HEATING + HOT WATER - 4 OPTIONS. WHICH ONE IS CORRECT?

[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

 

[namsag]

Up grading the mains may not work as the pressure might not be there to start with. Various test first and can be very expensive to upgrade

If your boiler is newish why change it you could leave one hot outlet working off the combi pref the kitchen sink as its the one you use most often without a big demand on it.
Then connect cylinder with tank(s) in the loft for your bathrooms
Why have they suggest twin coil are you thinking of adding solar in future 300 is a big cylinder . reheat tines for modern cylinders are 20 mins a standard bath holds probably around 190 litres of mixed water
Pump on HW outlet would give you good delivery much the same as a megaflo would give

 

[sspaul121]

Hi

We are considering Solar power in the future hence the requirement of twin coil.

I have also been advised that as the pump maybe in constant use the lifetime of it is normally 3-4 years and cost approx 300 for a resonable one.

The other option I suppose is to install megalfo alongside existing WB 30cdi and also install an accumulator. Is this viable?

 

[Agile]

Namsag has explained what the best solution is but you have either not read it or not understood it.

Why would you want to run a pump 24/7 ?

Tony

 

[OwainDIYer]

Might you want to convert the loft in the future (i.e. remove all loft tanks)?

If not, then a conventional HW cylinder heated by the existing boiler.

If yes, then look at unvented HW cylinder, heated by the existing boiler. This could be supplied by a loft tank for now, with the option of upgrading the main (if necessary) and going unvented in the future. However if you can/will not go unvented this would be an unnecessary expense.

No point in chucking out perfectly good existing boiler.

 

[sspaul121]

No room for loft extension as roof space is only 4ft high. So probably no room for a HW cylinder.

The funny thing is the loft still contains the old plastic water tank so this could be utilised for the supplying the HW cylinder as you guys have suggested. Slight saving there.

The Combi boiler will be removed anyway and will be placed in the detached garage along with HW cylinder we choose. The area that's left will be used to create new side entrance to house.