Boiler move and pipe size rad replace and remove microbore

[Cabbyfan]

Hi everyone,

Currently renovating a 2 bed bungalow (which has an unused loft conversion also work in progress).

I need to move the existing boiler as part of the loft works (flu issues) and as the current pipework is ok but not as I would like it I want to make changes while I have the opportunity.

The 2 attached diagrams show the current and propsed layouts. As well as the new boiler position, there will be a new additonal radiator under a large bay window (north facing) and the radiator in the dining area will move to the adjacent wall (so the french doors can go in).

There will also be 2 smaller radiators in the hallway rather than one big one by the front door. This will give some heat in the hallway allowing heat to rise where the new stairs will go.

Main concern is all the radiators are fed on 8mm copper tails from 15mm runs dropper from a short run of 22 from the boiler. I also want to replace all the existing rads as they are all very old and rusty / damaged for the most part.

Would much appreciate feedback / recommendations. The bungalow has cavity wall insulation but the roof space has very little at present. When I complete the loft conversion it will be fully insulated sub floor and under the roof rafters.

Cheers !

Pipe layout exiisting

• Cabbyfan
• 30 May 2014
• 1

Pipe layout proposed

• Cabbyfan
• 30 May 2014
• 1

Rad capacity calcs

• Cabbyfan
• 30 May 2014
• 1

Some of the existing pipework ! Not done by me !

Dodgy pipework

• Cabbyfan
• 30 May 2014
• 1

Untitled

• Cabbyfan
• 30 May 2014
• 1

 

[Dan Robinson]

Personally I would bring the 22mm down past the little hall rad.

 

[Cabbyfan]

Personally I would bring the 22mm down past the little hall rad.

Cheers Dan. You mean the one on the left just by the front door I take it ? Reading up on this, there seems to be a rule of thumb of 4 Kw or max 3 rads from a 15mm feed....

 

[Dan Robinson]

Pretty much.

 

[D_Hailsham]

You may not be able to move the boiler! Depends on what it is and availability of flues.

Use Whole House Boiler Size Calculator to find out what size boiler is actually required and compare to the total for your rads.

 

[Cabbyfan]

You may not be able to move the boiler! Depends on what it is and availability of flues.

Use Whole House Boiler Size Calculator to find out what size boiler is actually required and compare to the total for your rads.

Boiler is a rebadged Worcester, British Gas 532i so I'm not expecting difficulties in getting flue parts. As for boiler capacity, current bungalow minus what I will need for the loft conversion worked out at about 9Kw from memory but thanks for the info I will have a look.

 

[Agile]

Although quite modern that boiler is rather overpowered for your property!

One of the very few Worcs boilers which is easy to work on!

Tony

 

[Cabbyfan]

Hi Tony, thanks for the reply.

Indeed it is, but it is a good boiler and it was in the bungalow when I bought it so would me crazy to get rid. There will be 3 extra rads plus a second shower upstairs when all the work is done so my assumption is the extra capacity will be of use as well.

My main concern is getting the pipe work and rad sizing correct.

 

[D_Hailsham]

My main concern is getting the pipe work and rad sizing correct.

You need to take the three additional rads into account when sizing the pipe work.

Do you know where they will be fed from and their sizes?

The hall and the living room both show two rads, but only one is listed. Presumably that's the total for each room. Is the total split 50/50 between the two rads?

 

[Cabbyfan]

Plan for the loft conversion was to tap off the 22mm with 15 near to the boiler and go straight into the loft space feeding a rad for the master bedroom of no more than 1500w plus towel radiator in bathroom and possibly a small one for the landing area. It's not a big loft.

In the hall and lounge yes I am considering fitting 2 rads and not 1. The lounge is north facing and has a very large bay window with no radiator near. There is 460mm of space under the window so I'm thinking of fitting a 300 x 1400 rad under it and having a 2nd radiator in the current location unless the opposite wall is better.

 

[Plumber90]

Will you be doing the work yourself or getting a plumber in, it would be easier to give better advice looking at the job in person. Put your location up on here and someone may be able to help you.

 

[Cabbyfan]

Hi plumber90,

Doing it all myself apart from the boiler flue install, gas and commission. I have a mate who is gas registered. Havnt really had chance to go through the design with him yet, just the boiler new location.

 

[Cabbyfan]

Just wondering as well, size of rads. Is it better to have a single panel rad the width of the window it is positioned under for example or a physically smaller double panel rad that doesn't cover all of the window width ?

 

[Agile]

Some here will disagree because its quicker and easier to fit small doubles.

But I always use wide single panel rads.

These look better under wiondows.

They spread the heat more evenly.

They dont jut out so far into the room!

They are slightly cheaper per kW.

Tony

 

[Cabbyfan]

Cheers Agile. Kind of my thinking, smaller width rads look odd under windows and I'm sure don't perform quite as well.

I'm about to start running in new pipe work and will also need to order rads soon too but it's a decision to not only get output etc correct but they also have to look right in all the rooms.

As a rough calc I can replace all my rads plus 2 extras plus all new copper for about 800 quid inc vat based on stelrad kit.