Retrofitting a upstairs and downstairs zones, to existing CH system

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Hello all - ive been researching as best i can, but wanted to confirm with those who have more experience if this works. I want to retro fit my current CH system into 2 zones (upstairs, and downstairs - FYI i have considered smart TRVs but, the house is old, and the runs long, so i need to cut down the distances and insulate the hell out of the downstairs). I think it works - subject to balancing, wiring of zone valves, nest stats etc, but welcome thoughts if anyone has a moment? Thank you in advance - Dave


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First quickie- do you have a hot water cylinder to worry about?
Second one- is there a bypass on the system anywhere (either an actual bypass link between flow and return or a rad with 2 lockshield valves)
Third, hopefully there's more than 1 rad upstairs, if not then the boiler will start cycling with such a small load.
Def insulate the pipework in unheated areas (ground floor voids, loft), if you can easily lag pipes under 1st floor floors then do so, if not don't get too upset, you are still getting the benefit of the heat.
Do have a think about the extras you can get from smart TRVs Vs traditional zoning. For instance (this is with the Drayton Wiser TRVs) I have the bathroom set to a tropical 20 degrees for morning shower time, goes off in the day while house is empty, back on at 16 Deg of an evening (so it's not freezing when you nip to the loo). The real kick is how well they work with Alexa etc. if you want a quick boost (or if you're heading out for an unscheduled away)...
 
Oldbutnotdead - thank you very much for your time. Chortled at your reply - "tropical 20 deg"... wish my wife thought 20 deg was tropical! She unfortunately likes her skin to blister in the shower, and still wears a jumper on as 30 deg summers day! Now to your questions:

1. Yes we do have a HW cylinder - its by the boiler (i omitted it to try and keep the diagram simple)
2. Yes we do have a bypass valve at the Boiler - didnt know what one looked like before, but now i do, and i can see it between the flow and return
3. Lol - yes, we have a few more rads upstairs (again, trying to simplify!)
4. Yes, whenever we have had work done, or a carpet up i have insulated, but it is so difficult. We live in a very old house (single glazing, no cav walls, minimal insulation), with long runs, and rennovating bit by bit, but i still think there is masses of heat lost warming voids under the floor!
5. Re smart TRVs - i will continue to have an open mind. Its just if i have 1 rad coming on - i fear it wont be as efficient in a modern insulated home, as once all the pipes are heated up, you may as well be running all the radiators, because of the length of the runs.

Is it ok for the new flow and return to t-off per the drawing above? And is it a problem having 4 dead ends where the existing pipes get cut and capped? Thank you again for your time and thoughts OBND! Dave
 
Re the flow and return- are you planning on having the hot water cylinder as a separate zone? Either way, make sure that the return from the cylinder is nearer the boiler (pipewise) than your new tee, otherwise you can end up with some strange reverse circulation effects.
If the bypass is at the boiler (before any of your planned motorised valves) then that's fine- some boilers have the pump run on after a firing to cool the heat exchanger, bypass ensures that even if all rads are at temp (or all zone valves closed) water can circulate in the boiler to do that job.
Yes you'll get a bit of wasted heat if only 1 rad is demanding heat- is the boiler fairly modern? Cos modern boilers monitor the return water temp and derate (modulate) accordingly to run most efficiently. I too was a bit skeptical about WiFi TRVs instead of zone valves but the convenience and flexibility is worth whatever energy I'm losing (and I don't think I'm losing much cos it is so easy to mess with schedules and temperatures). If you have carpets on the first floor, it doesn't take a lot of energy to raise the void temperature- def make the effort to insulate ground floor pipes though.

One other little bonus of the Wiser kit (not sure about others)- you can disable manual control (both of the room stats and the WiFi valves), handy if you are sharing a house with persons who like to wander about in shorts and t shirt with the window open and turn the heating up to full! And the valves have a draught detection setting- blowing a gale in the back bedroom? Knock the rad off :)
Dead ends/legs- keep them as short as possible, eliminate them if possible. Not a health problem in a sealed system but poor practise and you can end up with air bubbles stuck in them which are an irritant.
 
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Yes! That should work ok ......If it is working now.
Dead legs are not good so keep them as short as possible and /or bleed valves.
Where is pump and m/v's on system,
 
OBND - thank you again! To your queries:
- Yes, HW cylinder is on a separate Zone
- The T will be a long way away from the return - noted re "reverse circulations"
- The boiler was fitted c2 years ago, and as modern as poss back then
- I will take a closer look at the Wiser kit (with an open mind!) - it sounds pretty flexible. Chortled re ref to "open window" - pretty much all our windows are open (despite being closed) / old sash windows ugg!

Terrywookfit and OBND - will keep them short, and the bleed valve is a great shout.
- The pump and m/v's (motorised zone valves?) are all by the boiler
- Pleased to hear that conceptually it works in your opinion! ;)
 
Sash windows- a cheap winter bodge is make some frames (use slating batten or something cheap) sized to fit the window reveals, cover them in polythene, edge them with sticky back draught strip (doesn't scuff the paintwork so much), push fit and you'd be surprised how much warmer the room feels.
 
Sash windows- a cheap winter bodge is make some frames (use slating batten or something cheap) sized to fit the window reveals, cover them in polythene, edge them with sticky back draught strip (doesn't scuff the paintwork so much), push fit and you'd be surprised how much warmer the room feels.

OBND - i am going to try this next Autumn/winter - if i can afford the cost of the timber by then! ;) p.s. sorry for the delay, COVID finally got us!
 

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