Pumping hot water upstairs

[Mike Harrison]

Situation : House with downstairs bathroom, cold and hot water (from central heating) tanks are on ground floor. Wanting to add an upstairs en-suite bathroom, the problem is how to get hot water upstairs. One solution would be to move the HW tank upstairs (presumably this could be fed from mains), but this entails lots of plumbing of central-heating feed to it.

Can you buy a pump/pressure switch type system that automatically turns on when the upstairs hot tap is opened to pump the hot water up....

I'm envisaging something like a pump (with non-return valve), and maybe a small 'air reservoir' type arrangement (as used on sealed CH systems) to make the volume/pressure behaviour 'softer', so the pump maintains a positive pressure in the pipe/resevrvoir, and the pressure drop when the tap is opened turns the pump on, and the rise created by the pump acting against the closed tap turns it off. I'd guess adjustment may be tricky to stop it oscillating on/off....

Anyone know of a system to do this...

[Steve Firth]

Err, you don't have to move the hotwater cylinder, just the header tank for the hot water system. So you don't have to rearrange the supply tot he hot water cylinder, indeed you don't have to move the HW cylinder at all. Just make sure that either (a) the cold water tank is higher than the taps in the bathroom or (b) that you have a sealed (mains pressure) system.

[Mike Harrison]

I've now had a look at the system, figured out how it works, and come to the same conclusion, i.e. move the cold water tank to the loft. However there is a problem - the access to the loft is only about 1x2ft. So does anyone know anyone who makes something like a collapsible water tank - mabe made of floppy polythene that is made rigid by a frame....?? Or do I have to connect lots of little tanks together..?

...and how do you determine how big the cold tank needs to be - instinct tells me it should be bigger than the hot water cylinder, but I suppose it depends how fast it fills....?

[Ian Clowes]

same conclusion, i.e.

to the loft is only

mabe made of floppy

The round ones collapse pretty well. They don't have a frame. The water pops them back into shape.

me it should be

50 gal is normal. How big is the current one?

HTH IanC

[John Stumbles]

tanks are on ground floor.

hot water upstairs.

be fed from mains), but

when the upstairs hot tap

small 'air reservoir' type

behaviour 'softer', so the

pressure drop when the tap is

the closed tap turns it

Negative head pump (ask Google)

-- John Stumbles

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-+ Women always generalise

[Christian McArdle]

Don't write off the mains pressure systems. You may actually find it less work (or cheaper if paying someone) to install a mains pressure hot water cylinder of some sort and not bother sticking anything in the loft. Either a mains pressure unvented cylinder or some form of heat bank would achieve this. Purchase costs are about 600+VAT for either, plus fitting. However, if your mains water supply is good enough, these will be vastly superior to a gravity fed system. If your hot water cylinder is old, it might need replacing soon anyway.

Christian.

[Mike Harrison]

Can you suggest any sources of info on what's involved in doing this ? (Will visit the Library later today...) I vaguely remember reading somewhere that pressurised HW systems now come under building regs and must be installed by a registered plumber. This is a DIY and 'do it cheaply' job to turn a room that's too small to call a

3rd bedroom into an ensuite bathroom to improve value for selling the house next year.

[Andy Hall]

visit the Library later

building regs and

3rd bedroom into an

In fact they all come under Building Regulations now.

For pressurised cylinders installation the issue is safety and is covered by part G.

For all cylinders, conservation of energy applies and is covered by part L1.

you use contractors who are members of the appropriate organisations (e.g. IoP), then they can self certify and issue a certificate. Alternatively you can submit a building notice.

Especially considering that you are selling the house, it would be prudent to do things by the book and do the necessary applications if you plan to DIY.

As a side note, are you sure that reducing the number of rooms will improve the value? You may think that a room is too small to be called a bedroom but the standards for the minimum size of a bedroom, especially for a child, are for quite surprisingly small. Creating a two bedroomed house (albeit with an en-suite may result in a lower value than a three bedroomed house or make it difficult to sell. I would contact a couple of local estate agents and get a view from them.

.andy

To email, substitute .nospam with .gl

[Christian McArdle]

For DIY, and at the risk of sounding like IMM, a heat bank might be more appropriate than an unvented cylinder if you intend to do it yourself. In this design, the water within the cylinder is stored unpressurised with inhibitor, making them inherently safer and not requiring all the safety features needed by unvented cylinders.

To install is very simple. In fact, they are much simpler than a conventional gravity cylinder to install. The indirect heating coil is connected up, just like the conventional gravity cylinder. It requires pumped flow, not gravity circulation. The cylinder stat is connected up as before. It needs an electricity supply from the central heating circuit (but not switched by a programmer). You provide a mains pressure water feed, and out comes mains pressure water the other end. All the complex feed and venting arrangements and loft tanks can be removed, making it ideal for showers in loft conversions, which are impossible to feed using gravity fed systems.

