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[Hysteresis]

My central heating is installed in a relatively new house (8 years old) and was installed by a professional contract company.
The system is piped with Hepworth pipe( HEP2O), 10mm OD x 6.5mm(approx) ID , using 'push fit' connectors.

1) I want to install a designer radiator of about 800W and the easiest way to do it is to install it in parallel with an existing radiator.

The existing rad is a double and is 1100mm by 600mm . Is this installation advisable as the original rad is fed with such a small pipe and I fear is that the new rad will 'starve' the original rad!

2) I intend using TRVs with the new radiator and the pressure of the Central Heating system is 1.5bar. Do you think this will be a problem ?

3) Whilst contemplating this addition I questioned the long term durability of Plastic C H pipes but more specifically the rubber 'O' ring seal used in the 'Push On' connectors.

My fear is that normal rubber deteriorates with time and that these 'O' rings are not normal rubber.
How long are these seals expected to last.?

 

[DP]

Wrong idea to tee into 10mm pipe. I would plumb into 22 or 15mm.

I almost always use copper as am regularly repairing 'plastic' systems that are clogged up. Only use plastic where copper use would be near impossible.

 

[Hysteresis]

Thanks DP
Those were my thoughts also but I am not a Professional Plumber.
Unfortunatly I am stuck with the plastic Pipe as that is what the Builder specified to the Plumbimg contractor.
Apparently the design was to run a 2 inch header in the ceiling space ie under the 1st floor boards. I think the correct thing to do for a new radiator installation would be to pipe from the header, but as You can imagine, exposure of the header is a major undertaking. I fear Mrs Hysteresis is in for some bad news.

 

[Terrywookfit]

2" header! You must have a large house.

 

[JPC]

i cant remember what 10mm pipe can deliver but 15mm does 6kw. if it only did 1/2 that its 3kw and thats more than you need for the said desc rads.
give it a go and be optimistic

 

[Hysteresis]

Thanks JPC - my concerns are not so much flow rate but because of the diameter of the plastic pipes and the fact that I would have to use 'Tees' that there would be a preferential flow to the existing radiator and therefore starve the new radiator rendering it ineffective. The trouble with giving it a go is that the new radiator will cost about £800, and if it doesn't work then it is a lot of money to spend on 'giving it a go'

 

[D_Hailsham]

Hepworth say:

As a general precaution, 10mm Hep2O® should not be used for a radiator output in excess of 1.5 kW (approximately 5,000Btu) unless proven by calculation

This is taken from Hepworth Design Considerations Manual page 60.

 

[BigBurner]

Wrong idea to tee into 10mm pipe. I would plumb into 22 or 15mm.

I almost always use copper as am regularly repairing 'plastic' systems that are clogged up. Only use plastic where copper use would be near impossible.

Why is this plastic pipe clogged up more than copper?

 

[Hysteresis]

Wrong idea to tee into 10mm pipe. I would plumb into 22 or 15mm.

I almost always use copper as am regularly repairing 'plastic' systems that are clogged up. Only use plastic where copper use would be near impossible.

Why is this plastic pipe clogged up more than copper?

I would presume that the possibility of clogging is far greater in the plastic pipe as opposed to the copper pipe simply because the ID of the plastic pipe is about 6mm whereas the copper pipe ID is around 14mm

 

[gigz]

my concerns are not so much flow rate but because of the diameter of the plastic pipes and the fact that I would have to use 'Tees' that there would be a preferential flow to the existing radiator and therefore starve the new radiator rendering it ineffective.

Not saying it will or wont work but you could closing down the lsv on the existing rad (see balancing in F.A.Q.)

 

[Hysteresis]

my concerns are not so much flow rate but because of the diameter of the plastic pipes and the fact that I would have to use 'Tees' that there would be a preferential flow to the existing radiator and therefore starve the new radiator rendering it ineffective.

Not saying it will or wont work but you could closing down the lsv on the existing rad (see balancing in F.A.Q.)

I think that is the probbable solution. Thanks Gigz