Combi Boiler

[StuDH]

I have a 1960's house. The central heating consists of one single run of pipes, with the radiators 'sitting' on it. I want to have a combi boiler fitted, but have been told that the pressure used with a combi would blow the existing joints, and I will have to replace all the pipes and radiators.
Is this correct ?

Thanks Stu.

 

[corgiman]

is it is correct

get them pressure tested before installing the boiler.

 

[Terrywookfit]

Even if the pipe work is sound you will not get good performance from your boiler as the return temperature will quickly rise and stop the boiler condensing!!

Chances are it was only installed as background heating!!

It would seem to be a good time to upgrade to a two pipe system!!

 

[bengasman]

Unlikely a condensing boiler, as is compulsory now, can be commissioned on a one pipe system. Nothing to do with too much pressure but with how they work

 

[Agile]

Actually if the rads give enough heat output that as long as the flow rate through the one pipe is adjusted to give the 20°C differential it will work quite well.

The limitation is just that the rads at the end of the loop will only be at 55° or less.

In practice some additional heat emitters on the ground floor to boost the heat output will allow more heat spill to the upstairs and lessen the effect of the low rad temperatures at the return end.

Of course you cannot have TRVs very effectively on a one pipe system.

In practice in a small property its often better to take the opportunity to replace all the rads and pipework when the new boiler is fitted.

Its the normal method in a commercial property to have a one pipe system though.

Tony

 

[StuDH]

I have a 1960's house. The central heating consists of one single run of pipes, with the radiators 'sitting' on it. I want to have a combi boiler fitted, but have been told that the pressure used with a combi would blow the existing joints, and I will have to replace all the pipes and radiators.
Is this correct ?

Thanks Stu.

Thanks for your advice.

Would an alternative be to forget the Combi and fit a New Condensing Boiler to the existing system?

Thanks Stu.

 

[simond]

If you want a combi, go for one.

We have installed a number of combis/condensers on one pipe systems, you chosen manufacturer would be pleased to confirm suitability.

There is no reason why it should work less well than the old unit did heating the rads, there is still a temp drop across the f&r pipes.

Your fitter will want to fit TRVs to bedroom radiators (to meet building regs), make sure that these are the (more expensive and not kept on the shelf) full flow types designed for one pipe systems.