Slow hot water to taps and excess old pipework

[awatson]

I am in the middle of renovating the bathroom (making it bigger, moving the shower and sink, putting a bath back where it used to be before someone fit an accessible walk-in shower) and I thought I would trace the pipes while boards are up to see if can resolve some of the issues we had been having of hot water taking an age to reach taps in the bathroom and kitchen at the same time.

The boiler was replaced with a modern combi at some point, which is in the garage, against the back wall of the house.

Whoever fit the boiler hooked it up to the existing pipework in the airing cupboard on the first floor, where it runs up to the loft, does a little loop, then comes back down again before branching off to appliances.

Pipes just run straight up, do a bit of a convoluted turn, and come back down again, all the old tanks were disconnected and I've removed them now (dead mouse included).

Would taking out the loop to the loft (probably ~5m of excess pipework, mix of 22mm and 15mm) give any real benefits in terms of getting hot water to the taps quicker? Or is the main issue more likely to be the route from the boiler to the airing cupboard?

The kitchen run is particularly long.The pipes go down through a partition wall to the ground floor, then run behind the units in the kitchen pretty much back to the garage. I'm not sure if it would be better to see if someone could do a more direct connection from the boiler.

The screenshot is my sketchy plan of the layout I've been using to plan things out, roughly to scale, with dotted lines for either unknown routes, or where I'm planning on braching off to install a new sink and shower (i've moved the bathroom wall). Included a photo of the airing cupboard as well...

 

[cross thread]

If you’re doing work I would re pipe and make the runs as short as possible

 

[cdbe]

I'm a big fan of 10mm plastic pipes for sinks and 15mm for showers run direct from heat source. The 10mm can be a bit noisy but virtually instant hot water at every draw off (we have an unvented cylinder) is fantastic.

 

[awatson]

If you’re doing work I would re pipe and make the runs as short as possible

I'm a big fan of 10mm plastic pipes for sinks and 15mm for showers run direct from heat source. The 10mm can be a bit noisy but virtually instant hot water at every draw off (we have an unvented cylinder) is fantastic.

As an idea it takes a couple of minutes to get hot water to the bathroom at the moment, longer in the kitchen. Instant sounds better but not sure I could achieve it . In an ideal world I'd probably repipe, but I don't have the time/the skills to do it myself where pipes aren't accessable, and I doubt I can afford to get someone in at the moment. Not sure how much it would cost though, could be surprised.

As a compromise without redoing everything, I'm thinking of getting rid of the loop to the loft, and switching the hot water where I can access it upstairs from 22mm to 15mm, branching off to 10mm for taps. Not sure if that is worth the effort or whether any gains will just be marginal since I'll still have the long run of 22mm from the boiler.

 

[Deleted member 294929]

I'm a big fan of 10mm plastic pipes for sinks and 15mm for showers run direct from heat source. The 10mm can be a bit noisy but virtually instant hot water at every draw off (we have an unvented cylinder) is fantastic.

I agree, I've a combi and run 10mm to all my hot outlets individually. I was sceptical about the bath but it works well.

15mm is the norm from a combi and 22mm mm is really too.much volume and will take an age to rid the cold water before getting heat to the outlets.


10mm is less volume so saves on water bills and maybe gas bills too.

Try complete runs from A-B with no fittings

 

[Deleted member 294929]

As an idea it takes a couple of minutes to get hot water to the bathroom at the moment, longer in the kitchen. Instant sounds better but not sure I could achieve it . In an ideal world I'd probably repipe, but I don't have the time/the skills to do it myself where pipes aren't accessable, and I doubt I can afford to get someone in at the moment. Not sure how much it would cost though, could be surprised.

As a compromise without redoing everything, I'm thinking of getting rid of the loop to the loft, and switching the hot water where I can access it upstairs from 22mm to 15mm, branching off to 10mm for taps. Not sure if that is worth the effort or whether any gains will just be marginal since I'll still have the long run of 22mm from the boiler.

It's taking so long to get hot water because you have to rid the cold water in the oversized 22mm pipe first. That's alot of wasted water.

You can buy 25 m of 10mm polypipe thst is so flexible. It's so much easier to run than 15mm

 

[Deleted member 294929]

Just a note on running 10mm poly or any sized poly, is that it's not to be used on secondary return pipe systems. There are exceptions to the rule, Butline being one manufacturer.