Boiler/Heating advice

[MountainMutant74]

Afternoon PH

I'm currently having my house extended from a 3 bed, 1 bathroom to a 5 bed, 3 bathroom house.

Current boiler is a Worcester Bosch Junior28i. This used to struggle if someone was having a shower and a tap was turned on else where.

For the new build I was thinking of a Megaflow type system to try and maintain pressure.

We will be adding underfloor heating in a large open plan downstairs area plus 5 more rads and 2 more showers in the house. One of the showers is in a loft room.

My builder is suggesting I fit a larger pipe from the mains (removing the old lead pipe) and that then a more powerful boiler would be sufficient. Think a Worcester Bosch 440 (or similar) was mentioned.

Any plumbers in the house that can advise if that will be ok? Will a combi be up to the job or should I stick with the Megaflow idea? The plus of no megaflow is space in the utility room but the main thing is having good pressure with no drop if two showers were running at the same time.

Thanks in advance

MM

[Alucidnation]

What not ask the plumber on site, considering he can see it all first hand?

[MountainMutant74]

Plumber is not on site yet. Not at that stage yet.

Just feel my builder is trying to make me change what I had originally thought was the best thing. Great if that is going to be ok but would like a bit of expert advice.

[jagnet]

Combi boiler on a 3 bathroom house?! Go with an unvented cylinder or thermal store.

[Toltec]

We have a storage combi for our 1 bath + 1 shower room house, it works quite well as the internal tank delivers quick and pretty constant hot water, using a shower and running the bath does not work well though due to the limited mains pressure. On the new 5 bed 4 bathroom we are going to build not only will it have a pressurised hot water tank I intend to have a recirc system so the bathrooms at the top of the house will not need to run the taps for ages to get hot water through.

[Dave_ST220]

jagnet said:

Combi boiler on a 3 bathroom house?! Go with an unvented cylinder or thermal store.

+1

3 bathrooms you want unvented cylinder IMO.

[scottdm3]

I doubt the lead main will be man enough for an unvented cylinder

[MountainMutant74]

I think that's why they want to fit a larger pipe from the meter in the street.

I have seen the megaflow tanks in garages at properties in the same rd so must be ok

[tonycane]

you need to get your cold water main flow rate and working pressure measured first

[Eddieslofart]

Just done exactly the same configuration, all off a Rayburn with a whole house pump on vented gravity system.