Unvented system

[lenny]

Hi,
On an unvented system can the central Heating circuit be ran through a cylinder coil? If it can would it require a cylinder stat and motorised valve to prevent the cylinder from over heating?

Many thanks

lenny

 

[Mushybees]

You don't have your G3 ticket so you shouldn't be touching an unvented cylinder unless it's under 15ltrs.

 

[lenny]

I take it you dont know the answer to my question then mushy. What are forums for?
Who said I was installing the cylinder? All I wanted to find out is it possible to tap into the flow and return on the central heating system and run it through the cylinder coil? ***

 

[Plouasne]

I take it you dont know the answer to my question then mushy. What are forums for?
Who said I was installing the cylinder? All I wanted to find out is it possible to tap into the flow and return on the central heating system and run it through the cylinder coil? ***

Lenny,

Can I say to you, what I used say to my apprentices, think once, think twice, think thrice, before asking the question, think about what you have asked, and come back to us if you haven't found the obvious draw back to your question

 

[lenny]

Hi Plouasne,
I have thought about the question... I cant see it being a problem, the cylinder would act like an additional radiator, when it gets up to temperature set by the stat the motorised valve shuts to prevent the cylinder over heating, the water then by-passes the cylinder until the the temperature drops, the motorised valve then opens again and so on..... Have I got this right or am I a million miles away?

 

[Plouasne]

Well I would say that you are a quarter of the way there, but the biggest fault/drawback would be that the cylinder would rob the heating circuit of just about all its heat, when the cylinder was asking for heat

 

[lenny]

Oh dear, have you any alternatives I have a large Ideal standard oil boiler, hot water on demand. It only has central heating flow and return. We shut it down in the summer and get our hot water from a twin coil cylinder that is sourced by solar. It also has an immersion heater. The central heating system passes the cylinder with the unused coil. Thats why I want to tap into the central heating system. Would it be a good idea then to use the immersion to heat up the cylinder in the winter at night when the electricity is cheap, backed up during the day by solar and the central heating.

The house Is quite large the hotwater from the boiler would supply the ground floor and the cylinder would take care of the rest of the house, there is a valve to split it.

Am I getting warmer?

Lenny

 

[Mushybees]

I take it you dont know the answer to my question then mushy. What are forums for?

Sorry, I didn't mean to be so dismissive.
When you see regular topics like the one asking if it's possible to re-solder a joint you can hardly blame me.

They say assumption is the mother of them all but on the internet it's best to err on the side of caution.

 

[traineedrip]

Sorry, I didn't mean to be so dismissive.
When you see regular topics like the one asking if it's possible to re-solder a joint you can hardly blame me.

They say assumption is the mother of them all but on the internet it's best to err on the side of caution.

If thats aimed at the thread i posted earlier then theres obviously a minimum level of experience needed before you can post on this forum. please explain what it is.
otherwise stop knocking people who are trying to learn.

sorry to go off topic

 

[lenny]

Hi,
On an unvented system can the central Heating circuit be ran through a cylinder coil? If it can would it require a cylinder stat and motorised valve to prevent the cylinder from over heating?

Many thanks

lenny

 

[newbie1]

are you installing this or is it your own or just a general enquiry
i only ask because it seems a very strange question for a qualified plumber to be asking

the cylinder would have to have a stat otherwise how would it know when the water has reached a safe temp and without a valve how would you control flow through the cylinder
can only assume you are talking about a system boiler which is pressurised with no f/e in the loft

 

[david williams]

i thought it was a oil fired combi

 

[lenny]

Hi

It is an oil fired combi .

Thanks
Lenny

 

[danielp]

well by doing this every time the hot water wants heating up your ch probs wont work atall

 

[Mushybees]

If thats aimed at the thread i posted earlier then theres obviously a minimum level of experience needed before you can post on this forum. please explain what it is.
otherwise stop knocking people who are trying to learn.

sorry to go off topic

I'm not knocking people trying to learn. My point was that prior to that thread you posted I thought you were a plumber.

Assuming someone's skill level when giving advise on something like unvented cylinders is a dangerous game so I don't do it.

 

[traineedrip]

I'm not knocking people trying to learn. My point was that prior to that thread you posted I thought you were a plumber.

Assuming someone's skill level when giving advise on something like unvented cylinders is a dangerous game so I don't do it.

You just made my day! I must be learning something then!
Everyone on here is at a different level with different experiences and i appreciate its not easy to know over the net.
By all means knock anyone who dosnt respect their own limits, or the unvented bombs, but i wasnt doing that so picking on my thread which was well within my limits is unfair. I shall hush now and enjoy the headyness of being mistaken as a plumber after 6 months study!

