Moving hot water cylinder, maybe into loft, maybe removing chimney

Sounds very cheap - I didn't even think you'd be able to get hold of a HWC that wasn't already foam insulated. I certainly doubt it conforms to Part L of the building regs in relation to energy efficiency.

a) A new high flow combi such as an Alpha CD50. b) A combination tank (Fortic) which has the hot cylinder and cold tank all in one and put in the loft. The combi can also go in the loft.

Russ, it ,must be ditched and proper stuff fitted.

Probably yes, as this will give you a better proportioned room and more space. However, removing the chimney breast in the room is the easy part

- the awkward part is supporting the chimney above, which will usually require a structural engineer's input. Such a job would be subject to Building Control.

If the chimney is against the shared wall in the semi it might not be possible to remove it depending on the arrangement of your and your neighbour's flues, and the Party Wall Act will apply.

You might want to consider carefully retaining the option to have a gas fire in the living room below, especially if you are likely to sell, as this is a "feature" liked by many buyers.

Owain

How predictable. From one where cost isn't a consideration.

That's what we thought, but...

I google-grouped for removing a chimney breat after I posted, and started to think it was a bad idea. (I'd already googled for moving HWC before I posted, which is why I posted - good advice and recommendations, but little indication of what is _worth_ the time/effort/money given the present system is working; little about the _disadvantages_ of mains pressure hot water, and no one saying how well a raised cold tank and HWC worked for them).

I was slightly worried about that - slightly worried about that room as a whole - but putting doors across it wasn't as drastic as ripping the chimney out would be.

Still totally undecided about the HWC.

Cheers, David.

P.S. I don't ask for advice on here and then do nothing - lots of electrical work and filling successfully carried out just before part P thanks to responses on here the other year!

Cost is certainly a consideration here! I'm thinking of moving the existing cylinder into the loft.

However, apart from the existing cylinder being of unknown quality and uninsulated (though it would be easy enough to add bags of insulation and a makeshift box for it in the loft), it make be more work to move it. Buying a new cylinder, putting it in the loft, getting all the pipe work in place, and _then_ just joining a few pipes on "D-day" sounds easier (and less likely to leave us without heating for days if it all goes wrong) than having to move the existing cylinder. I've only got to drop it or split it on that day, and we're stuffed. Without heating. In December!

The loft hatch is 63cm square, though to use all of that the built in step ladder would have to be removed (easy). Unfortunately, the roof line and supports would prevent me just lifting anything like a 60cm cylinder straight up, so I'll have to try with a cardbox box to see what will fit at an angle. Or use measurements and geometry.

How would I "distribute" the load. I've read that people try to distribute the load over as many rafters as possible, but our ceiling are (were) terrible, suggesting the rafters have little strength, so I'd rather try and put all the load onto/over the supporting wall. Is this practical?

Cheers, David.

Our HWC is a combination one (Cylinder and header tank in one) in the loft - no problems at all, although I wouldn't recommend a combination one as the cold water part tends to be a bit on the small side and has been known to run out during a bath - isn't too bad since I replaced the ballcock, but before that the water used to trickle in and it could take an hour to refill - no good it two baths in a row were needed!

You will find that the extra head you gain in lifting the header tank to fit the HWC in underneath will give you better showers and bath filling times I would imagine.

Bear in mind that leaving the chimney breast and removing the cupboards might offer you excellant opportunity for smaller cubpoards and/or shelving on either side of the breast.

Not a bad plan - you could get the immersion up and running and do the hot water changeover in advance, meaning you just have to change the heating plumbing over on "D-day".

My Wife suggested I should ask a plumber how much he would charge to do the job, since it might be cheaper than the time I would spend doing it myself (she's an optimist!).

He said simply that he wouldn't recommend it (though when pressed, is coming to look at the job more closely). He suggested a combi (until I said we had two bathrooms), or an unvented system with the tank elsewhere entirely (garage?). He also said there'd been a case where a faulty immersion heater on a HWC in a loft had melted the cold storage tank, which burst and killed the people in the bedroom below.

So now a plumber has said "putting everything in the loft is a BAD IDEA" my wife is dead against it.

A new system isn't totally out of the question - the current boiler is working but 25 years old. However, we'd intended to keep it until it died, and I hoped to keep a "standard" indirect gravity fed system (but in the loft) because it's a known quantity and can be DIYed if necessary.

btw, I've searched, but not found a good unvented vs heat store thread.

Any advice?

Cheers, David.

This "plumber" is an idiot. Avoid him.

Half truth. Only one was killed. What actually happened was not a faulty tank, but a faulty immersion heater in an entirely standard cylinder and tank arrangement. The water boiled and was delivered up into the roof tank which then eventually distorted/broke over the people in the bedroom below.

You can draw your own conclusions regarding the credibility of the plumber.

You could do either. A thermal store can be DIYed and the whole thing could go in the loft. These have a heat exchanger through which the cold mains water runs to be heated. The cylinder, which acts as the store, has an integrated header tank and the water in that is not under pressure. When you use HW, there is a pump which circulates water from the store through the heat exchanger. The water in the cylinder can either be heated directly by the boiler and effectively be associated with the primary circuit with the CH if it is all open vented, or you can have a coil in the cylinder and make that associated with the CH circuit and have that sealed - i.e. you then have three sets of water - the boiler/CH/cylinder coil; the cylinder store water and finally the mains water being heated.

