Hot water/Megaflow and pressure

[fuzzy-logic]

hi - just about to embark on a loft conversion whihc will include a new shower unit in the loft (so 2nd floor). I have a bathroom and shower on the gnd floor. I've been thinking about going with a megaflow to avoid pumps etc. but i'm not sure what else I need to consider. Will I need to increase the mains water pressure? by getting a larger feed (25mm) to my boundary? is it necessary for a megaflow? can someone tell me the difference between direct and indirect megaflow? where does the megaflow tank need to be situated in my setup? and is it a good idea in the first place? !!

thanks

[Andy Hall]

That would be difficult. The only way to increase pressure is with a pump and accumulating vessel.

That might increase flow rate. It won't increase pressure.

You can measure the flow rate at the kitchen tap by timing filling of a bucket. Generally at least 20litres/min should be regarded as required for a pressurised HW system.

It may be, subject to floor loading restrictions and water flow availability.

[David Hansen]

On Mon, 10 Sep 2007 02:05:11 -0700 someone who may be [e-mail] wrote this:-

Do you have a header tank for the heating system? Where is it located? How is the loft conversion to be heated?

Does the existing hot water cylinder have enough capacity to supply an additional bathroom? How rapidly does it recover? Are you unhappy with the existing hot water system?

Do you want high pressure hot (and presumably cold) water everywhere? If so, why?

Could you perhaps use a thermal store, which provides high pressure hot water without the expense of annual inspections on the pressure vessel?

Have you considered a Venturi shower?

Have you considered the life-cycle cost of a pressurised hot water cylinder (annual inspection and all) with the life-cycle cost of a pump? Both will provide much the same shower.

[Doctor Drivel]

Good points.

[robgraham]

hostel) where there were Megaflows. Neither owner knew that annual inspections were necessary; is this government mandatory or a requirement of the house insurers ?

Rob

[Jim Alexander]

An "annual inspection of the pressure vessel" is not (read my words) a requirement in a domestic installation. Perhaps you are alluding to testing of the safety devices which can be undertaken with a degree of competence.

Jim A

[Doctor Drivel]

All makers say so. Testing of the pressure devices is specialist job and not one for the average householder.

Have a burst or explosion, and the checks were not done then see if an insurer will pay out. They will tell you to refer to the makers instructions. Much the same as a car. If you don't have it serviced and the wheel drops off they don't want to know.

[fuzzy-logic]

all - I am a complete novice at this so please excuse any descriptions:

I have a hot water cylinder on the first floor above which there is a cold water tank. The loft is above this as will be the shower room.

I want to avoid the noise of a pump and ensure enough water to both showers. I guess flow rate is not that important then? We will want gas central heating in the loft and currently have a potterton gas boiler on the gnd floor.

All I am looking for is a good supply of hot water with no-one being scolded when they turn on the cold water somewhere else. I don't need a fast flow but thought it was necessary for getting water to the loft.

The hot water cylinder is not really big enough for a bath and a shower and it does take quite a while - over an hour- to have enough hot water to do anything with after a bath.

If I was to take everything out and start from scratch what solution would be recommended? it's an average Victorian semi . Thx again

[David Hansen]

On Mon, 10 Sep 2007 11:03:09 GMT someone who may be "Jim Alexander" wrote this:-

An annual insurance inspection, as would be done on say a high pressure boiler, is not a requirement.

It is not permitted for householders to do this inspection, unless they hold the relevant bits of paper.

[David Hansen]

On Mon, 10 Sep 2007 03:53:49 -0700 someone who may be robgraham wrote this:-

Yes it is.

They will undoubtedly wish not to pay out money if the necessary inspections have not been done.

[David Hansen]

On Mon, 10 Sep 2007 04:27:01 -0700 someone who may be [e-mail] wrote this:-

Is this mounted directly on top of the cylinder, or in the loft?

Have you considered the noise mains pressure water tends to make? This noise won't just be when showering.

Adopting a particular design of hot water cylinder does not affect how much hot water it holds compared to your current one. An "unvented" cylinder, such as the Megaflow, is not magic and it will not hold more hot water then an equivalent volume unvented one.

Flow rate is not too important, even for two showers. The question is whether the system can deal with the kitchen tap, bath and one shower in operation at the same time.

Is there a header tank for your existing heating system?

The size of the hot water storage cylinder is the key to achieving this.

Thermostatic fittings minimise these risks.

Sounds like a rather old cylinder, probably somewhat furred up. Do you live in a hard water area?

Including taking your existing radiators out?

[Jim Alexander]

Care to quote the statute?

Jim A

[Doctor Drivel]

The noise is far, far less than a power shower pump. Pipework properly installed with eliminate/reduce mains water noises.

I would get the main upratwed if need be and install:

1. A heat bank with a simple boiler. Smart CH pump and TRVs on all rads.
2. An complete one-box package of say: ACV HeatMaster, Atmos Multi, Gledhill Gulfstream - these can have smart pumps installed for CH. Or a Viesssmann

333, which heats the CH directly, so slightly different than the prior boilers.

1. Two Atmos Intercombis (the most simple and reliable boilers on the market). One doing upstairs CH one down. One dowing one bathroom, one the lother, combine the outlets for baths to give a flowrate of 24 litres/min.

[Doctor Drivel]

G3.

[Jim Alexander]

sorry that's not a statute

[Doctor Drivel]

[Jim Alexander]

Good link but only relevant to the installation work. My point was about maintenance. Not been answered yet.

Jim A

>

[David Hansen]

On Mon, 10 Sep 2007 12:28:02 GMT someone who may be "Jim Alexander" wrote this:-

If you think I have the time to grind through the pile of crap that is the Scottish Building Standards Agency web site you are mistaken.

[David Hansen]

On Mon, 10 Sep 2007 13:37:29 +0100 someone who may be "Doctor Drivel" wrote this:-

That depends on the particular circumstances.

The noise from pumps can be eliminated/reduced with careful design too.

[Jim Alexander]

But there is no need to do *that*. These are relevent to installation work, not maintenance work.

Your point was that "It is not permitted for householders to do this inspection, unless they hold the relevant bits of paper". I suggested otherwise and my point has not yet been countered, though at this time your compatriate DD is beavering away at least trying to defend what was *your* point.

Jim A