Which Boiler Advice

[IMM]

Yep if it is actual. Duh!

Good boy.

Worse than good.

2.4 kids , etc, etc. Not Liz and her dysfunctional obnoxious kids and her 9 palaces paid for by the taxpayer.

It isn't

[Frank Erskine]

and add....?

[IMM]

drivel is drivel.

[AndyHingston]

We actually use a Gas Tumble dryer and have done for some time now.

Andy

Owa> "Grunff" wrote

-- AndyHingston

[AndyHingston]

Paul,

Many thanks for the detailed reply. I will look into these models. M main reason for steering away from the stored systems is that once th storage depletes you are "normally" down to a fairly low constan delivery.

Do you know of a good supplier for the Buderus boilers?

Regards

Andy

Paul Barker Wrote:

-- AndyHingston

[IMM]

The low constant delivery is about the same for an average combi. Normally the store delivers high flow for most of what you will need in an average house. The recovery rate of the store is a minutes. You can have bath after bath as long as you have a few minutes between. baths.

If you had an overlarge bath, the first 3/4 would be filled very fast and the last 1/4, slower, yet the overall filling time is still quite fast.

The Buderus, according to Paul is 13 litres/min, which is not startling, but will give you a v good shower and fill bath leisurely.

The Buderus is seamless in hot water deliver because it has a small water store and very fast ignition system. The combi lag is mainly due to system proving before ignition, which allows cold water to run through the heat exchanger without being heated.

[AndyHingston]

Andy,

Thanks for your advise. The Heat Banks are a new technology for me an reading up on the system it looks very good, however, I am concerne that it may be a little over complicated for our requirements.

As you confirmed the Baxi WM MaxFlo looks good on the face but has disapointing un stored flow rate and hence why I had started to loo into the Condensing models which seemed to provide a higher standar flow rate of about 16lt (same as the MaxFlo stored delivery), dependin on model of course.

As mentioned the Baxi 133HE Plus Condensing Combi Boiler with a Maximu DHW Flow Rate (Delta T @ 35º Max) - 16.0 l/min looks good and at £40 cheaper than the Worcester Greenstar 40HE Plus Condensing Combi Boiler sounds a great deal.

Do you have any experience of how much lag I will receive from thi type of boiler as opposed to a stored system, especially as I ha intended to locate the boiler on a gable wall in the loft and th kitchen is one end of the bungalow and the bathroom the other!

Thanks again for your advice.

Andy

Andy Hall Wrote:

[Andy Hall]

Not really. You buy the thing as a ready to go package - i.e. with all controls and bits already assembled on the cylinder. It takes mains cold water in, gives hot out and has two connections to the boiler as for a normal cylinder. The electrical controls for it are also included and integrated.

Take a look at

for some examples.

You are going to have two lots of lags.

If it's a combi with no form of hot water storage, then you have to wait for the heat exchanger to warm up. I'm not certain exactly how long that takes.

With either arrangement, you will have the delay through the pipes. This is worse with 22mm than 15mm because there is more water volume. You can calculate it from the flow rate and then work out the pipe lengths, treating them as a cylinder. (pi x r^2 x length) This can be quite a while.....

One way round it is to use 15mm for longer runs as long as you can get the flow rate you need.

I would think about locating the combi either in or near the kitchen if you are concerned about this issue. I presume you would care about how long it takes to get hot water there than in the bathroom perhaps? Then use the heating side of the combi to heat some form of storage positioned nearer the bathroom where you are probably more concerned about flow rate.

[IMM]

Some combi's have a heat exchanger pre-heat or an integral small storage vessel to reduce the lag to that of a normal cylinder with the same length of hot water draw-off.

You can install a secondary circulation pump on combi, to keep the draw-off pipe hot all the time.

Fit a secondary circulation loop back to the combi's inlet with a dedicated pump, or a normal CH bronze pump if more pressure is required to operate the combi's burner. Most modern combi's will operate at low pressures these days. Check valves must be used to prevent the pump pumping down the mains. This is similar to a secondary circulation loop on a heat bank. Before the combi, the inlet must be a length of 28mm, preferably two in parallel. being a part of the secondary circulation loop, this stores hot water that will also prevent a cold spot when the combi is going through the firing sequence. The draw-off/secondary loop must be well lagged

Have a pipe stat on the loop near the boiler to keep the draw-off temp to around 40C, so it will not be extracting heat from the combi continuously.

Oh my God! It is best to get a stored water combi if high flows are required.

[Andy Hall]

CH pumps are not normally bronze. Bronze ones are used for potable water applications like this.

Did you want something?

It's better to get anything but a combi if this is required.

[IMM]

uh?

continuously.

How would you know? Do don't know anything about heating.

[Capitol]

Andy Hall wrote: Archimedes was your tutor.

Think hard about justifying this statement! (tutored?)

Regards Capitol

[Andy Hall]

Said he who claims to design gas supply systems at 50% beyond the manufacturer's specification, cuts plastic pipe with a hacksaw when the manufacturer explicitly says not to do so, etc. etc. etc. .....

[IMM]

No within spec.

[Andy Hall]

Not the manufacturer's one, as you admitted yourself, but then you're not within the Manufacturer's spec. either are you? (Neither am I for that matter - although it's through choice :-) ).

[IMM]

< snip >

Stop going on about something you know nothing about. You are making yourself look a real big fool.

[IMM]

Just to add. On the combi secondary circulation loop you can have as many 15 litre electric storage heaters as you like (distributed storage), a common item which can be had for around £60 or so. Hot draw-off from the combi into the cold feed of the 15 litre heater, hot outlet of heater to cold feed of next (in series).

- Haeraters can be under sinks

- A couple on the back wall of the airing cupboard taking little space, and also is, in a loft, etc.

- Have the taps on the pipe on the hot outlet of the heaters.

- Have a pipes stats in parallel on the inlet to each (pipe stats are cheap)

- Instant response at the taps,

- As much storage as you want scattered around the house at convenient points.

If drawing off a bath all the hot water stored in each will end up in the bath a they are all in series (in line in the draw-off pipe.). So, one under the sink, one under basin, two in the back of airing cupboard, one in the ulitility room, etc. 5 of them gives 75 litres unvented, no tanks in loft, high pressure storage for around £300, which is DIYable. When water is drawn off the combi and the stored water is used instantly, all combined. When the 15 litre tanks are exhausted the pipe states keep the secondary circulation loop on, and the tanks are charged up again.

If the combi is down then turn on the electric supply to them all, giving backup.

[Andy Hall]

Getting uncomfortable for you, is it?

As they say - "Some men are discovered, others are found out".

[IMM]

You are the one looking a fool.

[Dave Plowman (News)]

But anyone with an ounce of sense, or who has lived with both a storage and instant system knows a combi can't compete with the storage system. Which is why some combis include a small storage system to try and overcome the deficiencies.

Now at least on this you're anything but an amateur. Pity about the rest.