Best boiler - Condensing (not combi) - unvented......some questions...?

[Simon Hawthorne]

Hi

I have posted a few question here about different things and I have some more..(thanks again in advance)...

Ok, looks like I am going to change the boiler in the house for a condensing type - not a combi - probably an 'unvented' system. This has come from several recommendations as 'the best solution' - and I'll be totally honest, I don't really understand how it all works!

I currently have a boiler that has two seperate rad circuits (two outputs from the boiler) - each goes into a valve that is attached to a room stat - I have one upstairs and one downstairs.

All my rads have 'yorkshire' style connections. I want to change all the upstairs rads to have TRVs on them - so that when I convert the loft (a few years away yet - and I'll want to fit a mains powered shower in the loft), I can fit the same up there and be sure of a warm room.

Downstairs I will want to add four rads to - which will heat a room in the barn attached to the house. I am considering ditching the yorkshire valves and fitting TRVs on all - so that the same circuit can be used for the barn - which will also have TRVs - that way the room stat is bypassed - else it would keep switiching the circuit off while for example, the barn is still not up to temperature.

Anyway, I think this will work but can I ask a couple of questions....

1 I'm sure someone suggested it before - to remove the yorkshire valves - is it simply a case of taking the valve off, revoming the long tube that runs part way along the bottom of the rad, extneding one of the water pipes to it attaches at the other end, and fitting a TRV - or do I need new rads?

2 Just what is the best boiler? I'm not too fussed about £500 here or there - but I am not planning to move and my gas bills (mainly heating) run to approx £70 per month (averaged out over 12 months). I want an economical solution.....

I just can't seem to find any plumbers/gas fitters that are experienced enough to recommend a solution - you lot have been more help! I want to be able to decide for myself and then just task a plumber with doing the job - with all the choices made...

Thanks again...

Simon

[Simon Hawthorne]

Sorry to reply to my own post - I should add that I have not, as of yet done the calculations to determine just what size boiler I need - but I will......!

[Andy Hall]

Sounds OK so far. Certainly going for an unvented heating circuit gets you out of any issues with radiators in the loft

They should be OK, assuming that a) they are not corroded, and b) that at the end where the valve is now you can remove the fitting to leave a female threaded hole and c) that at the opposite end there is a plug which you can remove and also leave a threaded hole. You would then screw a lockshield valve in at one end and a TRV at the other. The microbore tube can be extended up and behind the radiator to conceal it. If you can't see a way to fit the valves because they are special radiators then you would need new ones.

Given all of this, if you are not going to move then you can take a long term view and go for a good quality boiler. In the area of condensing boilers, all of the good quality ones modulate their heat output, so as long as you have enough output to meet the needs of the building, then sizing is not hugely critical as long as you don't go mad.

I replaced my old Glow Worm boiler a year and a bit ago with a German made MAN Micromat

is an excellent product, very solidly built, anything in contact with condensate is stainless steel, modulates down to 3kW, models with max outputs of 16kW to 76kW, outside temperature weather compensation, etc.

I also looked at Keston Celsius 25 (25kW max), Worcester Bosch and Vaillant. All of these are good products.

.andy

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[IMM]

Two zones. Good Replace both with thermostat programmers, such as the Honeywell CM67.

Use a heat bank Google uk.d-i-y on Pandora.

The current Glow Worms are good and well priced.

go to condensing boilers. They are approx 104,000 BTU/hr and modulate right down. Quick recovery for a heat bank and a one size fits all. You will save approx 30-40% in bills. What size is the existing boiler?

[Andy Hall]

40% is probably optimistic, but 30% is certainly possible.

The 30SXi is a 30kW boiler. This is a large property and heating is being extended to other areas so more may be required.

.andy

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[IMM]

That's why I asked for the existing boiler size. If the property is being renovated then extra insulation should be fitted, which will reduce the heating load, which may mean the Glow Worms will be adequate.

[Dave Plowman]

If you don't know the size/type of the existing boiler, how can you know how much the bills will be reduced?

Pity the trades description acts don't apply hear...

[Simon Hawthorne]

Andy & co.....

Thanks for your replies so far....

Slightly off topic but you may be able to help. I am planning a new water main into the upstairs of the barn - I need to bring a new feed into the house anyway as my current main is 160'+ and in a lead pipe.. One thing I didn't really want to do was bring new electric and gas feeds in - instead I'd like to fit a meter between the properties so I can see exactly how much gas and leccy the office (first floor in barn) has used.

Are there such devices out there, and if so, where....?

Thanks again

Si

[Christian McArdle]

The barn has a sufficiently different usage profile and heat response profile that if doing it myself, I would DEFINTELY put it on its own circuit with a programmable thermostat. I would not share with any house circuit. You can have as many zones as you like.

Christian.

[Christian McArdle]

Electricity meters are easy enough to come by. Not sure about gas, but I suspect so. You can also get CH meters. These measure the flow rate and temperature difference of the flow and return pipes and calculate the kWh used for heating.

Christian.

[Andy Hall]

You can get gas meters from BES and electricity ones from TLC

.andy

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[Andy Hall]

Hmm. Do you know who has them?

.andy

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[Christian McArdle]

I can't remember where I saw it. Definitely in an online catalogue along the lines of BES, but possibly not actually BES. It was marketed for small blocks of flats and maisonettes to allow a central boiler with metered heating for the individual flats. I can't think of what they would be called to do a decent web search.

Christian.

[IMM]

You can have a main meter and your own sub meters fitted for separate properties.

How many baths, showers etc? Any idea of heat loss yet? I advise to heavily insulate the barn.

[IMM]

Called thermal meters which are not cheap. If there are two properties, it is best to have separate services, heating system, power, etc and meters. It makes it easier to sell in the future and easier on billing.

[IMM]

Thermal meters

[Simon Hawthorne]

Thanks Christian - I think that was my worry. Any houses I've lived in have had 1 CH circuit - and this one has 2. Is it a case of fitting valves into the circuits to divide them up?

[Simon Hawthorne]

I'd considered that but I am not going to sell it. Worst case is it will become a granny flat for myparents/in-laws one day. I am going to keep the ground floor...

I like the idea of these thermal meteres though - I wonder how accurate they are......?

S.

[Christian McArdle]

So far, my house has 3 zones. Tomorrow it will have another. In five years, I expect it to have up to 6. All heating zones have programmable thermostats. (Nice looking low profile Sunvic ones).

(Existing)

1. Downstairs CH radiators
2. Upstairs CH radiators
3. Heat bank (domestic hot water only) (Imminent)
4. Kitchen fan convector (Future)
5. Conservatory fan convector
6. Loft conversion CH radiators.

The locations of the valves do not have to be in the same place. The boiler and the heat bank are in the loft. The hot water zone valve (3) is there and the loft conversion zone (6) would follow. Unzoned trunk pipe goes down two floors into the understairs cupboard where the radiator zone valves are to be found (1+2). There is also an automatic bypass fitted here. The unzoned trunk then continues into the kitchen, round the back of the fireplace and under the units where kitchen zone valve (4) is already to be found, disconnected. Valve (5) will probably join it in the not too distant future, with the final leg in 15mm to the conservatory convector. The entire trunk line is run in 22mm. Each circuit drops to 15mm straight after the zone valve (except heat bank, which has a 22mm rapid recovery coil).

Christian.

[John]

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