UK One way 240v flow HOW

[Vaf888]

Good Morning.

I have a fused spur which has 2x240v inputs and 1x240v out put.

The 240v inputs are from heating control panels. One is from a timer clock for hot water and the other from a large 1000l hoh water storage tank. The ouput is to the oil burner.

So the question is when i have i have a single input switched on with other input off the off input is getting a live feed, from the on input. Is there anything that can be wired in to make the flow one way only.

Thanks

 

[Bellendian]

Hi,

A schematic of the hydraulic side of the system would be handy. If I'm reading this properly, you have 2 tanks? At large thermal store controlled by the Resol Controller, which is used for Central Heating? And a Smaller DHW cylinder for the Hot Water?

 

[Vaf888]

Yes. Thats it. Only the two zones on the xl27 clock are connected to two hot water cylinders, and when the cirucuit is on a pump on the hot water line activates to draw the hot from the main feed connected to storage tank.

I am not the original owner of the house, but came across these drawings for the hot water.

Thanks
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Two values for the two tanks with the hot water pump connected below.

 

[Bellendian]

Hi,

Thanks for info. Only had a quick skim read, but it looks like the boiler fire signal should only be supplied from the Resol controller. That will control the temperature in the buffer tank and tell the boiler when it needs heat.
The zone valves for the hot water cylinders simply need to open, and when open activate the pump to circulate from the buffer tank, no connection to the boiler should be needed. As the heat is drawn out of the buffer tank, the resol controller will detect the temp drop, call for heat, and fire the boiler.
I think that is how it should be set up?

 

[Vaf888]

Yeap i agree and that works, but does that mean the boiler pump always needs to be on. I have noticed that if the repol is calling for heat, the boiler fires along with its pump, and if the hot water is on its all good. But if the repol is off the boiler along with its pump is off. Hot water kicks in and the hot water pump starts. Because the boiler pump is off there doesnt seem to be a flow.

Obvious then when the CH is off during the summer i would turn the Repol off and close of the inlet and outlet to the storage tank and then switch to a direct feed via the insolation switch.

Question do pumps internals lock with no power and would a temp set of 50 degrees to the hot store be enough to heat the water. If i jump to the summer scenerio the temp from the boiler would be 70 plus.

Thanks

 

[Mike Johnson]

Have you checked the synchronous valves are working, it sounds like a flow problem from one of them?

 

[Vaf888]

Hi Mike. Yes both pumps work.

Thanks
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Ideally for the HW both pumps, and for the CH just thr boiler pump. If i can sort the bavk feed problem it would me that can have the direct HW direct to the boiler via the junctioned spur. So when the HW clock kicks both pumps are on. If the HW is off and the CH is on, the live feed from the CH is turning the HW on via the back feed. Thats why have the manual switch in there at the moment.

Cheers

 

[Bellendian]

Are the hot water cylinders unvented?

 

[Vaf888]

Not sure. How can i tell
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There is a large red cylinder connected on the main return of the boiler of that hrlp
[automerge]1585080934[/automerge]
There is a large red cylinder connected on the main return of the boiler of that hrlp

 

[Mike Johnson]

Not the pumps, but the valves, they have a an electric motor inside them that opens and close's the valve's if one of those has gone open circuit the flow will not happen.

View: https://youtu.be/KT6mq1440zM

 

[Vaf888]

Hi Mike. All the motorised values are working.

I need a solution to thw back feed. Looking at 25amp no nc contractor with a coil. Would this work to stop the back feed?

Thanks
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I dont so many connections as the HW on has two wires.

Look electrical supplier suggested this, but not sure.

 

[Bellendian]

Need to be careful here. If cylinders are unvented, and you are trying to alter the controls, then this can have disasterous consequences.
I would recommend you get a professional to look at the system first hand. For what it's worth, I don't see the issue with leaving the resol controller on in the summer, these buffer tanks are normally very well insulated, and without altering pipework, chances are you're trying to draw boiler flow water through the buffer direct to cylinders without mixing, which is unlikely to work. With some pipework mods, a safe and operable system could be made to bypass buffer for a winter and summer mode, but I wouldn't suggest it's a DIY job.

 

[Vaf888]

The only thing i have changed on this is the heat source. Which was a wood pellet burnsr. It was wired with two. Zero volts inputs CH and HW. Now that i have changed the heat source to oil, the new burner only has a single 240v input.

I did not think the change of the heat source would have any impact on the actual plumbing side of things, just the electrical side due to the single input. Am i being stupid here.

Do you know about the contractor?

Thanks

 

[Vaf888]

Thanks for all your help guys. After a bit of research, it turned out the original contactor which was in the system was wired incorrectly by the installer so not activating the coil.