S-plan cylinder connections

[M1957]

I have what appears to be an S plan system, but the hot water cylinder connections are slightly different to a typical setup. It's an old system so I wondered if there might be a reason for these differences.

The image below shows the valve assembly. The pump output comes vertically down (red arrow), and then there are two motorised valves. The top one is for the cylinder coil and the one near the floor is to the radiators.

The upper two horizontal pipes are for the cylinder coil. The one near the floor is the return (for the whole system)

The cylinder coil seems to be in "parallel" with the boiler flow, causing slow hot water. Is there a reason why it might be installed like this?

Thanks in advance

 

[Mottie]

The image below

No image.

 

[M1957]

No image.

Apologies, is it visible now?

 

[Hugh Jaleak]

I can see the pic, but not sure quite whats going on, can you do another shot of the cylinder and connections please? You seem to have 1 too many pipes for a normal setup, middle pipe with the gate valves fitted, one looks to be a bypass, not sure where the other is going?

 

[M1957]

I can see the pic, but not sure quite whats going on, can you do another shot of the cylinder and connections please? You seem to have 1 too many pipes for a normal setup, middle pipe with the gate valves fitted, one looks to be a bypass, not sure where the other is going?

The horizontal gate valve is to the lower cylinder coil output.

The pipe along the floorboard is the return. Where it comes out the floor at the bottom of image is the return from the radiators. It then flows along the floor and goes back to the boiler.

I'll try to upload a better picture.

 

[Hugh Jaleak]

Cylinder coils have a flow and return connection, (unless you've a twin coil cylinder, but then you'd be looking at a second heat source), hence my confusion on where the third pipe goes. Where does the pipe circled lead to?

 

[M1957]

Cylinder coils have a flow and return connection, (unless you've a twin coil cylinder, but then you'd be looking at a second heat source), hence my confusion on where the third pipe goes. Where does the pipe circled lead to?
View attachment 216141

It's the cylinder return. The one above it with the valve is the flow.

The red arrow shows the main flow from the pump.

 

[Hugh Jaleak]

It cannot be the return as it is connected to the flow!

 

[M1957]

It cannot be the return as it is connected to the flow!

That's the way it has been installed - the cylinder flow and return are connected to the same pipe from the pump output.

I've annotated a slightly better image to explain what's going on.

Note the small pipe with the push fit is for a towel rail, not the cylinder.

 

[denso13]

the cylinder flow and return are connected to the same pipe from the pump output

If that is the case then it is wrong.

 

[ianmcd]

Do you have a seperate thermostat for upstairs and downstairs, I think you have got mixed up on what is the return

 

[M1957]

Do you have a seperate thermostat for upstairs and downstairs, I think you have got mixed up on what is the return

There is only one thermostat. The main return is definitely the 28 mm pipe along the floorboard. It comes out the floor next to the heating valve from the radiator circuit and then flows towards the back of the cupboard and round back to the boiler.

There seems to be a bypass valve which has to be slightly open otherwise the pump is dead headed if only the hot water is on.

 

[ianmcd]

yes one of those gate valves is a by-pass, but havent a clue what the other one is, unless possibly a manually way of isolating a zone on your system

 

[M1957]

yes one of those gate valves is a by-pass, but havent a clue what the other one is, unless possibly a manually way of isolating a zone on your system

It's a gate valve on the cylinder return but it probably doesn't do very much. The cylinder has been installed a bit like a single pipe radiator meaning it is slow to heat up. I think the previous posts are correct that it's a faulty installation.

Thanks for helping, I will get it looked at soon.

 

[JimCrow]

Cap off that gate valve and bin it, cut in another tee on the return after the last radiator tee on the system, the nearest to the boiler.

You could also replace the vertical gate valve with an auto by-pass valve whilst you have it drained.