Keston Questions (noise and flue options)

Paid a visit to the homebuilding and renovating show at Bath and West show ground yesterday (sat - also on today 30/11/03).

Bloke on the Eco-hometec stand said if you can't afford one of ours then given choice of Valliant thermocompact or Keston Celsius get the Keston.

In the Keston documentation there is a sentence (underlined) that says consider the possibility of the noise if installing near to a living area. Can anyone with a Keston comment on this ?.

Flue options - the best place (for boiler) is under the stairs (only 6 feet from the 3/4 inch iron gas pipe supplying the kitchen) and the flue can follow the underside of the stairs then go horizontally towards rear of kitchen and follow the 110 waste water stack up the loft, then either up to the ridge or out and down through the soffits.

Why can't I connect it to the waste stack ?. - i.e. well above the 'high tide mark' ?

Reply to
Andrew
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In article , Andrew writes

They seem like be a nice bunch, I spoke to them a bit before deciding that I couldn't justify the extra cost of their (excellent) boiler. I chose the Keston.

I have it in the corner of my kitchen and do not consider it to be excessively noisy, but this is a long way away from the main kitchen action. It does have a powerful flue fan which is noticeable and could be obtrusive in a quieter area. I will be boxing mine in the long term.

They want the intake and exhaust flues to be balanced, that means running two 50mm uPVC pipes to your chosen exit point. Roof line sounds good, but be aware that you are not allowed dips in the route - soffit might be ok. Inlet & exhaust need to be separated by 200mm. Check out the pdf downloads at:

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Reply to
fred

ROTFL!

You may have had a genteel upbringing and never participated in a 'light the fart' experiment in your teens.

Waste gasses both directly from humans and indirectly from decaying waste material such as in drains contain methane which is inflammable.

You migth get a blowback in the toilets etc

Bob

Reply to
Bob Minchin

Are you sure? The advantage of twin flues is that the exhaust and air feed can be in very different locations. The two pipes don't have to be near each other or the sae length. For e.g, the exhaust run up to a ridge tile and the air intake under the floor and penetrating the walls at low level.

Reply to
IMM

In theory this sounds fine. But, the stack is open so air is drawn in to prevent suction as large volumes of water go down the waste (like a bath emptying along with the washing machine and dishwasher). Dragging toxic fumes into a sewer is rather naughty.

Reply to
IMM

Maybe I should rephrase that - why can't I convert the top section of the waste stack so that the 2" mupvc flue enters at 1st floor ceiling height and exits up through the roof *inside* the waste stack.That way the flue terminal pokes out above the stack by say 6 inches and the remaining cross section is still used to vent the stack. Since we are only discharging acidic steam at this point where does the possibility of exploding methane come into it ?

Reply to
Andrew

Andrew,

There a number of options here. Firstly the waste pipe used for the exhaust of a Keston has to be mPVC, which is more heat resistant. You can put an air admittance valve on the top of the existing 110mm plastic stack in the loft. Then use the same hole in the roof to run the Keston exhaust. The existing hole maybe too big for the 2 to 2.5" exhaust pipe of the Keston. Then it may be wise to use mPVC 110mm pipe for the section that runs through the roof tiles. A bird guard must be fitted on the top of the 110mm pipe. Then you have no need to go outside on the roof. The air intake can be terminated at the eves.

Or remove the stack completly and use hepVO drain traps on all the upstairs appliances. see:

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and click on HepVO.

Good thinking Andrew. I never ROFLed

Reply to
IMM

It's pretty much academic.

If you download the Keston installation manual, you will find that it refers to specific British standards on where flues may run and be located, and adds some manufacturer specific options, which the regulations allow.

If you want to do something different, then it would be advisable to contact the manufacturer's technical department.

.andy

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Reply to
Andy Hall

In article , IMM writes

If the air intake is taken to an external wall and the exhaust to the roof ridge then there is a danger of wind pressure imbalancing the flue. I agree that if the intake air was taken from a wind neutral space, say underfloor, then that argument would be voided, but Keston specifically state that taking air from underfloor (or not from outside) will void the warranty. I assume that they are concerned about intake of dust etc into the combustion space and resulting damage.

Through necessity, my own intake & flueing arrangements are somewhat unusual, but I am not prepared to pass it on as a model for general consumption.

