22mm copper pipe of 28mm copper pipe, what shall I run?

[Moeen123]

Hi all. I'm new to this forum. Please go easy on me

I'm currently renovating my house and my house currently runs from old lead pipes then soldered in to 15mm copper pipe.

I want to replace the whole piping in the house from to bottom.

My question is shall I run 22mm copper pipe then reduce it down to 15mm?

Or the other options is shall I go bigger in volume. Because I have seen a 28mm copper pipes in Screwfix and Toolstation. Will this increase the pressure or volume of the water flow?

I have a 4 bedroom house. I hope this information helps.

 

[Scott_D]

Heating, hot or cold?
Have you tested your flow and pressure?

 

[Moeen123]

Hi.
Thanks for replying to me.

The pressure varies when putting on the shower or tap. Sometimes it's low when having a shower. I believe the water pressure is shared from next door to next door because it's a Victorian terrace property.
And I have seen the lead pipe out side, because the outside stop tap is connected to the other peoples property. If I turn off the stop tap the other properties will turn off in the street also.

The heating isn't that great at all, as it takes time to heat up from the radiators.

Plus the boiler is downstairs in the cellar which I want to move it up into the kitchen area.

I hope this information helps.

Kindest regards,
Moe.

 

[Last Plumber]

There is a lot more to this than replacing pipe with larger pipe.
When you say lead pipe, is this water mains or is the internal pipe to hot and cold lead too?
Do you know what size they are?
Are you doing this yourself entirely? Would you not be better getting advice from someone who has seen it?

 

[Moeen123]

Hi there the internal pipe for the main stop tap is lead pipe and outside too.

The lead pipe comes inside into the cellar. The lead pipe is then soldered to a copper pipe 15mm, which then connected to the boiler.

The lead pipe thickness is roughly about 25 to 30 mm thick.

The combi boiler is then in a mixture of 15 mm and 22 mm into the combi boiler itself.

I do know how to solder pipes and connect them

The lead pipe leads into the kitchen side and then is converted into a 15 mm copper pipe.

The rest of the upstairs is which the bedrooms and bathroom run into copper pipe.

In regards of doing the work.

I have spoken to some plumbers who are saying run 22mm pipe then converted down near to end at 15mm pipe.

But my question is, what is 28mm pipe used for?
Would it be best in for water pressure and heat up the radiators up quickly?

I do know how to solder pipes them and join pipes which is not a problem to me.

I was hoping for some guidance or advice.

I hope this information helps.

 

[Scott_D]

You won’t gain anything in terms of flow and pressure on hot and cold with a big pipe.
Best to get a new dedicated cold supply from the road to your property.

 

[SJB060685]

With regards to the heating system pipework they need to be sized correctly to carry the energy required for the radiators. Without knowing the boiler output and individual radiator outputs it’s hard to say what size pipe is required.
There is nothing wrong with oversizing the heating pipework a little, especially if you are considering a heat pump in the future. If you’re not considering a heat pump or the property isn’t suitable currently without major insulation improvements then the pipes should be sized to suit your current system demand. Again you could oversize but if it’s not needed now or in the future it’s a waste of money.

 

[Last Plumber]

The lead pipe at 25 - 30 mm will more than likely be 1/2" 9's. (could be 3/4" but I doubt it).
It is possible to improve flow rates if you have adequate pressure at the mains and you upgrade it to a larger pipe from ferrule to stop tap. If you wanted to improve the water main, I would recommend doing the whole job but only if your calculations deem that possible.

The heating side also needs calculating out as enlarging the pipes could prove pointless. There are a good number of reasons why a heating system can be sluggish. Do you know if it is a one pipe system for example?

You sound like this is a task you are willing to complete yourself which is fine but it also sounds like you need advice from an experienced person as opposed to a forum. It would be worth paying for that kind of advice in my opinion. It could save you a lot of wasted time and money.

 

[Ric2013]

28mm (1" bore approx") pipe is not likely to be used for mains water supply in most houses. Mostly used for gas runs, and for gravity circulation e.g. on woodburning backboilers or very old heating systems. If you had very poor water pressure for example if your hot water is gravity fed from a cistern, a thicker pipe would allow for better flow. In this case, the pressure/flow of your hot has nothing to do with your mains pressure and flow.

The size of your mains supply pipe also has nothing to do with your radiators warming up. The water in your radiators, while it may be topped up from the mains, is kept isolated from the mains water. A large heating system with a large heat output and therefore a lot of flow between the boiler and the radiators may use 28mm from the boiler and then reduce down to the individual radiators, not to improve radiator heat up speed, but to reduce the pressure required from the circulating pump, resulting in less noise etc. Most radiators will happily run on 15mm or smaller pipe, and (as part of a properly executed system) can actually heat up quickly. It could just be that the boiler takes a while to heat the water in the system?

