Central Heating Pipe Diameter

[chameleon001]

Hi,

I have just had a plumber move some central heating pipes off a wall we will be removing. These were 22mm copper. He has replaced with new 15mm copper. These tee off the main 22mm pipe from upstairs and will therefore be supplying all the ground floor radiators (5 radiators).

Now I know I need to add up all the BTUs to figure out this out but is it OK to have my entire ground floor run off 15mm? So stupid not it question it at the timed obviously concerned re. the functionality of my CH come the winter. As most of the rads are disconnected due to refurb work I cannot fully test it.

I guess I don't have a leg to stand on in terms of getting it rectified if it needs it anyway.

Any thoughts?

Thanks,

Dan

 

[muggles]

Doesn't sound ideal. As a rule of thumb I don't usually run more than two radiators off 15mm, but will occasionally stretch to 3. As for whether you have any recourse, that depends on whether you've paid up or not!

 

[chameleon001]

Hi,

Not the news I wanted, yes I have paid up. Have contacted him but not holding out much hope.

Thanks

 

[Madrab]

As most of the rads are disconnected due to refurb work I cannot fully test it

What size are the 5 rads? If I was you, I'd be caveating that job with the plumber and not 'signing it off' until all the rads were in and the system tested, if they don't all warm up properly then he'd be back to fix it. As @muggles mentions, if the 5 rads were a reasonable size then it might struggle.

 

[Nige F]

What was the "plumber" thinking ? What logical reason prevented 22mm pipes

 

[Nozzle]

What is the rule of thumb for 15mm and 22mm pipe capacity? Does it matter if pipe is oversized making flow too slow?

Nozzle

 

[fixitflav]

What was the "plumber" thinking ? What logical reason prevented 22mm pipes

One eye on his bank balance would be my guess

 

[ReganAndCarter]

What is the rule of thumb for 15mm and 22mm pipe capacity? Does it matter if pipe is oversized making flow too slow?

Nozzle

A very rough rule of thumb is max 15,000 BTU for 15mm. This is a very rough approximation though, and could be affected by other factors. As above, max 2 sizeable rads or 3 smallish ones off of 15mm.

 

[chameleon001]

What is the rule of thumb for 15mm and 22mm pipe capacity? Does it matter if pipe is oversized making flow too slow?

Nozzle

A very rough rule of thumb is max 15,000 BTU for 15mm. This is a very rough approximation though, and could be affected by other factors. As above, max 2 sizeable rads or 3 smallish ones off of 15mm.

Hi,

No logical reason why he couldn’t have used 22mm, guess I have no other choice to go with it unless I get someone to rip it out and redo in 22mm.

Thanks for your help anyway.

Dan

 

[Terrywookfit]

Also depends on Load....length of run....dt...and velocity.

 

[chameleon001]

Yes obviously each system is different.

Would this be a possible work around...If things don’t run well on 15mm, add an additional drop down in 22mm to feed the majority of the ground floor rads, keeping this 15mm drop down for 1/2 rads? Quite easy to do as have suspended ground floor so can replumb easily?

I know ideally I’d get it redone in 22mm but obviously £££ as my Plumber thinks 15mm is fine.

Thanks,

Dan

Thanks,

Dan

 

[Terrywookfit]

What size are the rads...and how long is the run?

 

[ReganAndCarter]

Would this be a possible work around...If things don’t run well on 15mm, add an additional drop down in 22mm to feed the majority of the ground floor rads, keeping this 15mm drop down for 1/2 rads?

You may end up doing something like this, which would undoubtedly help. One thing I forgot to mention is getting heat to downstairs rads is always a little more difficult than upstairs rads. The reason is because heat rises and will favour the upstairs rads and trying to channel it downstairs to all rads in just 15mm is another factor against getting the heat downstairs.

 

[chameleon001]

Hi,

Total rad btu is 10,000 - 12,000

The run from tee off upstairs to furthest rad is about 10m, 2 pipe system so say 20m total, plus teeing off to each rad.

 

[FiremanT]

TBF, I have see many houses ran completely in 15mm, and working