Any way to bypass the water cyclinder in a vented system?

Galego · 25-06-2022 08:52AM #1

At the moment I can have/control the boiler heating the hot water in the cycling without heating the water in the radiators. But when it is heating the water in the radiators, it is also heating the water in the hot water cyclinder.

Any way to bypass the cyclinder and have the boiler exclusively heating the water in the radiators?

I would guess it should save the boulder having to heat 180ltr tank when heating radiators.

Ubbquittious · 25-06-2022 10:52AM

If you have a valve on the coil of the cylinder you could do it. I have such a system & controller to operate that valve so it can run the cylinder for a certain time then switch to rads.

but if there is a solid fuel stove then it's a bad idea to do this

John.G · 25-06-2022 11:10AM

https://www.boards.ie/discussion/2058251690/any-way-to-bypass-the-water-cyclinder-in-a-vented-system

Have you got a timer with two zones one may be labeled HW?, you should also have either a 3 way motorized mid position valve or two separate 2 way motorized valves, (both shown below), have a look around.

Galego · 25-06-2022 11:23AM

Yes I have one of those motorised valve which allows me to do hot water only.

But when heating is on also heats the cyclinder.

I see the below valve next to the cyclinder. Would I need to replace this one for a motorised one so I can isolate the heating and skip the cyclinder?

John.G · 25-06-2022 11:27AM

Which type of motorized valve is installed, a 2 way or a 3 way and have you got a timer/programmer? (can't see the valve in your photo, above).

I can see the red gate valve so yes that should be replaced with a 2 way motorized valve but it will need wiring to a timer, that's why I asked what type of timer you have installed, if any.

Galego · 25-06-2022 11:36AM

https://www.boards.ie/discussion/comment/119247768#Comment_119247768

Just posted the photo. Two zones.

John.G · 25-06-2022 12:05PM

Two zones can mean that you have one zone valve serving the downstairs rads and the other serving the upstairs rads or you may have one zone valve serving both upstairs and downstairs and the other zone serving the HW cylinder, is the M.valve shown or the other one installed on the any one of the HW cylinder pipes (coil) either the flow or the return.

Can you post a photo of the timer.

Galego · 25-06-2022 12:31PM

The motorised valve is installed downstairs to the pipe which goes up to the he cyclinder so I believe one zone serves all radiators and the other one the hot water cyclinder. But I am sure when the boiler is heating the water for all radiators it is also heating the water in the cyclinder. Does it make sense?

The timer is one of these new fancy ones (Tado) with an app where I can select heating or hot water.

John.G · 25-06-2022 01:11PM

Yes, that makes sense. Ensure both systems off and then select rads only on while watching or listening to see if the HW M.valve also opens.

Galego · 25-06-2022 01:55PM

https://www.boards.ie/discussion/comment/119248140#Comment_119248140

I'll do that whenever I get home but I have the feeling that when I switch the heating on the hw m.valve also opens. Very confident that does that.

If that was the case.......has it been set up by the plumber to do that? And could I change that setting so remains closed when I switch the heating?

John.G · 25-06-2022 02:03PM

Not familiar with the Tado system but will read up on it, best talk to the plumber as he would certainly would not set it up intentionally to operate as above.

Galego · 25-06-2022 02:27PM

https://www.boards.ie/discussion/comment/119248299#Comment_119248299

It was installed almost 10 years ago......only now it is bothering why it heats cyclinder too as the price of heating oil has gone off the roof.

This is a photo of the thermostat and how it is meant to be wired. Does the below makes sense so the hw m.valve doesn't open when switching the heat?

Screenshot_2022-06-25-15-28-51-001_cn.wps.moffice_eng.jpg

John.G · 25-06-2022 04:48PM

That looks typical S plan wiring to me except that it doesn't show a CH roomstat but that (they) might be wireless stats that are controlled by the TADO and as long as any one is looking for room heat then the CH wireless relay is closed to open the motorised valve via its brown&blue wires, a internal (end) switch in the M.valve then switches on the boiler via the permanently live grey wire and the (now switched) orange wire. The HW works similarly except that the M.valve is energised via the cylinder stat. I don't see any reason for the HW to come on with the CH. Try switching in the CH only then turn down the cylinder stat until you hear a click (or turn it right down) and check that the HW M.valve closes.

wiz569 · 25-06-2022 05:06PM

If there is only one 2-way valve then its working as intended surely, you would need another 2-way or else one 3-way instead no?

