House renovation (5 bed 3 bath) what type of boiler? adding a pump too??

katepnlo · 21 May 2013 at 9:00AM

Hi,
At the moment we have a boiler, tank in the loft and tank in the airing cupboard.
We are renovating our house. 3 bathrooms (had one standard shower and 2 electrics) and the third bathroom has switched rooms, now about12ft towards the back of the house rather than in the centre. we will have 2 normal showers and only one elc shower.Adding a LARGE 2 person bath.

12 rads.

I do remember when we bought the house it was mentioned the boiler that was here wasn't really big enough. We have had to use one shower the last few months(8 people) and frequently run out of hot water.

Question is, what sort of boiler would be best for our house?
We were thinking of getting a pump also. New big bath fitted and new system shower went on yesterday and the hot water pressure is dire

I will be searching myself too, but I could do with an additional 10 pairs of hands to do all the work that needs doing this week

so I really would appreciate a shove in the right directions with any helpful information you can share.

THANK YOU!!!

diywhynot · 21 May 2013 at 9:11AM

Have you had anyone in to quote/advise on the optimum setup for your CH and DHW, perhaps before you had the new bath and shower installed?

katepnlo · 21 May 2013 at 9:22AM

That is by far the most logical thing I could have done. I hold my hands up. That is my stupid mistake of this renovation. Everything else has worked well in all other aspects.
Slapped wrists and major fail on my part accepted :P

katepnlo · 21 May 2013 at 9:51AM

Ok. Coffee before I start work. I am thinking a heat only boiler. Am I looking along the right lines?

We won't be converting the loft and the tank sits quite happily in an airing cupboard in a bed room. Boiler has a nice big cupboard already downstairs.

southcoastrgi · 21 May 2013 at 10:21AM

why do you need to change the boiler, what is the make & model ?

if you have the pressure & flow on the incoming cold water main you could change to an unvented cylinder (however these must be checked),

if you can't do as above you could replace the cylinder with a larger one & fit a pump, but this may also mean the roof tank needs to be increased in size or an extra one installed, as DIY said you really need to get someone in who knows what they are talking about to give you options.

BTW A COMBI IS NOT SUITABLE FOR YOU, so if anyone you get round suggests this show them the door.

katepnlo · 21 May 2013 at 10:39AM

I came to the conclusion we needed to change the boiler as we were told our boiler wasn't really man enough. With addition of a stupidly large bath and another shower that runs off the hot water. Then the hot water pressure issue since these two items were added yesterday.

My current boiler is Glow Worm Flexicom 24hx.

Cold water pressure is good. Just hot water pressure coming out of new bath is terrible (nice waterfall taps...wouldn't call it anywhere near a waterfall!)
The shower went on yesterday and it is pitiful.

That combined with 2 adults and 6 children (7-16) presumed more hot water the better.

I know I need to get someone round really. (All tradesmen left yesterday, I was hoping to not have any more strangers in :P) But I want to be armed with some knowledge about all this before I invite people in who will realise I don't have a clue about this.
Thank you

southcoastrgi · 21 May 2013 at 11:20AM

Ok firstly unless you have really really big rads whoever told you your boiler isn't "man enough" is an idiot, if you have 12 normal sized rads then the boiler is too big,

when working out a boiler size (although Mr T will pop up with his whole house calcs thing), i take the output of the rads, add 2 kw for the cylinder, then add 10%, you have a 24kw boiler which on the above calcs will give you just under 20kw for the heating, i would be surprised if you needed any more than 15kw.

the amount of hot water you need is down to the size of the cylinder not the boiler you have, larger cylinder = more available hot water, height between the top of the cylinder & the bottom of your roof tank determins the head of water, greater head = better hot water flow rate (depending on the pipe sizes being correct),

if you need more hot water increase the size of the cylinder, if you need better performance from the hot water either raise the height of the roof tank or fit a pump (although fitting a pump will mean you may run out of hot water alot quicker & therefore you may need to increase the size of the cylinder or roof tank or both),

you could go for an unvented cylinder however you need to check what i have already said with regard to that & saying cold water pressure "is good" is no indication, both flow & pressure must be checked & you need to hold the G3 cert to fit unvented so when/if you get someone round for this option make sure they have it.

katepnlo · 21 May 2013 at 1:00PM

Wonderful. Thank you

)))
I have two tanks in the loft.(is that standard??) One on top of each other. I think the tanks must be quite high.... They are on a frame and I can just see over and into the top one if i tip toe (5'7")

Rads..I think 3 are double panel quite wide ones.( I would measure but I am eating lunch) The other 9 are single panel. But all standard rads. Nothing out of the ordinary.

So I should be thinking pump and looking at my cylinder and tanks. Very helpful. Thank you

Any info really is appreciated. Thank you for taking the time to help

southcoastrgi · 21 May 2013 at 1:15PM

no probs hope you get it sorted & at least you are going in the right direction now without spending £2k+ only to find out that the hot water is the same & all you have is a nice new shiny boiler

katepnlo · 21 May 2013 at 1:16PM

The joys of Google... A calculator tells me for a 5 bed 3 bathroom house I should be getting a 300l cylinder. Sound right?

southcoastrgi · 21 May 2013 at 1:48PM

I would have thought a 60"x18" (most plumbers work in old money when it comes to cylinder sizes lol) 1500mm x 450mm would be ok for you, modern cylinders have a very fast recovery time compaired to older ones, & you won't be using water in the bath or shower @ it's stored temp of 60d as you will be mixing it with cold, you may get away with a 48x18 but really you need to speak to the guy that is spec it & tell him how much hot water you are likely to be using & how often, a smaller cylinder will cost less to heat up but will give you less water to use, but a bigger cylinder will cost more to heat up & if you really don't need all that amount then you will be wasting gas to have the extra hot water just sat there,

I'm not quite sure on all these calcs what the size of the house has to do with anything, you could own buck house but if you only have one bath/basin/sink then a 36x18 cylinder is big enough

House renovation (5 bed 3 bath) what type of boiler? adding a pump too??

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