megaflo hot water and heating system with tanks in the loft

[gddixon]

Hi All and thanks for looking,

I'm having the loft converted in our semi-detached in Guildford, Surrey. It'll end up being the largest room in the house. I'm putting an en suite shower room up there too, directly above the current bathroom - that also houses the hot water tank.

I've been thinking of changing our current batheroom in any case, and the water system with it, and the loft conversion company mentioned installing a megaflo system with direct pressure from the mains and storage tanks concealed around the eaves of the loft.

Has anyone on this board:

a) Ever done this successfully b) Any knowledge of the flow rate required - my in-laws have direct mains pressure feeds and their flow rate is the same as mine (around

18 lpm) c) Any idea of the cost of altering the mains to increase the flow d) Any recommendations for manufacturer of megaflo systems

cheers

Gaz

[Doctor Drivel]

Megaflows require an annual service and can explode. Fit a heat bank (thermal store). No tanks just a cylinder off the mains. Explanation is here:

companies make them. The Range Flowmax is good.

[Chas]

I have had a look at the heatweb link you posted but cannot find any reference to the Megaflow brand exploding. I have clearly missed somthing here, can you be a bit more precise in your link. Thanks.

[Ed Sirett]

Yes (me).

Good do a lot better. If the incomer is the original lead or even 20mm plastic then an upgrade is called for.

How long is a piece of string. Depends on length, ground and access. Not less than several hundred.

Well genuine Megaflo's are by Heatrae Sadia. Albion, Telford, Ariston, Santon are worth a look.

Oh, and there are not legal to fit unless you hold a G3 ticket.

[Doctor Drivel]

It will cost you min' £60 to service per ann.

can take down the side of a house.

The DPS Pandora does not even need an overflow or discharge pipe.

[Doctor Drivel]

And expensive too.

[John Stumbles]

Maybe you should look for someone who understands the technology then: if you did go for a Megaflo (or other make of unvented DHW system) then you wouldn't need a storage tank - let alone tanks, plural.

[Chas]

This link has taken me to a site that has deliberatly removed/plugged all safety devices and contrived an explosion. In your previous post you infer that heatweb say that Megaflow tanks can explode, I cannot find the reference to this. What have I missed?

[Anita Palley]

quoted text -

There may be a teensy weensy bit of scaremongering going on. For some reason this group seems to have very emotive responses to the discussion of pretty mundane hot-water and heating systems, with vehement and implacable postions being adopted.

This thread is likely to collapse imminently into a slanging match. Just thank god you didn't suggest installing a combi.

[John Rumm]

You might also get struck by lightening - probably just as likely.

If you cut your break line and drive fast at a wall you could hurt yourself as well.

[John Rumm]

You would not really need any other storage tanks with a mains pressure water system.

You could also look at a thermal store as well:

b) Any knowledge of the flow rate required - my in-laws have direct

That sounds a bit on the low side for ideal performance - but might just hack it depending on your usage.

Starting at half a k upwards probably.

[gddixon]

Thanks for all your responses. This has set me on the way. I appreciate all the links.

cheers

Gaz

[The Natural Philosopher]

Tanks? only need ONE..

yes

? if you have pressure flow rate is down to pipe sizes mainly. NMake sure you use 22mm almost everywhere.

almost all are good. Get one with a good guarantee and stainless.

Total cost to pressurize the boiler and install the tank should be around 1500 notes or so.,

[The Natural Philosopher]

several years of doctor drivel's drivel.

He is killfiled by most regulars unless they feel like engaging in amusing argument that leads bowehgere.

Drivel knows a lot of things. Sadly none of them are factual, and most come out of glossy catalogues.

The consensus is that he is mentally unstable, and has a fixation about plumbing, and the nurses give him access to a computer and plumbing catalogues to keep him quiet, when the medication necessary to remove the conviction that he is Bob the Builder cut in.

[The Natural Philosopher]

Or even Brake line..

[David Hansen]

On Sat, 27 Oct 2007 14:14:24 -0700 someone who may be [e-mail] wrote this:-

As the others have said, the loft conversion company are probably not too au fait with plumbing.

If you do want to minimise the number of storage tanks and have mains pressure hot and cold water everywhere then the approach to consider is a thermal store with a built in header tank for the heating system, including the store. This is in many ways the best of both worlds and has few downsides.

If you live in a hard water area the type of store with external heat exchangers would be essential.

[Dave Plowman (News)]

Pot, kettle. ;-)

[John Rumm]

Sadly probably true, although if a company specialises in loft conversions, you would expect that this would be one area it really ought to have expertise in...

[David Hansen]

On Sat, 27 Oct 2007 16:17:33 -0700 someone who may be Chas wrote this:-

I have no idea which brand was involved, but ISTR it was an "unvented" system which exploded in the case outlined in

though I would not argue against such systems from this and other cases. Provided they are looked after properly such systems are acceptably safe, though I wouldn't want one where large volumes of water could pour on anyone below.

Vented systems can also explode, or indeed collapse, though they are more forgiving and they are less likely to cause as much damage if it does happen.

As for thermal stores the two on the right in the photograph on

have header tanks built into the top of the unit. This would be the only header tank you would need and it would feed the heating as well as the thermal store. As long as this is above the highest radiator there will be no problem. Cold and hot water would be at mains pressure, so your en suite shower would work fine.

[Doctor Drivel]

charge.