Zoning Heating System - Novice Needs Help

[johnw23a]

Hi, i'm new to the forum and am not a plumber, although very competent in plumbing and general pipework. I have just knocked my kitchen and dining room into one and there are no ceilings, added to this, I have easy access to the heating pipes upstairs, so I am making use of this easy access to split my upstairs and downstairs into two zones. I am due to be made redundant next week and cannot afford a plumber to do this, I have had 4 quotes, all too expensive, I have all materials already purchased and at hand with plenty of time.

The situation and my idea of how it will work.

I have a combi boiler for dhw and central heating. The boiler is located in my garage with pitched roof above, joined to the main house.
I want to use the existing circuit (22mm) for upstairs, obviously capping off the 15mm drops for downstairs and the new circuit for downstairs heating.
I plan to run an extra 2x 22mm (flow and return pipes) for the new downstairs zone and add 2x honeywell single port zone valves in the roof space in the garage attic above the boiler - is this correct ?
I have been told that I can have 2x separate flows with 1 return, but in my mind this is wrong, I would have thought that if both systems were in use at the same time, this would reduce the flow around the system unless I had a larger flow pipe.

Any help would be gratefully appreciated, but sarcastic comments, i.e. get a professional etc. will not.

Many Thanks

John (new member 24th July 2011).

 

[SafeGasInstall]

....I got my self a new engine for my car (911) along with other bits which I will be willing to change but can not afford a mechanic to do it so I am taking a day off and going to my local mechanic for a day just to watch how do they do it and after I will be doing it my self (why would I want to pay him when I can do it my self )
s why do not you ring one of them plumbers to have you for a day out with them on installation job ,and then you can see how things are done and do your central heating zoning
try it will work ,just be polite and honest and they will help you !

 

[diamondgas]

Hi John,
If it worked ok b4 on 22mm then it should be fine as described. May pay to have zone valves in easy access for maintenance however. How do you intend controling the valves?

 

[johnw23a]

Hi Steve,
Thanks for your reply, it was very comprehensive, I'm doing some further research at the moment and may need to clarify a few points with you if thats ok.
Cheers
John

 

[johnw23a]

Thanks for your reply, very interesting and an excellent way of gaining experience that I had not thought of. Cheers John