If you convert the hot water to mains pressure, you should do the same for your cold taps. Otherwise, your mixers (i.e. showers) will be unbalanced and difficult to control. Also, people might be disturbed if the basin or bath taps get a trickle from the cold tap and a torrent from the hot tap.

Before you consider this, you must be sure that your mains water supply is good so that you get good flow and pressure at your kitchen tap.

Christian.

[Mike Harrison]

visit the Library later

under building regs and

a 3rd bedroom into an

But presumably there is no building regs requirement if all I do is move the cold tank to the loft, not touching the hot system except to raise the vent pipe to the level of the cold tank and take a feed off for the new bathroom.

This was the advice of an estate agent. As well as being small and a silly shape, the third room is only accessible off another bedroom.

[Andy Hall]

It would still be subject to part L1 requirements, I suspect. Considering that the water is stored at 75-80 degrees as opposed to

60, for a given amount of insulation the heat loss would be higher as well....

.andy

To email, substitute .nospam with .gl

[Christian McArdle]

I think you are right.

However, building regulations approval for replacing a cylinder will be very cheap and simple. It only relates to certifying that there is sufficient insulation on the cylinder (it will have a "Part L" certificate on the side) and that there is a cylinder thermostat capable of turning off the boiler when it is fully heated. It is nothing to be scared of and doesn't require a certified person to install.

The building control officers are usually very nice people and, quite frankly, won't really care about what you do, as they are far more interested in telling people how far to dig their foundations, or to replace their joists with ones half an inch wider.

That will probably make it worthwhile. No-one likes a 2+1, at least no-one actually looking for a 3 bed. Reminds me of one house I looked at which was described as a 3 bed, but one room just consisted of what could be described as a particularly wide corridor upstairs. I wouldn't have even described it as a 2+1. Certainly no scope even as an en-suite.

Christian.

[Christian McArdle]

But then, it stores more heat. The losses due to temperature difference will be approximately proportional to the temperature rise.

Losses due to the larger cylinder at lower temperature will be approximately sqrt x in nature assuming a sphere, which is better. However, most cylinders maintain a constant diameter (450mm) and vary in height. This then puts the capacity vs loss curve back towards a linear footing.

In all, I suspect a heat bank of similar thermal capacity is probably fractionally worse than an equivalent cylinder. However, modern insulation means this is easily good enough.

In any case, I'm sure it would be subject to Part L1. At least, I would hope so.

Christian.

[Mike Harrison]

Thanks for the info - as this is a 'minimum cost' install, and the present GCH system is on the old side, and seems to be somewhat confusingly set up, I think the option of changing as little as possible and just moving the cold tank to the loft will be the cheapest and easiest (even if we have to hack out a bigger loft hatch or connect several small CW tanks!), It also frees up some potentially useable space under the stairs (where the CW tank is now), and would allow a bigger HW tank to be installed in the future (to allow 2 baths to be run off 1 tank!) if desired.

..but there is also the issue of building permission application fees - I think it's well over 100 quid in the borough concerned (Walthem Forest) - not sure if this applies to all types of work, but was certainly the case when we were investigating DIYing window replacement.

[James]

think it's well over 100

to all types of work, but

replacement.

This is problem now that building regulations are extending into relatively trivial areas. A year or so ago the cost of building regulations approval for replacing a cylinder here was about 190 pounds - the same as employing someone to do the complete job!! (The fees were on a sliding scale - and that represented the minimum fee).

[Steve Firth]

So what happens if one has a gravity fed HW system?

[Christian McArdle]

They are basically banned. (Assuming you mean gravity circulated indirect heating). Oviously, you don't have to bring an existing system up to date until replacement is needed.

Christian.

[Owain]

"Christian McArdle" wrote | >So what happens if one has a gravity fed HW system? | They are basically banned. (Assuming you mean gravity circulated | indirect heating).

So what does one do in the case of solid fuel boilers which can't be shut down totally?

Owain

[Christian McArdle]

Solid fuel boilers are exempt.

i.e. it says

| Timing systems would be inappropriate for systems with solid fuel | boilers which operate only by natural draught.

The requirement for a hot water cylinder thermostat to operate a boiler interlock comes under a paragraph refering only to gas and oil systems.

| Gas and oil fired hot water central heating system controls should | switch the boiler off when no heat is required whether control is by | room thermostats or by thermostatic radiator valves: | | a) The boiler in systems controlled by thermostats should operate | only when a space heating or vessel thermostat is calling for heat.

As far as pumped primary circuits are concerned, it indicates using pumped primaries as a method of complying for the requirement to reduce primary circuit losses. However, it isn't an absolute requirement. I suspect you would need to lag the primary circuit to reduce losses if the pipes will remain hot for long periods. That might have difficulty establishing gravity flow, though, as it might affect the thermal characteristics of the circuit. I don't know how this rule would be interpreted in practice.

Christian.

[Steve Firth]

How absolutely absurd.

Why should it be banned at all? It's a way of making efficient use of a solid fuel room heater. Are those banned as well?