Decommissioning vented cylinder heated by Danesmoor oil boiler

[northwalesDIYer]

Hi there

Struggling to get any sense out of local plumber so looking for advice.

My current heating system comprises a Worcester Danesmoor oil boiler heating a vented hot water cylinder and powering the radiators. This controlled via an S-plan wiring system.

Due to poor hot water pressure I would like to replace the vented cylinder with a direct unvented cylinder. This will be a direct cylinder because I am moving it to a different part of the house, it will be some way from boiler, and I would prefer to heat it cheap off peak electricity than heating oil.

Plumber will be fitting unvented cylinder and is G3 accredited.

My question is around decomissioning the existing vented cylinder which the plumber seems unsure about, specifically the flow / return pipes from the oil boiler. Can these be simply "joined together" at the location of the existing cylinder creating a redundant closed loop? The boiler will be operated in central heating mode only. Can I retain the S-plan wiring system, albeit the DHW element will be redundant or do I need to look at simplifying? The cold water heater tank in the loft will be removed and the feed pipe capped.

Cheers

 

[Agile]

A much cheaper solution would be to fit a shower pump.

Are you very sure that you will be able to continue to get cheap off peak electricity?

Any unvented needs a very good dynamic mains flow rate. Many installers struggle to understand the needs. An open pipe flow rate is almost irrelevant.

Your other ideas seem to be OK.

 

[stem]

If you are moving the cylinder some distance away from where it is now; will that also be extending the distance from the cylinder to the points of use? It can be very irritating, as well as wasteful, waiting for a prolonged period of time for some hot water to arrive. On the other hand, if by moving the cylinder, you are shortening the distance to the points of use that's a distinct advantage.

 

[northwalesDIYer]

Thanks for suggestions.

Shower pump has been considered but I do not want to go down this route, even if it is a cheaper option. Not a fan of the noise. I should have added that removing the existing vented cylinder frees up some much needed space in a cupboard and would allow me to fit an en-suite in the future.

In terms of cheap off peak electricity, we also have solar panels which we can use to heat the tank for free using excess generation.

By moving the cylinder I will be shortening the distance to the points of use (marginally) which is a bonusThe installer has tested dynamic pressure and flow (4 bar and 25L a minute at the outside tap).

The installer has tested dynamic pressure and flow (4 bar and 25L a minute at the outside tap) which on my understanding should be sufficient. The outside tap is fed via 15mm pipe, so potential to improve on this by taking a direct 22 mm feed from the cold supply to the unvented cylinder.

 

[Exedon]

Is your heating system sealed system or tank feed?
If your 'plumber' don't know how to disconnect and deal with the cylinder flow and return from a boiler I would have serious doubts about there capabilities.

 

[rikdogguk]

@Exedon the hot water vented cylinder therefore unsealed and fed by a header tank in the loft. The central heating is also vented with an f&e tank in loft. I would be retaining the unvented central heating system. How would you propose to deal with decommissioning the vented cylinder flow and return?

 

[rikdogguk]

@Exedon I don’t disagree with your assessment of plumbers skills but there are very few plumbers in my area and even fewer with G3 cert and willingness to quote. So I’m trying to work with what I’ve got!

 

[Exedon]

Unfortunately there are several possible ways your existing may be piped up.
Where is your pump and motorised valves ?
How is heating cold feed and open vent connected?
Put some clear pictures up

 

[ChrisJP]

Joining the feed & return pipes from the boiler to the coil in your existing hot water cylinder, and doing so at the old location of the cylinder would certainly work as a workaround. But water will still circulate around this loop, losing heat in the process, whenever the boiler is on. You really need to disconnect and cap the pipes feeding this loop at their origin point.