Central Heating Diagram

[shivys]

I need to do a central heating pipe network under the house, just wondering if it matters the hot going to the radiator pipe with the valve or to the radiators normal pipe ?

Please explain why ?

System is a normal condensing boiler with expansion vessel.

thank you

 

[Dan Robinson]

the hot going to the radiator pipe with the valve or to the radiators normal pipe
thank you

try that again in English....

Are you talking flow and return?

In which case it can matter very much. It can matter very little depending on the type of system you have,

There are few systems that can be counted as normal.

Combi or Cylinder? that will have the greatest bearing on the importance of which way round rads work.

If the latter.... S or Y plan?

Open vented or sealed?

Open or Unvented?


Chuck us a bone eh fella?

 

[shivys]

Sorry I meant to say flow and return.
the flow = hot for me, return = cold.
some radiators have 1 hand valve on each side, so I guess it doesn't matter, but some others have the hand valve on only one side, so is there a problem from where the flow come in ?
The system is a basic combi/boiler and i think the expansion vessel is inside the machine, says the manual.
thank you for your help

 

[Dan Robinson]

Can't the chap installing the boiler guide you?

Which side the trv goes on depends on the valve body. The instructions will tell you.

 

[gsplum]

It doesn’t matter which side you connect the hot and cool lines too. If the (thermostatic) value is closed, nothing can flow in but I would try to connect all hot pipes to the (thermostatic) value for simplicity. If your problem is piping (for some reason you cant reach the right or left side of the radiator) in most cases I have seen you can remove the value and place it on the other side. Rads typically come with 4 holes to tap..

Some new combi do indeed have expansion vessels but they will have limits based on their capacity. You might want to put an external one in too, that depends on your pip design and total system pressure, and planned max operating temperature.

 

[doitall]

It doesn’t matter which side you connect the hot and cool lines too.

Some TRV's are not bi-directional so it matters

You also need to know the flow for zoning etc.

 

[gsplum]

Some TRV's are not bi-directional so it matters

You also need to know the flow for zoning etc.

Good point!

Wonder these days if zoning is really necessary, for most situations if you fit TRV on all the rads, you can set them low (or off) in rooms not in use. Most houses dont have that many rads/ rooms..

 

[Agile]

Its a long time since I saw new TRVs being sold which were not bidirectional.

However, I always feel that they work better when fitted on the flow.

Tony

 

[gsplum]

Its a long time since I saw new TRVs being sold which were not bidirectional.

However, I always feel that they work better when fitted on the flow.

Tony

I agree. I read that there is a theoretical argument about locating the TRVs on the return so as to minimize temp reading error from the hot 'flow' pipe but in practice it really make very little difference.