DIY Plumb details inside (with layout pic)

[jlaw]

Hi Everyone,

I'm going to replumb my bungalow myself as at the minute its an old system with cylinder and multiple tanks in the roof. It'll all be fed of a firebird 26kw oil combi boiler.

The property is suspended wooden floors and I can get into the crawlspace so all all piping will be run under the floor.

does my diagram below look ok?

I'm going to be using 15mm to bring in the mains and then teeing off in the garage to supply cold taps etc. and boiler.

The central heating pipework will all be 22mm and then 15mm of the main flow and return pipes to each radiator.

do I need to install drain valves or anything else anywhere or is my basic map pretty much ok?

does anyone have any hints or tips to make it easier or work better?

All advice is much appreciated.

Alternatively if anyone on here is located close to Exeter in Devon and in the trade please feel free to contact me as I might find I don't have the time to do it and I need to employ someone to do it for me!

 

[Terry lambert]

If your heat load is less than 10 kW ( or 11 kW - a 20% allowance for fittings) then it will not work any better than if you run 15 mm flow and return pipes.

Run 22mm to the first rad and then reduce to 15mm from there, it will save you money on materials and be easier to install. When balancing, aim for a 20 degree differential between flow and return

 

[Terry lambert]

Yes fit drain cocks on any drop feeds.

I also put at least two drain cocks in at convenient places where it's easy to run a hose to outside.

Under boiler ?
Rad near a door.

Or drill a hole to outside and run a pipe with a drain cock straight to outside
( sleeve the pipe)

Fit a mini expansion vessel on the cold main and if your in a hard water area, a decent scale reducer like a combi mate

 

[PotatoHead]

Go 22mm from the stop tap to where it splits for cold/boiler feed, (provided the incoming main is similar size or greater).

 

[jlaw]

Excellent advice guys!

I will take it all into consideration - although I'm not sure why I would need an expansion vessel?

If there are any other things I should be doing please let me know!

 

[Terry lambert]

Most manufactures ask for it in the instructions, to protect the boiler/ plastic hydro bloc, especially if you have a water meter, non return valve.

Often missed until there is an issue

 

[jlaw]

Most manufactures ask for it in the instructions, to protect the boiler/ plastic hydro bloc, especially if you have a water meter, non return valve.

Often missed until there is an issue

Ok, I just had a read about these and will install one too as we are on a water meter.

thanks for your help.