Boiler cost comparisons

[Bob]

But doesn't that just mean the taps can cope with high pressure, rather than require it?

Bob

[IMM]

You don't put high pressure taps on a low pressure system. You will know it when you do.

[Christian McArdle]

Do you mean that your cylinder is heated from the boiler anyway, and that you use the immersion as well to get that little bit of extra temperature to fill the bath before it goes cold?

If so, the problem is that your cylinder is simply undersized for your purpose and should be replaced by a bigger model. If replacing and your mains pressure and flow is good, you may want to consider replacing with a heat bank or unvented cylinder, which will fill baths in no time at all and provide a superlative shower.

Christian.

[Christian McArdle]

I meant that the salesman should stick to selling baths and not give ridiculous advice about plumbing systems that he doesn't understand. The idea that the location of the taps makes any difference (although the actual design of the specific tap might, regardless of location), or that poor filling performance would be improved by getting a crappy instantaneous combi is laughable.

Christian.

[Christian McArdle]

I can assure you that if the taps with the largest commision on that he wants to sell you aren't capable of low pressure operation, then you can buy some from a retailer with a larger range.

Although there are indeed high pressure taps with thin passages suitable only for mains pressure, there is no relationship between the manner of the tap's attachment to bath or wall and this design "feature". The Victorians used wall attached taps and they certainly didn't have combi boilers.

Christian.

[Andy Hall]

OK. Basically what he is saying is that the taps are of a design that is intended to run on mains pressure (hot and cold) rather than from a roof tank arrangement. The path for the water through the tap is smaller in those intended for mains use.

This is quite a typical scenario for taps orginating from countries in continental Europe - often Italy, Spain, Denmark.

He was only aware of, or has been told that a combi boiler is needed to achieve a reasonable flow rate through this type of tap.

In fact, there are at least two other mains pressure HW solutions, including having a pressurised cylinder or a heatbank. Alternatively, you could use a shower pump with a roof tank based system to increase the pressure and flow for both the bath and shower.

OK. Is that because the boiler on its own heats the water too slowly or not to a high enough temperature or some other reason?

Ah... that's new information.

Does your wife's love of baths mean that she is like to want a good flow rate on the shower, e.g. for washing hair etc.? If so, and you are thinking about a combi, then look very carefully at performance. An 11lpm model would produce enough water in the winter to run a small shower head with fine jets but not particularly good flow. If she would like good flow, then you need something producing a good 15lpm. Is this bath/shower likely to be the only use of HW simultaneously in the house, or do you have a second bathroom or other substantial use of water? If so, and simultaneous use is needed, then a larger combi would be needed and may be marginal.

One of the stored solutions (cylinder or heatbank) would be a better choice then.

As far as baths are concerned, capacities do vary. You can roughly estimate volume from the dimensions of the bath and assuming a flat, square bottom - this would slightly over-estimate the need. Some of the shower baths have narrower sections where your legs go than a standard bath, so it really depends. If you can get a scale diagram of the bath, you can estimate the area on graph paper.

Then the crucial question is how deep does she like the water to be? I am pretty sure I know the answer to that question. Don't forget to factor Archimedes into the equation, but of course be diplomatic with your wife about that :-)

If you work on the premise that a simple combi, without any form of storage will produce its specified rate of bath temperature hot water in the winter, then that will give you the worst case time for filling the bath.

.andy

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[Michael Chare]

After posting I thought that a high pressure tap would likely use a smaller pipe that might make it easier to recess in the wall.

Another design option is to choose a bath with a horizontal elbow high ledge which is wide enough to take a tap. The water can come from a separate spout at the end of the batch with or without a shower attachment.

(I did that once)

Michael Chare

[Andy Hall]

Sure they did......

.andy

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[Christian McArdle]

IMM's house, though.

Christian.

