question on Central heating

[Bambergaspipe]

[
I think you are getting confused by the differential temperature of the flow and return and the simple return temperature!

The return needs to be about 55°C to get much conddensing.

Tony

You are correct ,I`m not confused, I worded my response badly. If you are being petty you may want to spell better

 

[Balenza]

Not mine you Just stating my findings.

What does that mean? not really an answer was it? if you are going to just paste figures from a text book, please have the **** to back them up,

Why would I want to back them up to an a@ss hole like you ?

MOD 2

calm it down the pair of you

 

[Balenza]

MOD 2






??

 

[ashfordtown]

My I have opened a can of worms. Bit of background info, the system at present is a fully pumped one. The house is a large three bedroomed victorian end of terrace house double glazed windows. The house takes a while to heat up when its cold so the rads will be replaced with bigger size then are fitted now. The reason why I asked about using 28mm was I am aware that if the pipes to rads are too small there are problems getting the rads hot and I didn't want the same to happen with the new installation hence the 28mm question, the back boiler will be disconnected.

Steve

 

[gas4you]

My I have opened a can of worms. Bit of background info, the system at present is a fully pumped one. The house is a large three bedroomed victorian end of terrace house double glazed windows. The house takes a while to heat up when its cold so the rads will be replaced with bigger size then are fitted now. The reason why I asked about using 28mm was I am aware that if the pipes to rads are too small there are problems getting the rads hot and I didn't want the same to happen with the new installation hence the 28mm question, the back boiler will be disconnected.

Steve

I gave my professional opinion/answer as to how I would do it. Check your heat loss calculations again and then you can decide who to believe. I'm keeping out of all arguments

 

[Balenza]

gas4you wrote

In theory text book says about 45,000 btu for 22mm.

Yeah the old text books based on 11 degree differential.
As I said its a shame most installers dont know or take time to do the calculations and lash in oversized piping when their is no need. !

 

[Agile]

Yes, but oversized pipework still works whereas undersized does not!

Its rare that I ever see oversized pipework in London.

Only about 1 in 10 of the newish boilers I see have an adequately sized gas supply pipe.

At the extreme I saw an underfloor system using 94m length of 8 mm copper tube.

The boiler was on for 20 minutes and the return was still almost cold!

Tony

 

[Balenza]

Agile wrote

but oversized pipework still works wheras undersized does not.

Not necessarily.!
Some pipe sizing disicipines for certain mediums are critical and oversizing will result in system failure.

 

[Balenza]

Agile wrote

A typical three bed house requires about 10-12 kW

As this is another diynot forum riddle I shall assume these homes are no larger than 1200 sq feet.
Typical three bed room homes where I come from can be anything from 1700 to 3200 sq feet.