Galego · 25-06-2022 05:08PM

https://www.boards.ie/discussion/comment/119248913#Comment_119248913

Is it possible that I don't have a cyclinder stat? I can't see any around the cylinder.

John.G · 25-06-2022 05:20PM

https://www.boards.ie/discussion/comment/119248981#Comment_119248981

Post 8 says 2.

https://www.boards.ie/discussion/comment/119248990#Comment_119248990

It would be most unusual, there may be a sensor inserted in a dry cylinder pocket, if so, you should see a wire coming out somewhere ~ 18" up from the cylinder bottom. You may have both room stat and cylinder stat settings in your App or whatever its called. If so do as I asked above and then turn down the cylinder stat setting to say 30C and see if the M.valve closes. (CH only ON)

Galego · 25-06-2022 06:13PM

https://www.boards.ie/discussion/comment/119249034#Comment_119249034

100% no thermostat in the cyclinder. I checked everywhere and no wires anywhere or any stat.

I guess there is a stat at the boiler with the water temperature for that cylinder?

wiz569 · 25-06-2022 06:19PM

https://www.boards.ie/discussion/comment/119249034#Comment_119249034

Post 8 only says "the" motorised valve that I can see John? And the pic in post 6 is a 2-way no?

John.G · 25-06-2022 06:22PM

Looks that way all right, still doesn't solve your problem though, have you any photo of the actual wiring center close up and we might spot something there.

John.G · 25-06-2022 06:30PM

https://www.boards.ie/discussion/comment/119249305#Comment_119249305

Post no 6 says "Just posted the photo. Two zones." so 2 X 2way valves??, also Galego says he can have HW only (no rads) but not Rads only (no HW)

Post no 8 also states "The motorised valve is installed downstairs to the pipe which goes up to the he cyclinder so I believe one zone serves all radiators and the other one the hot water cyclinder."

But whole set up a bit confusing.

John.G · 25-06-2022 06:33PM

Can you post a photo of the two M.valves please.

wiz569 · 25-06-2022 06:37PM

https://www.boards.ie/discussion/comment/119249368#Comment_119249368

I have a feeling that the OP may think that a 2-way valve creates two zones, whereas its actually just a motorised gate valve, definitely need more info and pics.

Gant21 · 25-06-2022 06:44PM

The op has the paddy spec plumbing installation. Hw on its own or hw and ch.

John.G · 25-06-2022 06:46PM

Maybe his one does 😁😁

Galego · 25-06-2022 06:55PM

Here you go.

John.G · 25-06-2022 07:25PM

Wiring doesn't tell me much, switched live label looks like suitable for a 3 way valve.

Gant21 · 25-06-2022 07:35PM

https://www.boards.ie/discussion/comment/119249622#Comment_119249622

The threesome I don’t think so ops clock has two outputs. As you previously mentioned we need to see all valve(s).

Galego · 25-06-2022 07:53PM

I am only able to find one motorised valve. To me looks like a zone 2 type. See photo below. There is a manual valve nearby.

ongarite · 25-06-2022 08:06PM

Tado only supports 2 zones so from your description it's setup for heating only & water+heating?

Do you have 3 zones, downstairs heat, upstairs heat & water with motorised valve for each?

Really useful discussion on smart home heating. Some Tado users on there who can help

https://www.boards.ie/discussion/2057758281/home-heating-automation

John.G · 25-06-2022 10:33PM

If only one zone valve then still a mystery to me, if this zone valve is supplying the CH and the HW cyl coil then both must be teed off after (downstream of) the M.valve so how can the HW cyl coil only be supplied with the M.valve shut and boiler only firing, if the HW cyl coil is supplied upstream of the M.valve then it does work in the fashion it is? so post 23 correct.

Galego · 27-06-2022 10:35AM

https://www.boards.ie/discussion/comment/119250396#Comment_119250396

Yes it seems that way. Hw on its own or hw and ch.

A gravity hot water system.

Is there anything which I could do in order to separate the ch from the hw?

Any way to bypass the water cyclinder in a vented system?

Comments