Learn what you can do to help your systems run smoothly and reliably! James foy plumbing ltd, plumbers, liverpool. Replacing a regular boiler and hot water cylinder with a combi boiler. The fire tube design of the heat exchanger provides a greater efficiency and a lower pressure drop the built in stainless steel indirect storage tank provides endless hot water and eliminates temperature fluctuation! Country of origin: united states. Is a plumber required to be insured and bonded?.