Plumbing changes for extension

Dave121

Hi Folks,

I am getting an extension built onto our existing semi detached house and have been presented with a few different views from different plumbers. I know nothing about plumbing so need some advice. Unfortunately there's a long explanation before the question...

The house is being extended from 1200 sq ft to 1800 sq ft, increasing from a 3 bed standard semi with 1 ensuite to 5 bed semi with utility and 2 ensuites. Also, we want to move the boiler from the kitchen into the utility room.
We currently have a Ferroli combi boiler rated at 80k btu. The water pressure in the area is so low that the Fire Brigade have complained to the council that the pressure is too low for them to efficiently put out a house fire if so required.

The builder we are using is excellent and I have no complaints about him so far. He is having some trouble scheduling his existing plumber due to the plumber being so busy and the only other guy he knows is only willing to do the gas works but not regular plumbing work.

I have spoken to both builders contacts and they have suggested a simple move would suffice but one suggested that we install a cold water storage tank and a pump to increase pressure within the house.

This evening I have spoken to a plumber I know through work who seems to know his stuff and comes highly recommended also. He has suggested that the existing boiler is replaced with a condensing modulating boiler ?? with hot water storage tank and a pump. Something about having two hot feeds for the heating and two for hot water and it being a hot water priority system??. He reckons it will be so good that we can scrap our plans for a second electric shower and fit a mixer shower (which I would prefer).


My contact admits that the system he is proposing is much more initial expense but reckons it will be much more efficient long term.


Any views would be greatly appreciated?

Dave121

davidoco

Firstly if your incoming water pressure is poor the addition of extra components to satisfy the combi boiler requirements, while a solution, never really solves the problem in the long run. You just have one more pump to cause problems.

Combis are great when you have the pressure in front of them. Simple plumbing etc etc.

Condensing (modulating?) boiler is the way to go but if your current system is less than 6 years old it's a bit much throwing it out.

My favourite would be pressurised stainless steel tank stored hot water heated off whatever takes your fancy (even the combi - treat it as another zone).

The priority issue is not so important anymore because of excellent insulation on stored hot water tanks.

Dave121

Thanks davidoco,

The combi is only 3 years old so the plumber reckons he could get a buyer at about 300-400 Euro.
As we were moving the boiler anyway the cost of labour to do that subsidises the cost of the new boiler also. He reckons that the net cost of a new boiler over moving the existing one is only about 300 Euro (providing we get the old one sold). I think the additional expense is the tank, and a pump. He suggested a water-cooled pump costing about 450 Euro, but he says it would be the biz.

Would you be able to comment on the capacity of the Ferroli boiler being enough for a 1800 sq ft house?

D

davidoco

Dave121 wrote: »

Would you be able to comment on the capacity of the Ferroli boiler being enough for a 1800 sq ft house?

Not really. Each and every 1800 sq ft house could (will) have a completely different heat demand. Whats the model of suggested boiler and KW output and what have you at present? Most (all) Ferrolis condensors have an A rating so that's a good start. Your existing Combi is probably a D.

Dave121 wrote: »

I think the additional expense is the tank, and a pump. He suggested a water-cooled pump costing about 450 Euro.

Costs would be

New boiler ???
Move/and/or install new boiler flue kits and all
Cold water cistern with booster pump - water cooled is good as it is quiet.
Hot water storage cylinder (pressurised) at least €1200.

Fair enough no electric showers but you need to fix thermostatic mixers which can cost just as much. Very nice though having a peaceful shower with no pumps whizzing away nearby.

Dave121

Well I made the decision to go with the full upgrade! I reckoned that if I was ever going to do it, now would be the ideal opportunity and if I didn't and found out later that the existing boiler wasn't up to scratch I'd be kicking myself.

For those who might be interested the pricing was as follows (I'm sure I'm leaving out some of the smaller items though)
120k btu condensing boiler
Timer programmer
Pressurised hot water tank
Upgraded cold water cistern
Water cooled pump
All the necessary valves, flu etc.,
1 * 1200mm double rad
1 * 1200mm single rad
1 * 600mm single rad
1 * 600*1200mm towel rad
All pipework
Materials cost - 3470 Euro

Labour includes installing all the new gear and removing the old boiler - Labour costs - 3200 Euro

He will leave us with the old boiler until he finds a buyer which he reckons won't take too long.

I'll post back here when the job is complete to let you know how it went and whether it was worth it or whether I should have spent the money on beer

Thanks for you comments davidoco