[John Orrett]

The immersion heater is stand alone, and is put on say an hour before we need the bath. I normally turn up the boiler, and turn down the central heating to give some extra hot water

Mains pressure flow is excellent; however storage space for a bigger cylinder is not really an option. As stated in a previous thread, I have a plumber arriving tonight to inspect the system and make some recommendations. Thanks for your help, Regards John

[Christian McArdle]

I'm still not sure what sort of system you have. Presumably you have a cylinder with an immersion heater in it. Is the boiler plumbed into this at all? What do you mean by "turn up the boiler"?

Christian.

[Andy Hall]

It counts, because it heats the house as well (if you leave the doors open.

A win-win situation.

.andy

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[John Orrett]

Not actually sure where the taps originate from Andy, they were just part of the showroom layout for that particular suite (whose name escapes me anyway).

At present we need both the immersion and the boiler to give us a decent bathful of hot water.

Basically because the immersion tank itself does not give enough hot water due to its volume. The boiler is the 'top up'

No, the shower is for me!

Just the one bathroom. If we need a top up of water then as said previously, I turn the central heating down for an hour so the boiler has enough hot water to finish off the bath.

Duly noted :-). But yes, on the full side.

Many thanks again Andy for your help. Cheers John

[John Orrett]

That's right Christian.

Is the boiler plumbed into this at all? No, it's purely heated by the electric supply

What do you mean by "turn up the boiler"? We have a glowworm Ultimate 50 BF boiler that is used with a Potterton timer. The boiler is on constantly, albeit at a lowish setting. There is a Honeywell thermostat in the house. If I turn up the thermostat to say 20 degrees, then the boiler kicks in and provides the central heating. If the house is warm enough, then the boiler ticks over . If I turn the boiler up full, and turn the thermostat right down, that gives us the extra top up when using the hot water. Hope this makes sense. Thanks again for your help, John

[John Orrett]

That could make sense, using a smaller bore to reduce channelling.

One variety of 'shower bath' did indeed have enough room to take a set of taps mounted along the length. My wife, of course, wanted then in the wall :-). The standard fitting would be too simple. Cheers John

[Christian McArdle]

You amateurs no nothing about this.

If you embed it in the wall and fill it with sand, you'll gain all the advantages of increased thermal mass, so according to Tony Blair, you don't actually need heating at all.

Christian.

[Christian McArdle]

If there is no connection between your hot water system and your central heating system, why would the boiler have any effect whatsoever on your hot water?

Christian.

[Mark Begbie]

To address only the cost issue, it is well worth looking at

if you are thinking of a condensing boiler. This is an EU subsidised and manufacturer sponsored price reduction scheme that can be a fair bit cheaper than getting the same boiler elsewhere. When comparing their prices remember they INCLUDE a jig and flue, which would normally cost you another couple of hundred for the pair.

All the best,

Mark

There has been a bit of discussion about this scheme on UK diy already, regarding who can get these boilers, so to head that off at the pass I append the following.

I am NOT CORGI registered.

I requested their boiler pack, which includes the application form.

They sent it and it arrived in 48 hours.

I phoned them to say I am not CORGI registered, but was going to install the boiler myself, was that a problem? They said it was NOT A PROBLEM.

I returned the form with myself as the installer.

They sent me the coupon.

The boiler is now sitting in my kitchen.

[IMM]

recommendations

When I rang them that is what they said to me.

[John Rumm]

Did I mention flow rate? Did I not indicate thet they are a depricated solution? Is there anything wrong about the statement above? No Thought not!

As the finest example we have of such, you should indeed know.

(Clue for the clueless, appending an abbreviation after a phrase in brackets defines said abbreviation for the remainder of the "document" in question)

If you believe the advice to be wrong, then highlight the areas you believe to be wrong and explain why.

A working solution at a fraction of the price of that offered by a con merchant such as yourself:

Customer "I would like a set of taps that fix to the wall not the bath..."

IMM "Right you need two WB Js, and a complete re-plumb, that will be two grand please, oh and the taps will be extra"