New Boiler installation central heating ugrade

Hi All.

Long time reader of these forums (very useful) but now in need of some advice etc.

Just moved into 1950s 4 bed detached in Berkshire. One bathroom 2 adults 2 small children (2 years and 6 months). In need of general modernisation etc. Plan is to modernise/install new kitchen/Bathroom/Upgrade boiler & heating/water softener and then redecorate etc.

This is going to be our Long term house (not moving again) as it is on a big plot/good road/well built/plenty of future scope for extensions/loft conversion etc.

The long term plan is to add a 5th bedroom with ensuite in the loft and single storey extension on the back to enlarge kitchen etc. But at present I just need to modernise what is already there. (kids are too young at the moment that we don't need another bathroom)

So to get to point. I need to remove the old floor standing boiler from the Kitchen (Potterton Kingfisher 10-15 years old) and put a replacement in the integral garage which backs onto the kitchen so not far to move it.There are 9 radiators in the house including a towel radiator in the bathroom and a gas fire in the lounge and a gas cooker. The system is OLD.Gravity fed hot water cylinder/pumped central heating and I think it may also be a single loop (the radiators only have a valve on one side). Two tanks in the loft etc.

My preference is to convert to a fully pumped system boiler with a hot water cylinder rather than go the Combi route. But obviously with both of these I can get rid of the tanks in the loft (freeing it up for future conversion).

So what is the general opinion should I go Combi or not (assuming I have enough water pressure etc) . I prefer to have the back up of a cylinder with immersion etc and just not convinced by combis as it just seems so much to go wrong (or am I just living in the past?).
Been looking at the vailliant system boiler with Unistor cylinder or if I go Combi the Vailliant 937.

Also whichever I decide it needs to be future proof (addition of extra bedroom/ensuite/larger kitchen etc and upgraded bathroom and extra demand for water use etc as the kids grow up).

I also assume that you would recommend conversion to a 'proper' flow and return system for my rads if it is single loop. .

I have got 3 people coming around (all Corgi guys) and all either reccomended or friend.

Should I let them come up with recommendations to start with (as I am no expert but just have a hunch as to what I want/need) or should I tell them my preference. What would you do?

The cost is obviously part of it but more importantly I want to be certain I am getting what is correct considering the long term.

If any of you Corgi guys live near Maidenhead Berkshire maybe you can also come and give me a price/advise seeing as you read these forums I presume that you are good.

Thanks,

JON

prefer to have the back up of a cylinder

as you say the unistor or a megaflo system.

combi's are a waste of time flow rates etc ok for the small family with one bathroom.
no good if you like a powerful shower with multi jets, and ensuite.

yes hot water cylinder back up seems to make good sense to me. At least if boiler packs up etc I can still have hot water.

What is your opinion on the Vailiant fully integrated with the Unistor controls etc. Also can the unistor be fitted in the garage next to the new boiler. As this would free up the airing cupboard space that I could then maybe extend my bathroom into?

get the corgi's to check the cold mains pressure and flow rate, without either of these being good then an unvented is a waste of money. Also in an ideal world you need your incoming cold mains in 25mm pipe as the un-vented cylinders need a 22mm cold supply to them.

From the description of what you have a Vaillant 837 combi would give all you need as long as the water pressure and flow rates are good, for that extra bit of future proofness the 937 will be even better.

Both will give very powerful showers.

If you want to go down the un-vented route then make sure your installer is G3 rated. The Unistor is the better option and couple this with an Ecotec Plus 600 series boiler and VR65 control centre and VRT 360 programmable room stat and you will have about the bes system on the market.

Yes will get them to check. My preference is for unvented so I will need good pressure and flow. If these are not great would you suggest going the Combi route and suppose with the V937 that has the water storage also?

For the 937 to give its best you will need the same pressure and flow rates as for the un-vented and the chances are a lot larger gas pipe from your meter to the boiler than what you have now.

The main thing you will save is space from having no cylinder.

IF i don't have sufficent flow/pressure what are the options.

I presume:

A) dig up drive etc and put in larger water supply pipe from the meter. This would then give me the option to either go Unvented or Combi.(also put in larger gas pipe this should be easy as the meter is also in the garage)

B)Leave water supply as it is and just go the traditional route of open vent boiler/normal water cylinder/tanks in loft etc.

C) Is it not possible to increase the flow/pressure by some other means enabling me to go unvented with a system boiler?

THanks

JON

Larger supply pipe will increase flow but not pressure.

You could go to the expense of having an accumalator fitted if your flow and pressure are too low. Unfortunately I have no experience of thes so cannot advise on them.

Hopefully SimonD will be on later. His company has fitted loads so he can advise professionally.

Forget tanks in the loft. Look at the simpler combi route first and fit them in the garage. Buy a quality model.

High flow models are available:

Wall mounted:
Alpha CD 50
Glow Worm Extramax
Vaillant 937

Floor mounted:
Viessmann 333
Worcester Bosch 440 Highflow
Vokera
ACV HeatMaster
Atmos Multi
Gledhill Gulfstream
Glow Worm Ultramax
Ideal Istore
Potterton Powermax
..and so on...

Your mains must have enough pressure and flow. Test it. Fill a bucket and what is it in litres/min

* Fit a new larger bore mains water stoptap as these can restrict flow.
* A dedicated 22mm supply to the combi from the stoptap - no tee offs, except the cold to the showers which you take off just before the combi on the combi supply - any pressure variations around the combi will affect the shower too, to prevent serious pressure hot and cold pressure imbalances.
* All other cold supplies are teed of at the stop cock in their own dedicated line, which may be 15mm.

One approach is two combis

* can be side by side or stacked on the wall, say in the airing cupboard - taking up little space.
* One combi doing upstairs CH, one down (each with its own stat/programmer on the wall),
* One doing one bathroom, one the other. Divide and rule.
* Combine the outlets for baths to give 24 litres/min flowrate - the only outlet you need high flowrates.

Try the Atmos 12 litres/min Intercombi. Expensive but super reliable - no integral 3-way valve and the DHW works even if the pump fails.
http://www.tbsmerchants.co.uk/cgi-bin/build/detail/PA010010.html
Just under £800 each. So, £1,600 for two. Price up a quality RR boiler and a large megaflo and zone valves, stat, etc. A 250 litre Megaflo cylinder is over £1,100 and 300 litres over £1,200, then around £1,000 for a quality system boiler. The Atmos combi route is hard to beat on price. and no space taken up.

There is no need for a condensate pipe as the Atmos has a kit to squirt this out of the flue. This is more cost effective route than one boiler, zone valves, complex electrical controls and wiring doing the CH and an unvented cylinder. And you have CH and DHW backup if one is down. And you never run out of hot water and two people can have simultaneous showers and one not affect the other - for ever.

Now you can have upstairs off during the day saving money on bills - the system is naturally zoned by the combis, and showers at any time for as long as you want.

I personally would do the Atmos two combi route, after that a heat bank (thermal store cylinder)

Note: make sure on any mains pressure system that the showers mixer have integral pressure equalisation valves inside.

As Dave says, if you would like unvented but do not have enough water, an accumulator will usually work excellently (I say usually because we don't have a static pressure measurement for your house).

However, the accumulator/unvented option does take up a fair bit of space, in my case, a quarter of the utility room.

Thanks for all the advise Guys.

Alot to take in but some good knowledge for me. Corgi guys coming next week so lets see what they recommend!

Will keep you posted.

JON