The actual pipe sizing calculations are quite time-consuming and complicated; if you want to go down that route, it's a case of read a textbook as it's too much to explain on here (if you can find a professional willing to do a site visit and design your new system leaving you to do the work, that's another option), but if you want a real-world example, I have a customer with around 14 fair sized radiators in a house made up of two three-bedroom semis knocked into a single house. The heating system in that property uses nothing greater than 22mm pipe for its heating system (it's quite an old system that was installed well before my time - I have only modified it - and while it is possible that it is towards the upper end of the capacity for 22mm, I've never tried to calculate it as it works perfectly well.

 

[king of pipes]

A little more information would be of help here how many radiators in the property ? How many bathrooms? Ensuites? Hot water outlets ? , Is this a older terraced type property? the fact it has a lead incoming water supply leads me to this conclusion ? , Combi boilers have their place but are sometimes not the best option before jumping in with suggestions we need to know a bit more about the property and your intentions on the improvements going forward? . Regards kop

 

[Moeen123]

A little more information would be of help here how many radiators in the property ? How many bathrooms? Ensuites? Hot water outlets ? , Is this a older terraced type property? the fact it has a lead incoming water supply leads me to this conclusion ? , Combi boilers have their place but are sometimes not the best option before jumping in with suggestions we need to know a bit more about the property and your intentions on the improvements going forward? . Regards kop

The property has 10 radiators altogether in the property. The property is in end terraced house, Victorian house.
Its has 1 toilet and bathroom. But I was thinking of adding another bathroom with toilet in the attic, later in the future.

 

[Ric2013]

Doesn't sound like there is much peak requirement for water in such a property. Replacing the lead would be a good idea in principle, but I'd be surprised if 28mm were required on the supply side.

May be worth checking that the shared stopcock is fully open (anticlockwise as far as it goes and then clockwise 1/4 to 1/2 a turn) as sometimes people well-meaningly but wrongly leave them almost closed, and testing the mains standing pressure and what the working pressure is with a tap open to get an idea of how good or bad the mains pressure/flow characteristics are.

 

[Moeen123]

Doesn't sound like there is much peak requirement for water in such a property. Replacing the lead would be a good idea in principle, but I'd be surprised if 28mm were required on the supply side.

May be worth checking that the shared stopcock is fully open (anticlockwise as far as it goes and then clockwise 1/4 to 1/2 a turn) as sometimes people well-meaningly but wrongly leave them almost closed, and testing the mains standing pressure and what the working pressure is with a tap open to get an idea of how good or bad the mains pressure/flow characteristics are.

Hi there, what is the 28mm copper pipe used for?
Would this be used in large properties or is it certain amount of radiators in a house?
But does the 28mm copper pipe increase the flow rate to get to the radiators, shower taps and kitchen taps quicker?

Cheers,
Moe.

 

[king of pipes]

28 mm pipe is indeed used for larger heating systems , and multi bathroom properties a upgrade of the lead supply would be a good place to start , combi boilers for a family home are not really the way to go, and moving one can be a disappointment if it's more than 5 years old I'd consider upgrading to a system boiler and unvented cylinder this will require improvements to your incoming water supply larger pipework alone will not improve your system . Kop

 

[Last Plumber]

As Ric above said, worth checking the stop tap but to add to his comments:
If it is lead - unless the service provider has upgraded the main - it will probably be a plug cock. They only quarter turn and there is no stop so they can be left half closed or in some other random position by the untrained/inexperienced.

 

[Ric2013]

Hi there, what is the 28mm copper pipe used for?
Would this be used in large properties or is it certain amount of radiators in a house?
But does the 28mm copper pipe increase the flow rate to get to the radiators, shower taps and kitchen taps quicker?

Cheers,
Moe.

Thought I'd answered that in post 9?

Specifically, if you were using 28mm on the mains water supply, all that would do is improve the working pressure (i.e. pressure that there is in the pipe when there is an x litres per minute flow), and it may not improve it very much or even in any way that you would actually notice without laboratory test equipment. You might use 28mm if it were a very large house or number of flats, or something like a hotel where lots of people might be drawing water at once due to there being 5 bathrooms or whatever. Very unlikely in a 1-2 bathroom town house.

As far as radiators are concerned, the pipes should be sized correctly. Having oversized pipework would just increase the amount of water the boiler would need to heat before any heat actually reached the radiator. If your radiators are all taking an excessive time to heat up, the issue is more likely to be a pump issude or undersized boiler or, if the problem is just some radiators, the system probably needs what is often called 'radiator balancing' which is "just" a number of adjustments to valve settings.

Finally, as you refer to showers, I'm assuming you're talking about hot water. As you have a combi boiler, the pressure will be affected by the pipework diameter, but in much the same way that cold water is affected. What is the specific problem you are experiencing that you are trying to solve? My bath hot tap is run in 22mm, but as my hot water system is a vented cylinder, I have less than a third of the minimum mains pressure you are likely to have and I still get 20 litres per minute. No combi boiler will give that sort of flow as you are limited to how much water the boiler can heat in real time (unlike with a cylinder where the heat can be accumulated for later use) and, if it did, it is unlikely to be very hot water anyway.