8mm to 15mm is it worth it?

[blasted]

I currently have an 8mm micro bore system. The boiler was changed a while back to an ideal condenser. The system is working well apart from the radiators in some rooms are single panel and not very efficient.

I’m considering a loft conversion and one of the factors of doing the loft will be to move the hot water cylinder, pump and some of the pipe work.

Now if I replace the boiler with a combi, I can get rid of the pump, cylinder, storage tank and header tank. This gives me plenty of room for a staircase.

But I also want to put a radiator up in the loft space and possibly another radiator in the kitchen extension (a considerable distance from any manifold).

Would it be worth changing the pipework to 15mm? I appreciate I may have to drop it down the odd wall and run it along some skirting but I can live with that if the system is efficient. I would also look to change a few radiators for some more powerful ones.

Another bonus of changing to a combi would be the saving. I live on my own and don’t need to heat a full tank of water every day.


Thanks

 

[muggles]

A complete re-pipe would be expensive and you can't just add 15mm pipe to an 8mm system. Unless you want to go down the route of having your entire house re-piped you'd be better off sticking with the 8mm, and extending the manifold if necessary.

What exactly are you expecting to save by changing to a combi? Because believe me, it's going to take you forever and a day to regain the cost of installing it against keeping what you've got and paying to heat your cylinder every day. Much better/cheaper to simply buy a smaller cylinder, that'll pay for itself much faster.

Having said that, if your current boiler isn't powerful enough to cope with the new rads, you'd be better off changing it, and in your circumstances a combi may well be ideal.

 

[blasted]

As it stands the boiler is fine.

The problem is when i come to do a loft conversion. At present the cylinder and pump are in an airing cupboard in the box room. The only logical place to put a staircase and maintain headroom with the least amount of disruption to the proposed floor above goes right though the middle of where the cylinder is, and its allready pretty small.

My thoughts were if everthing has to be moved, why not just get rid?

Then i thought about stepping upto 15mm pipe.

In the past when i have rads on and off to decorate i have never felt comfortable with the flimsy 8mm pipe. But its a case of weighing up the pros and cons.

Thanks

 

[muggles]

Well as everything's being moved I suppose you could go for a combi, as I said it's going to take ages to pay for itself, if it ever does, but as you're on your own it would be more efficient from a water-heating point of view. As you have a condensing boiler already you won't gain much in efficiency, however being a condensing boiler means it can still be fitted, so you might be able to flog it on eBay.

There's nothing particularly wrong with what you're suggesting, and from both a water-heating and space-saving point of view it's a good plan, but it'll cost you quite a bit for a full re-pipe if you want to move to 15mm, and I can't really see the point in doing this.

 

[Paul Barker]

Aslong as the microbore is copper if you cleaned the system you can probably get away with it.

As for a combi. I got a legitimate 3 year old 28kw Potterton band A combi off ebay for £145. But we still haven't had the heating on yet and the solar energy gives us all our hot water most days, but when it doesn't the backwards tmv gives the new combi a job and lovely piping hot water at 55 degrees come out of the tap as fast as
I need it to.