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MaidenheadChris

Hi there - can anyone make a recommendation as to whether I should go with a Worcester Bosch or Baxi system boiler when installing a Megaflo hot water cylinder? This is a full house renovation and the owner wants to use an iBoost (from their new solar PV) with the tank.

Any experiences (good or bad) with either? Let me know!!!
 
Any experiences (good or bad) with either? Let me know!!!

In my own home I have a recently-installed Worcester system boiler and Megaflo Eco cylinder (no PVs) in an S-plan+ setup. There's one issue that may only be obvious with hindsight.

For the Megaflo to get up to the recommended 60°C so its thermostat stops demanding heat the flow temperature of the boiler needs to be set to a minimum of 65°C. This means for the boiler to be in condensing mode you need to get the temperature difference between flow and return of at least 12°C and preferably a touch more.

I live in the SW and for a good fraction of the year 65°C is a bit warm to get optimal perfomance from the CH even with conventional radiators. I imagine that UFH, which I don't have installed, would benefit from it being even lower.

Worcester does have a boiler controller ('Wave' IIRC) that allows the CH and HW temperatures to be set independently, but according to its docs it requires thst you have the optional internal divertor valve kit installed, which gives you a Y-Plan base system. This limitation is a bit frustrating as in an ideal world I'd want the hot water to heat up to 60°C in the night, say with 70°C flow and then the rest of the time have the flow temperature for the CH much lower. (I prefer S-plan to Y-plan.)

In practice the current system althought not 'theoretically ideal' is nice and simple and works well.
 
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I am a Vaillant man myself. Don't know much about solar. But I'm sure that Vaillant do a boiler that can cope with what you require. Have a look at them and see what you think.
 
the owner wants to use an iBoost (from their new solar PV) with the tank.

How do the economics of that work? I pay six or seven times as much for electricity as I do for gas. I'd have thought it makes more sense to export electricity and use the money from the generation and export tariffs to buy gas?
 

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