What is the correct solution for hot water + heating?

[sspaul121]

Hi

Currently planning to renovate family home.

The current set up is 14 rads run off a WB combi Greenstar 30CDi. Mains Flow rate is 15 litres per min, which falls to 9 litres per min upon two taps being run. Mains pressure is approx 1 bar. Heating requirement for house is 18kw (I think)

The issue is that 2 family bathrooms will become 2 ensuites and 1 family bathroom. My family consists of 3 year old daughter and new baby in March; not forgetting my wife

Basically I have been advised that the boiler above does not have the capacity for future hot water requirements.

The confusing part is that 4 different plumbers have advised 4 different solutions.

1. Upgrade mains if required to 28mm to improve flow rate and pressure. Then replace existing boiler with WB 440cdi.

2. Upgrade mains if required to 28mm to improve flow rate and pressure. Use existing boiler alongside a Megaflo tank.

3. Upgrade mains if required to 28mm to improve flow rate and pressure. Use a conventional boiler alongside a Megaflo tank.

4. British Gas - Do not upgrade Mains as costly and may not work. Use a Water tank in loft connected to conventional boiler (B.Gas 330+ High Efficiency boiler), conventional vented cylinder (Range 300ltr twin coil) that feeds all hot water via external Pump.

Who is right?

Any thoughts suggestions would REALLY be appreciated.

Thanks,
Paul

 

[mfgs]

Id keep the existing boiler and just maybe use the instantaneous hot water for the kitchen or not at all. Then upgrade the mains and fit an unvented (megaflo) if you can get the flow rate and pressure required, that would be your best set up in my eyes. Seems silly replacing the boiler as it cant be more than about 4 or 5 years old.

 

[oldplumber]

leave boiler in situ and connect in an cyl heated via the flow/return from the central heating on boiler. you can upgrade mains in to allow you to use an unvented cyl or install a tank in roofspace for a vented cyl using current mains. then you can continue to use combi to supply kitchen hw and run bathrooms hw from cyl. new programmer needed along with motorised valves to control heating/hw system from cyl. Saves cost of new boiler, a 440cdi is still a combi I presume and wont work for 3 bathrooms unless one is operating an electric shower. what ever BG suggest will be very expensive!

 

[oldplumber]

theres 2 answer in agreement straight off

 

[dontknowitall]

I'm quite old fashioned and don't like combi boilers. Just about all of my "breakdown" call outs are for combis. Regular boilers (oil) seem to be much more reliable.

I also like the idea of stored water. If there's a mains problem there's no way you can get water apart from the local stand pipe. I much prefer a cold water cistern and a hot water cylinder. If the boiler breaks down there's an immersion heater in the hot water cylinder which gives an alternative source for heating water. There's also much less to go wrong with these.

I suppose it's a matter of choice in the end but for me storing water in the way we have done for yonks seems a really sensible system. Not as groovy as these modern megaflows and combis though!

 

[sspaul121]

Agreed.

Boiler is only 2 yaers old and a aprt of the refurbishment will be moved into the garage.

I think I may get the Mains upgraded first and see what flow rate we get, as I understand the minimum for a Megaflo is 25 litres per min. Else there is no point considering this.

Worse case scenario I will go with BG solution but get non BG installer to do the work to save on $$$$.

 

[sspaul121]

My original Point 4 above is incorrect.

BG suggested a new conventional boiler for heating and this would also feed the vented HW immersion cylinder. The 300 litre HW cylinder would supply all HW via a pump to improve the pressure.