Using 15mm plastic pipe on an old 10mm copper installation.

[Ant1]

Hi all,

I am planning to install a new radiator and would need some advice.

1) All radiators currently installed are connected through 10mm copper pipes, I am planning to use 15mm plastic pipes as the radiator will be a fair distance away (around 10m of pipe is required to get to the radiator, and 10m back). It seems it should not be a problem mixing 15mm pipes with a 10mm installation, as long as I re-balance the system once the new radiator is installed. Could you please confirm?

2) Below is a photo of the 10mm manifold:

10mm Manifold

• Ant1
• 1 Jul 2016

Can I simply connect 10mm copper pipe to the manifold and then convert to 15mm plastic pipe using a Speedfit Reducer 15 x 10mm?

Speedfit Reducer 15 X 10mm

• Ant1
• 1 Jul 2016

I did my calculations making sure that the boiler can support enough BTUs for all radiators and hot water, however I am concerned about the flow as it is an old Baxi Bermuda 552 Back Boiler with a Grundfos 15-50 130 pump.

Do you think that installing this new radiator should not have any particular effect on the current installation? i.e. should all the radiators heat up properly?

Thanks,
Ant

 

[Ant1]

Any advice anyone?

 

[ScottishGasMan]

One extra rad shouldn't make any seriously noticeable difference to the boilers ability to heat the system.

Yes connect to manifold assuming you can get fitting that will connect to that manifold use reducer and then run your 15mm plastic

Be aware tho if the system water is particularly dirty when you drain it down that refilling may be a nusance and dirt loves to stick to plastic.

As far as balancing goes, if system is ok just now, fit new rad, close off one valve to new rad and open it 1/4 turns until it starts heating at the same rate as others, with a bit of luck you won't need to alter any of the other radiator valves

 

[Ant1]

Thanks a lot, I already got the correct fittings to connect 10mm copper pipes to the manifold. In my case I am only using 15mm plastic pipes due to the distance of the radiator (around 10m away) and in case I upgrade the system in the future, I will already have 15mm pipes running under the floorboards for this specific radiator. However I could also install 10mm pipe, at the end of the day it would be a similar job, may be a bit easier as won't need a reducer (just a bit more expensive in material).
What would you recommend considering this is a very old installation? i.e. carry on using 10mm copper pipe for this additional radiator? or using 15mm plastic pipes is safer considering the distance?

 

[Agile]

Microbore systems are largely self balancing due to the larger flow resistance of the 10 mm pipework.

In view of the long distance to this new rad you should use 15 mm tube.

In all probability you will not need to do any balancing at all.

You don't say the size of this new rad, but if in the usual range of 1.0 to 1.5 kW it should not create any problem. Note that all rad power outputs are now measured in kW. BTU is an old Imperial unit which was phased out in 1980 although a few older people who have not kept up to date still think in BTU.

Your system is designed for a flow temperature of 80 C and a temperature differential of about 11 C but that is not very critical at all.

It will not be necessary, but if you wanted to measure it you would need a contact thermometer. The IR types are NOT suitable because they give unreliable readings on pipework.

You should be able to easily judge when the return is slightly cooler than the flow.

Furthermore if you ever decided to upgrade the system and to convert to 15 mm pipework then that rad is already supplied with 15 mm.

Tony

 

[Ant1]

Thanks Tony, this makes sense to use 15mm pipes, specially since the radiator (not purchased yet) is 2100 kW (around 7300 BTUs).

 

[Agile]

No, it is not 2100 kW, it will be 2100 W or 2.1 KW.

Forget about BTU! Thats an old unit for those who are unable to manage current units. They still buy petrol in gallons and measure in feet!

In that case even more reason to use 15 mm tube.

 

[Ant1]

Sorry you are right Tony, this is 2100 W, typo from my side.