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Zone Valve positioning

View the thread, titled "Zone Valve positioning" which is posted in UK Plumbers Forums on UK Plumbers Forums.

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prs999

Hi,

I have just bought a new house, the heating is shot which I knew so we are ripping it out and starting again with a combi and a 2 zone system (upstairs and down)

The existing installation had the boiler upstairs in a cupboard but we want are going to move it downstairs to what will be the utility.

The question I have is where to put the zone valves, there is an option to put them upstairs where the upstairs and downstairs rads currently split or to stick them downstairs into what will be the new pipework from the boiler will run? does it matter in this case? will gravity have any effect? is there a maximum distance from the boiler they have to be?

Also does anyone know if Worcester Bosch Greenstar 34CDI has pump overrun? will the timer/zone valve controller automatically take this into account?

Cheers
 
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Hi there, the position does not realy matter. What you should consider is that you may not need zone valves, deppending on the size of the house. You should have the system split if the house is over 100 sqm. If you do have two zone valves then is good to have an auto by-pass to help cooling down the boiler when overruning, the auto by-pass should be at some distance from the boiler in order to allow the cooling down in that bit of pipework ( some two, three meter would be good).
All the modern boiler have overrun.
 
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Egidio


You can use another more flexible method of controlling your new system that will give you a zone for every room, fit Terrier battery operated TRV on each rad, they will cost your about £20.00 each, there is also a Terrier programming stick that fits into your laptop, £19.00, it has a very comprehensive and easy way of programming each valve, sit near each valve an the stick will download the times and temps you have set up in the FOC software, it's half duplex so it only programs one way, the software is breeze to use, if you have 8 rads it will cost you 8 x 20 £160.00 and you can tell you friendly Building Control Officer you have 8 zones in the house not the crappy 2 that the regulations suggest, you will still need a valve on the DHWS, BTW there are multiple time zones for each rad.

Best of luck, save the planet and save energy the easy way, no silly wiring plan systems, it's the future 😳

http://www.saveonheatingbills.co.uk/helpSupport/downloads.html

download HZ USB Stick software zip file and try it, use the help menu



And you will need one of these, ABV with a flow meter included , no more guessing how much water is going around the bypass, available from BES part number 18865 made by Honeywell DU 146 £48.00 all your problems solved in one foul swoop

18865.GIFhoneywell_du146__81079_std.jpg
 
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Thanks for all of your help, does the auto bypass have to be in the relms of a radiator or could I just tap a loop of 22mm pipe off before all of the zone valves and the return to allow for cool down? we will be installing a combi ans if I could loop some pipe through the back of a built in cupboard the mrs might give me less jip for removing the airing cupboard!
 
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Always look at the manufactures instructions, its all on tinternet, click google below
what the hell did we ever do before tinternet, I can't remember



Google

As close to the outlet side of the pump and then back into the return as close to the boiler as possible, rough guide, like the drawings show
 
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Thanks, I have tried to find out the info on the net with no definitive answer in regards to the specific boiler so I have emailed Worcester Bosch, I will post the reply here if I get one
 
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The installation of terrier valves in every radiator is a good idea specially in the bedrooms, but that will not provide boiler interlock. In that case radiators will be shut but boiler will carry on working for as long as the programmer is on through the by pass. The by pass should be installed before the motorised valves because that will open when motorised valves close for boiler overrun in order to cool down.
 
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Egidio said:
The installation of terrier valves in every radiator is a good idea specially in the bedrooms, but that will not provide boiler interlock. In that case radiators will be shut but boiler will carry on working for as long as the programmer is on through the by pass. The by pass should be installed before the motorised valves because that will open when motorised valves close for boiler overrun in order to cool down.
Click to expand...


Sorry you know much more than me about the HVAC industry and hydraulics can't help you anymore, hell 10 post and a full blow plumber, what a Forum, why did I waste 55 years of my life

Bye
 
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Egidio said:
The installation of terrier valves in every radiator is a good idea specially in the bedrooms, but that will not provide boiler interlock. In that case radiators will be shut but boiler will carry on working for as long as the programmer is on through the by pass. The by pass should be installed before the motorised valves because that will open when motorised valves close for boiler overrun in order to cool down.
Click to expand...

