only an extra flow switch and cylinder stat. The boiler power is there so use it. It can be sued to reduce the cost of other equipment, reduce space taken up and reduce costs. This can be implemented on virtually any system.

[Lobster]

Yes the plume is visible the whole time the boiler's working, summer and winter; obviously it comes and goes when the thermostat kicks in and out. It tends to blow around a lot when it's windy. When we first had ours put in it reminded us of the set of sci-fi movie like Bladerunner or something. But you get used to it. Just think of the money you're saving because it's cool (and therefore visible!) Only you can decide whether it's more or less ugly than a flue attached to the side of the house.

We have an EcoMax 226/EH (don't know how close that is to yours) which we like. Only problem in 2-3 years has been a failed combustion fan (~100 quid) which somebody on this ng reckoned was a design flaw, because the fans aren't designed for temperature extremes.

HTH David