Central Heating Systems

Why would you want to?

We got rid of our cylinder twenty odd years ago and wouldn't go back - unless we go to solar water heating.

Instant, constant hot water is a joy compared with that from a storage tank.

Mary

Perhaps the family likes baths?

You get constant hot water from a decent storage tank - a fast recovery one - with the added bonus of high flow to fill a bath quickly. In the average house, it's very unlikely a combi can match the flow rate of a storage system.

.......oh he is at it again.....more inane ramblings...he says....

You don't. The cylinder will run of of hot water, quick recovery one or not. He should stick to DIYing cabers.

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I think its also cheaper! as you heat what you use!

Andy

Our resident clown, just back from the pub, postulates thus...

Now anyone claiming to be an expert would want to know the size of the storage cylinder, the input to it and the demand on it.

Not so our resident 'one solution suits all' village idiot.

Nope. Bogus argument. A modern, properly insulated cylinder has minimal heat loss.

I agree, the only heat loss is from the pipes.

We have a mini instant hot water system in one of our caravans.

Mary

Hi,

How many W/hr does it take to keep a cylinder like that hot?

cheers, Pete.

In article , snipped-for-privacy@ikonami.com writes

Big mistake saying that, then you just get self serving opinions about why you would or would not want to do such a stupid thing ;-)

The name for the boiler you have is a combi and, should you chose, I think it likely that you could modify your system to stored hot water without replacing the boiler; it is after all a very expensive component. To do this you would add an extra zone to your heating circuit that could be enabled to come on separately and this would feed the heating coil of an indirect heated hot water cylinder. For lowest cost the cylinder could be fed with cold water from a tank in the loft or elsewhere.

This is of course a simplistic description, just to suggest it can be done, you would need valves, controls and thermostats to complete the picture.

I am thinking that the hot water output from the combi could be capped and no longer used but to be certain that this would not upset the operation of the boiler I think you would need to check with the manufacturer.

Estimated cost: Cylinder £120 Valves £70 Controls & pipework £50 Labour (1day) £200 Total: £440

There's no reason why you shouldn't alter the hot water pipe work so the combi still feeds the kitchen tap. The flow rate for that is likely to be adequate.

It's filling a bath - or providing a high flow shower - that lets down most small combis.

Keep it for the shower, where mains pressure is worth having

You could describe the storage systems as 'you use what you heated'. As always with these type of questions there are compromises, trade-offs etc. between the different approaches. Usage patterns can alter the choice a lot.

I reckon that the energy 'loss' of a _modern_ storage system is probably around £25/year. However for 1/2 of the year that £25 is not really lost and in many circumstances it is useful in summer. On the other hand, hot standby combis might get through £?? extra gas in a year.

Yet again non-hot-standby combis might cause your water bill to go up by £?? /year, or not depending on the tariff.

Indeed. We have such an irregular pattern of being at home that a storage system would be very unsuitable. If someone has the same pattern of life and usge (= boring!) a VERY EFFICIENT storage system could be satisfactory.

For us the instant/constant hot water system is a joy.

Mary

combi. I don't understand the people who want more. Only the other da a guy I fitted a huge unvented systen for, including new 25mm wate supply, (that shower would hose you out of the bathroom) now he' complaining how much water he uses every time he uses the shower.

This shows there is a rediculous point beyond which sensible peopl should not tread. The search for better showers is a bit like the hif bug, we spend a lot more money for a little gain

-- Paul Barker

Very few indeed. If you look up the U value of the insulation, the surface area and the temperature difference, you can calculate it.

In article , Paul Barker writes

You're starting to sound like IMM, stating an opinion and then trundling out a "just the other day" story to support it

Some people are satisfied with mediocre performance, some are not, folk that want top end stuff probably have trouble understanding how you could be satisfied with anything less

Just a thought...

Would be interested to know how much gas is used to keep the cylinder hot, should be easy to measure over a day or two when out by switching the CH off and leaving the DHW to idle.

I'd expect the loss though the cylinder insulation is fairly minimal, a few watts at most.

cheers, Pete.

In article , Pete C writes

At the risk of adding yet another post that has nothing to do with the OPs original question, my cylinder has it on the label:

Range, Grade 1, Double Lagged, Part L compliant

Be aware that this is a larger than average cylinder and that the max loss will prob be specified for a high hot water temp and a low ambient.

Some are happy with a 7.5 kW electric. That's up to them.

I assume you mean 22mm?

Perhaps you should point out to your pal that it doesn't *have* to be used on full. And in what way is he complaining about how much water it's using? I've got exactly that - an Aqualisa fed from 22m. With perhaps 12 ft of head. And it's just great. It washes you clean.

In the case of esoteric Hi-Fi it can be difficult to measure the differences which therefore become subjective. The difference between having a shower that gives you both the flow and temperature you want - regardless of the temperature outside and therefore that of the water it has to heat is clearly measurable and worth it.