I for one would be using a room stat down stairs,and upstairs programmable TRV's,yes I know the boiler shuts off with the room stat,but most building inspectors wouldn't have a clue anyway,but I can guarantee the heat exchanger on the combi will last far longer,and will run quieter,dont mind multiple zones on unvented, system boiler installations,but on a standard combi installation its hard to be competitive,and up our way I know that over a 100 fits a week are going in on local authority houses all unzoned
 
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Hi,

The main reason I am going zoned is to save energy and money in the long run, we currently have a trv only setup in the house we are in at the moment and we still seem to be heating the whole of the upstairs as well as the downstairs for no reason. yes you can adjust the trvs to balance this out but this would mean daily adjustments, having 2 separate zones would automate this a lot better for not a huge extra installation cost, I know as an installer the cost of this will probably price you out of a lot of jobs but as an end user making this decision I am happy with the cost implications

Thanks
 
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prs999 said:
Thanks for all of your help, does the auto bypass have to be in the relms of a radiator or could I just tap a loop of 22mm pipe off before all of the zone valves and the return to allow for cool down? we will be installing a combi ans if I could loop some pipe through the back of a built in cupboard the mrs might give me less jip for removing the airing cupboard!
Click to expand...


As promised Worcester Bosch's response to the above

[FONT=&quot]A bypass will be required. This could be a copper pipe as far from the boiler as possible, but it would be more effective if a radiator was kept off the zone system to dissipate the heat for obvious reasons. This is subject to customer comfort, of course. A towel rail is usually a good example. [/FONT]
[FONT=&quot]Regards,

I will ask Worcester but do you think this a towel rail would need a bypass relief valve on it as well if it was not to be used as a main source of heating?

Cheers
[/FONT]
 
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In order to save money and have a good installation you can as you intend to anyway, the auto by-pass could be replaced for a towel rail in the bathroom as Prs999 suggested the only thing is that you have to run separate flow and return from before the motorised valves. Both zones can be controlled in temperature and time and both interlocking with the boiler.
Don't make the mistake of just fitting trv's everywhere because on that zone the thermostat will reach temperature and if that happens the boiler will carry on working even if all the radiators are closed.
trv's should be fitted specially in bedrooms and closed rooms, open areas where the thermostat is should be controlled trough the thermostat and ideally if the system is well designed and balanced, then all rooms in the same zone should heat up more or less at the same time.
 
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Sorry to butt in its 150 sq metres, so a standard semi would be just under (75 sqm downstairs and 75 sqm upstairs)
Egidio said:
Hi there, the position does not realy matter. What you should consider is that you may not need zone valves, deppending on the size of the house. You should have the system split if the house is over 100 sqm. If you do have two zone valves then is good to have an auto by-pass to help cooling down the boiler when overruning, the auto by-pass should be at some distance from the boiler in order to allow the cooling down in that bit of pipework ( some two, three meter would be good).
All the modern boiler have overrun.
Click to expand...
 
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Egidio said:
you may not need zone valves, deppending on the size of the house. You should have the system split if the house is over 100 sqm.
Click to expand...
kozak1968 said:
Sorry to butt in its 150 sq metres, so a standard semi would be just under (75 sqm downstairs and 75 sqm upstairs)
Click to expand...
Up to 150m2, 2 zones with separate thermostatic control but on the same time control.
Over 150m2, split zones with separate thermostats and separate time control for each zone.
(different for single storey)

http://www.planningportal.gov.uk/uploads/br/domestic_building_compliance_guide_2010.pdf

Page 22
 
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Hi,

thanks

Firstly to defend Worcester bosch he did point out in a later email that he is only stipulating what the boiler needs to function as designed and not the regulations.

my current thoughts on a design are:
Boiler output to valve location (about 4 or 5 meters) then tap off before zone valves into bathroom radiator/towel rail and also a separate 22mm pipe in the cupboard with a bypass valve to allow the bathroom rad to be balanced a little and incase it is ever turned off. Then into the 2 zone valves for up and down and trvs on all of the rads.

The top floor stat will go on the landing outside the bathroom door? and the ground floor in the lounge? my thought was to put trvs on a all of the ground floor rads as well and then just removing the stat head in the room with the wireless thermostat in, leaving it constantly open?
My thinking being that if we ever change the way we decide to use the house (e.g. a log burner later, room use change) I can just move the thermostat and rad valve top into a different room and I won't have to drain the system to move the whole trv

Any comments or suggestions would be appreciated
 
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The only thing you should be aware is that with trv's everywhere soe people adjust the trv's instead of adjusting the roomstat and I have seen many many cases where boilers have been working with all the trv's shut throught the internal by-pass. I would fit two lockshield valves in the towell rail to prevent someone from closing without the need of a tool.
Good luck!
 
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Even if your house in not bigger than 150m2 and you don't have to install separated timer I would probably do it if you think that you gonna require heating times very diferrent one from another (ex: heating all day Saturday and Sunday in living space but not in the bedrooms, or work from home, etc).
You can also programable stats so you can control time and temperature separate in one unit.
I like the honeywell CM927 (7 day programmable stat)
CM927 7 Day Wireless Programmable Thermostat - Honeywell UK Heating Controls
 
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