 

[Plucky]

If you wanted to plumb an unvented cylinder into a combi you would be better off giving it a pair of primaries for its own. Will give you more control and easier to balance. As others have said it will just drain the heating circuit.

 

[lenny]

Its a big boiler takes care of 15 Castiron rads no problem. The cylinder is also heated by solar. Theres still a bit of sunshine in Northern France in autum, winter and spring. Also with cheap rate electricity at night. All this combined, It should be a hit.... what do you think?

Newbie, just for the record, Im a property developer I mainly specialise in barn renovations. I have Plumbing city and guilds qualifications, I do all my own Plumbing, I get Heating Engineers in to do any heating. whats up with trying to pick a few brains on this forum. So whats strange about my questions????
Wheres ya handbag?

Lenny

 

[Plouasne]

Lenny,

Why did you not say that the job was in France?, the regs are slightly different, and if its a proper "Ballon avec deux serpents", in steel, it will make it easier, if its a UK sourced model I am afraid you are stuck, because I do not know enough about them things, trop complique pour moi

What I would do in your case, on the flow fit a 3 way motorised valve, so that when the cylinder asks for heat, the valve will open mid way, to allow both heating and hot water to be satisfied, when the cylinder is satisfied, the hot water side of the valve closes, I will leave you to work out the electrics, pump etc, shout if you get stuck

Solar to the bottom coil, boiler heating to the top coil, with electric only on heurs creux, (over night) to top it up if needed

 

[lenny]

Plouasne,
Thanks for that, the cylinder is a 300lt Kingspan ultrasteel from UK. Would this be a problem? Would a two port motorised valve connected in the flow to the coil and wired to the cylinder thermostat do the same job?

Thanks
Lenny

 

[Plouasne]

Lenny,

Just had a look at the kingspan cylinders, and I would do the "Y" plan set up rather than an "S" plan

Now a few words of "warning" or advice, 15mm tube forget it (it can be got to special order by a few proper merchants) 16/14 tube would be the closet, make sure that you back up on motorised valves, immersion heaters, pressure valve, etc they are completely different in France, and its a return trip to the UK for spares, the only thing the same would be the iron threads and these are mostly parallel, and not taper threads, hard solder is the norm for water, not soft solder, gas work is silver solder by law

Hope that you do not mind me asking how well up are you on French electrics ??another thing that is completely different, radial not ring mains, no flat twin and earth, earth conductor to be the same size as the phase and neutral, no PME, on the fuse board both the phase and neutral to break when the fuse trips, top feed to the fuse/trip, and if re-doing a property, all electrical, telephone, and TV, incoming services to be grouped in one place, in a Gaine Technique Logement (G T L)

 

[justlead1]

Hi I read the posts with interest. Am i right in thinking that an independent two port motorised valve should be fitted to the flow of the coil , controlled by a high limit thermostat to protect the cylinder from over heating?

 

[billybongo]

On the subject of unvented cylinders are you allowed to tee into the hot for a shower supply without being certificated , does this come under the unvented regs ?
excuse my ignorance but it seem straight forward and does not as such affect all the safety aspects already in place , cheers

 

[Plouasne]

I would like to run this past my peers and see what they make of it

Briefly, a solid fuel boiler with central heating and hot water, installed where there is a distinct possibility of at least one or more power cuts that could last a few days or more, in the winter months

If the boiler is a 4 tapping boiler, use the opposite top and bottom for the heating flow and return, use the other bottom tapping for the cold feed, and the other top tapping for the flow to the cylinder, heat leak (an un-valved radiator), continue the flow as the open vent pipe, with a high level "Tee" for the heat leak, dropping to the rad, on the branch to the cylinder fit a power close motorised valve, the return will pick up the heat leak rad return, then drop to an "injector " or venturi "Tee", just after the pump on the heating return, the pump to be controlled by a strap on pipe thermostat to avoid cooling the boiler too much before the boiler has got up to heat, and possibly causing corrosion of the boiler shell

The general idea for a power close motorised valve is that in the event of a power cut the motorised valve will open and help to dissipate some heat, also with the pump on the return with an injector "Tee" just after the pump, the pump when running will help to "drag" the water around the hot water circuit, but the hot water circuit will still function without the pump running

Pipe sizes and expansion tank to be decided on boiler out-put, and rad requirements when known, a powered close motorised valve could also be fitted to the heat leak rad return to allow the rad to only operate when the power is off, or either an 8 or 10mm by pass could be fitted to restrict the flow of water when the power is on