This one will put you to the test……..
I have came across an situation in a pub/restaurant where I have a combination boiler (also used like as a system boiler) linked also to a mega flow water heater ( unvented indirect cylinder) the hot water is only 65 in the morning and is look warm for the rest of the day as it does not recover in time. Even with an immersion heater on allday.
(this has never worked correctly from day one and was only installed 3years ago by some plumber who doesn’t to his sums rite)

I want to work with what iv got to improve the hot water situation as.
The combi dhw side only feeds one outlet close by and can’t be used to feed the rest of the outlets as there is simply just to much of a demand.
The one outlet it feeds the one outlet never used
There is not enough room for a secondary return to the cylinder
The boiler and the cylinder are in a small store room

Basically I’m in need of a great engineering idea!

I do have an idea but have never seen or attempted to do it before…
Can I??? take the dhw from the combi to feed the inlet of the cylinder, then take a pipe(return) from hot distribution back to the cold inlet of the combi creating a circuit (I would also fit a bronze pump…pumping the hot back to the cold inlet of the combi) I think it may work but unsure whether the combi would fire up when there is no hot taps being used… hence the reason why I have the idea of adding a pump to the circuit to make the boiler think there is a outlet open.

Ryan mm, April 2009

have i got it right that the mega flo is only heated by the immersion heater. if this is the case then i would just find out why this isnt heating the water correctly. they are designed to heat the whole tank so is most prob a thermostat proble on the immersion or the element itself.

gg, April 2009