Is it possible for the heating engineer to install a WB 28i to supply the DHW and several months later connect the CH piping i.e are there two separate circuits?
- posted
15 years ago
Is it possible for the heating engineer to install a WB 28i to supply the DHW and several months later connect the CH piping i.e are there two separate circuits?
Yes.
Thank you John, a succinct but helpful response.
After some cogitation I realised that I knew that there was two separate circuits but I was unsure if there were any controls or pipes within the boiler which needed the presence of the central heating water.
My neighbours are having an extension built to their bungalow and wish to replace their instantaneous water heater and gas fires with a combi boiler. I think that they did not wish to demonstrate their lack of knowledge by asking their builder this question.
Replacing their water heater with the combi should be a fairly quick job since all the piping is already in place. I assume that it will be the central heating connection which will be more time consuming. Now all they need is a flexible heating engineer.
Many thanks.
PJ
Heh!
Yes, the long(er) answer: you'll need to fill up the primary (CH flow and return) circuit to allow the boiler to work (without China Syndrome effects :-))
Thank you again, John.
I would leave this sort of task to someone who would know how to install a filling loop. I would not even recognise one.
However, I am intrigued by your China Syndrome scenario as geothermal energy might provide some cost savings, as well as import opportunities. PJ
The problem you face is to pressurise the primary side of the system, the hot water is generated in the secondary heat exchanger
TBH, I would have thought that the additional work involved in plumbing both sides would not be that much more work, if properly prepared
Thank you Geoff for your advice. I am beginning to realise that it would be much simpler to prioritise the installation of the final radiators so the DHW and CH can both be connected at the same time.
PJ
Your choice but it's not that much work to get the DHW going with stub CH pipework - I just do tails from the boiler flow and return going down the wall from the boiler by about 1 metre and either cap them off or link them together by a bit of 22mm plastic.
BTW the optional filling link is only a few quid and saves on extra junctions and fittings for a hose-type filling loop.
I have a 28i Junior and the filling loop sits in a relatively inaccessible location behind the boiler itself
I have left it open and installed another one in a more accessible location
Dunno what john has to say about that, as an installer
Thank you John. I was wondering how the boiler could be pressurised if there was just the two tails fitted.
It looks much simpler, cheaper and neater to fit the WB filling link than to have the traditional flexible loop.
I am most grateful that you share your knowledge and expertise. I think that you have solved my problem.
PJ
Sounds reasonable to me!
yup
I didn't fit them for ages because I just assumed they'd be some stupid price. When I found they were under a tenner I was kicking myself!
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