By contrast, the Eco Hometec guys are quite happy with you taking the inlet from neutral airspace and suggested to me that I could take intake from an unused but vented chimney which could then house a flexible liner for the exhaust. The difference in system cost however was IIRC

600-800quid.
Reply to
fred

Ok that gives me a better picture. Is there anything to stop drain sourced methane falling down the boiler flue (when it is not lit) and getting into the combustion chamber? I'm not familiar with keston boilers.. As someone else has suggested, the manufacturer might be able to help. Doesn't heating come under bldg regs now? How about asking the council technical services people who are usually most helpful?

Bob

Reply to
Bob Minchin

So little it is not worth considering. "most" twin pipes systems can have exhaust and air intake in different locations, that one of the clear advantages of twin pipes.

underfloor,

I didn't say take the air from the airspace under the floor. This would drag very cold air under the floor cooling the house, the same with taking it from a vented loft space too (this is silly as insulation dust could be dragged in.

Reply to
IMM

The instructions for my Celcius 25 say a 'minimum' of 200mm, and explicitly state no maximum distance. I also recall something about not being permitted on opposite sides of a building but I can't find that now -- it might have been in the instructions of a different boiler I was considering at the time.

Reply to
Andrew Gabriel

I've just moved into a house with a Keston K130 installed on the outside wall of a large airing cupboard (constructed of plasterboard) on the middle floor of 3. I wouldnt want to try to sleep in the room next to it and it's easily audible from the room above. It is a LOT noisier than the gloworm combi i had in my last place. We're going think about adding some sound insulation to the airing cupboard. Our manual recommends against attaching to partition walls.

I've no comparison to other condensing boilers so this may be typical and mine is a different model to the Celsius so YMMV.

Reply to
anthony james

In article , anthony james writes

I've recently got a Celsius 25 in the kitchen and I think it's extremely quiet; I was worried by that statement in the instructions as well.

You can tell it's running when on "full burn", on lower speeds you have to look at the indicators to tell if it's on or not. Even on full throttle it makes about the same noise as the fridge. I wouldn't worry about it.

Reply to
Tim Mitchell

It is in there somewhere - I suspect that because terminals on opposite side of the building are explicitly forbidden in the regs. I also suspect that having an instruction which is directly opposite to the regs would cause much confusion and would have casued a great deal of problems getting [Gas Council] type approval.

The OP should note that for a long rise (over 4m) on the flue a seperate drain and trap should be provided for condensate at the bottom of the ascent.

My own C25 takes air from a passage way under the house and terminates vertically through the (flat) roof.

I've yet to see the plume as the boiler is only on when someone's having a bath (reheating the cylinder) or for odd quater-hours here and there.

Reply to
Ed Sirett

The C130 is much a bigger and noisier boiler and a susperceded model. My own Celsius 25 is in a cupboard on the landing and I can't tell whether it is going or not - even for the first minute when it goes flat out.

Reply to
Ed Sirett

So what do you use for space heating ? - just curious. £800 for a Keston is an expensive way of heating water.

Reply to
Andrew

This is fairly typical behaviour with a modulating boiler.

For example, this Keston model drops its power level down to 7kW - I have a different make which will drop as low as 3-4kW.

During a large part of the year, spring and autumn, and during the day through he winter, the amount of heat required is much less than the full output of the boiler. With a conventional boiler, the burner is turned on and off to reduce the average heat output. In the case of most types of condensing boiler, the burner power is reduced which reduces output and water temperature.

It is more efficient to reduce power than to start and stop the burner. Moreover, reducing the temperature increases the boiler efficiency as it is pushed further into condensing operation.

.andy

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Reply to
Andy Hall

Depends on the burner design. A highly efficient spot rated burner (non-modulating) coupled to a heat bank can be very efficient overall.

Many top end developers are fitting Myson Kickspace heaters in kitchens. These require a high temperature flow for efficient draught free operation. The solution used to be an integrated thermal store as it provides 75-80C temps and a spot rated burner boiler always set to max temp. The efficiency was good as the burner was highly efficient with design maximised for a set rate.

Condensing boilers have advanced recently so now some approach it.. A DHW only heat bank with one high temp circuit taken off the heat bank for the Myson(s) and the CH circuit left to modulate on a condensing boiler. When the heat bank requires heat the boiler runs up to full temp. When back on CH it is left to modulate.

Reply to
IMM

Ok, but that's a different game. The background was a more conventional system.

Presumably this is to save wall space that would otherwise be needed for a radiator.........

We had one of these (actually a wall mount version) in a previous house to heat a stairwell and landing. It was effective but pretty noisy. I wouldn't have wanted it in the kitchen...

Wouldn't the main point be to get enough heat output?

I see what you're saying but it sounds like a lot of extra complexity

- presumably an extra pump for the Myson circuit??

.andy

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Reply to
Andy Hall

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