Installation of System boiler above unvented cylinder

[Phill Peck]

Thanks. Is the advantage of the 4 pipe that there's less components and it can switch easily between the modulation for CH and quicker DHW heat?

On a 4 pipe system it has internal diverted with hw priority.
one I did recently was 30kw boiler 250ltr unvented. Heated the whole tank from cold to 60 in 15 mins. The boiler will recognise the drop in cyl temp and fire full rate.
This customer has 4 daughters and his wife. Couldn't remember the last time he had a hot shower. He considers is life changing not running out of hot water.
#firstworldproblems

 

[andyman22]

Thanks. I'm kind of getting the impression that only my plumber wants me to get a 222...

 

[muggles]

If your installer wants you to have a 222, maybe you want a different installer?

 

[andyman22]

Think you're right!

 

[Phill Peck]

20ltrs a min is adequate for your average house but.
The 4pipe boiler and cylinder offers more for less.
Looking into the future I would say seperate boiler/cyl will be cheaper to maintain. And more reliable

 

[andyman22]

Thanks for everyone's help.