Which indirect unvented cylinder

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Hi all this is a follow on thread from a post regarding new combi or invented cylinder.
I have decided on an unvented cylinder and keeping the existing boiler.

I’d like to have the option of solar in the future. This would either be by PV (not sure I’ll have the roof space) or thermal. I’m tempted to get a solar cylinder (with secondary coil) as I have the option to add if that’s what I want to do.

I’m looking at 300 litres as of adding solar in the future it will make the most sense.

I’m looking at an OSO delta twin coil or a megaflo solar.

OSO are not making the twin coil anymore due to lack of demand. This cylinder is not their A rated one. Think it might be C.

The megaflo has an internal baffle which I’ve heard needs recharging regularly. Also a C rated boiler. Might not make much difference overall.

Any other recommendations. Albion, Joule?

I might be over thinking this but want to get it right first time.

Thanks
 
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I had a chat to OSO and the guy said both Megaflo and OSO are very good (refreshing to hear that).
He recommended a supercoil 250 as it has an integral mixing valve so the volume of 40 degree hot water is 355 litres (tank heats to 60 degrees).
It's a C rated cylinder but keeps everything neat as components built in with the exxpansion vessels under a lid.
Anyone have experience of the supercoil?
 
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If you are talking about a 250L cylinder at 60C then you should get over 390L at 40C from cold water at 5C
 
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If you are talking about a 250L cylinder at 60C then you should get over 390L at 40C from cold water at 5C
Yeah it didn’t make sense what the guy way saying. I said you’d mix at point of use anyway. He suggested that you get more when mixed at source. Does that make sense?
 
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No, not to me anyway, also getting 355L at 40C from 250L at 60C means thermodynamically that the (very) cold water is at minus 7C!. I would just ensure that the cylinder is actually 250 Litres.
 
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No, not to me anyway, also getting 355L at 40C from 250L at 60C means thermodynamically that the (very) cold water is at minus 7C!. I would just ensure that the cylinder is actually 250 Litres.

So I looked at the literature just now (tried to share a screenshot but the file is too big apparently).
The 250l is actually 239l in that model. They quote a V40 L of 355l. Not sure where the value comes from. The recovery time is 34 mins and hear you time is 48 mins.
Heat loss is 1.92 kWh/day.
I’ll chat to my plumber and see what he says. Might be back to a megaflo
 
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So I looked at the literature just now (tried to share a screenshot but the file is too big apparently).
The 250l is actually 239l in that model. They quote a V40 L of 355l. Not sure where the value comes from. The recovery time is 34 mins and hear you time is 48 mins.
Heat loss is 1.92 kWh/day.
I’ll chat to my plumber and see what he says. Might be back to a megaflo
That's not correct either, I think they are just dividing 60/40 and X by 239, correct calc would mean that the cold water would have to be minus 1.2C to give 355L @40c from 239L @ 60C. However what you will certainly get from that 239L cyl @ 60C is.....375L @ 40C from C.water @5C, 398L @ 40C from C.water @10C, & 430L @ 40C from C.water @15C. Install a 300L cylinder and the corresponding numbers are 471L @ 40C from C.water @5C, 500L @ 40C from C.water @10C, & 540L @ 40C from C.water @15C.

It looks like a ~ 20kw heating coil is installed.
 

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