These arrangements get around the professional installation restrictions imposed by the Buillding Regulations, because there is not a large volume of water under pressure.

An unvented cylinder does have to be installed professionally according to the Buillding Regulations.

With any mains fed system, do check the water pressure and flow at teh kitchen sink. If you are getting less than about 20 litres/min, a mains system is going to be disappointing in comparison to a tank based one.

Advantages of Heat-Banks (form of thermal store)

- Instant high pressure hot water - When the store has reached temperature water is delivered instantly at the taps.

- High mains water pressures - at up to 10 bar, compared to 3.5 bar with unvented cylinders.

- Very high water flow-rate - The high-end heat-banks have a flow-rate up to

- Long efficient boiler burn - Reduces boiler on-off cycling increasing efficiency, although inefficient boiler cycling is no longer a major problem with boilers with forced flues.

- Maintains optimum boiler temperature range - using a blending valve the flow/return of the boiler can be kept to opimum mainatinaing greater effciencies. The boiler operates at optimum performance.

- May combine the output of the stored water and the boiler

- Cylinder may be smaller for a similar performance - smaller cylinders than unvented cylinders.

- Cylinder at low pressure - Unlike an unvented cylinder it does not store water at high pressures.

- Fast cylinder recovery rate - When the boiler is connected directly to the heat-bank, and not via an indirect coil, the recovery rate is rapid. Although in some cases a boiler may heat the heat-bank via an indirect coil, reducing the recovery rate.

- Legionella bacteria virtually eliminated - The Legionella bacteria cannot survive in the high temperature sealed conditions of a heat-bank.

- No scale build-up in heat-bank - Containing primary and not secondary fresh water, there is no scale build-up inside the heat-bank.

- Cold water storage eliminated - No need for cold water storage tanks.

- Solar heating storage - Water heated via solar panels may be stored in the heat-bank via a solar coil.

- Easy maintenance - If an external plate heat exchanger requires cleaning or replacing it is a matter of draining down the heat-bank, or closing isolating vales, and unscrewing the plate heat-exchanger. In some rare instances plate heat-exchangers are fitted directly inside the heat-bank preventing on-site maintenance.

- Easy to improve hot water flowrates - By simply adding additional plate heat-exchangers in parallel, hot water flow rates may be improved. Retrofit additions are possible if extra bathrooms or showers are installed. This is impossible with unvented cylinders.

- Stored water vessel need not be cylindrical - As no internal coil is used for hot water heat transfer the stored water vessel may be any shape, as opposed to a thermal store which has to be cylindrical for maximum efficiency. This has advantages where space is limited.

Disadvantages of Heat-Banks

- The store needs be near fully temperature to supply baths - Before any hot water is drawn off, the store must be up to temperature. Many later versions use a blending valve on the return to the boiler to ensure only up to temperature water is pumped into the store by the boiler. This prevents agitation of the stored water, and aiding heat stratification within the store giving useful water at the top of the store within a short time. The water is heated only in one pass through the boiler.

- May not take full advantage of a condensing boiler - Maintaining the stored water at 75C to 80C results in a generally high boiler return temperature. This will not take full advantage of a condensing boiler, which increases in efficiency with lower return temperatures. With the superior heat stratification of taller cylinders this problem will be reduced. Condensing boilers with a wide operational flow and return temperature differential are best suited to thermal stores and heat banks. Overall efficiency with condensing boilers is still very, very good.

- Lower water temperatures with fast flow-rates - As with Combi boilers, fast flow-rates through the plate heat-exchanger results in lower water temperatures. This is not so pronounced with heat-banks as with thermal-stores. This also applies to combi's. With a heat bank, larger or extra plate heat exchangers can be fitted to increase flow rates. Sized up properly this is not an issue in operation.

- Needs more inhibior - A minor added cost.

Advantages mainly to heat banks.

Andy Hall wrote: [snip]

Oh pants. We're on our second plumber already. Our previous "plumber" charged a small fortune for small jobs, but (amazingly! ;-) ) was always available at short notice for emergencies! After =A3250 for a new rad which he hung at an angle, we said never again.

This new plumber came recommended, doesn't even have to advertise locally, and is always very busy - about 1/3rd the cost of the previous one too, so I was quite pleased to find him. Until now! Maybe he doesn't fancy lifting a tank into the loft. Or maybe he was backing up his story that it'll be difficult to support the cold tank properly in the loft, and giving this disaster as the worst thing that can happen. Anyway, thanks for the link to the story - I've printed it out to show my wife that we're being sold a false scare story here.

Thanks for all the information. I think we'll look again at the DIY option, though I'll probably leave it until warmer weather arrives. In the meantime I can still check out the mains pressure to see what our options are.

Cheers, David.

probably just resting on joists, and the thermostat wasn't BS marked. They'd also heard the water boiling before but done nothing about it - which seems madness given they'd got children.

It's only a question of boarding underneath it with something other than chipboard in most cases.

Almost as mad as not servicing a boiler for 12 years.

I thought you already had a working boiler

why would you pay him money to convert your system to a less reliable unvented one?

people are too easily swayed by bs.

that would seem logical! All you need is to move the tank (probably replacing it). Worst case you may need to add a pump as well, making the HW pumped.

NT