DIYbanter - View Single Post - Don't understand why our boiler keeps firing up within a Megaflow heating system

wrote:

Looking for advice he

We have just moved into a new house (7 years old) where we have two
boilers connected to a heating and hot water system. We have two
thermostats on each floor and a electronic timer to start and stop the
system of hot water and heating. In our airing cupboard we have two
Megaflow tanks which I guess contain the hot water.

What we cannot understand is why when we swith off all the heating an
hot water our boilers (well one of them) fires up perhaps every 15 mins
for 25-30 seconds and then turns off - even when we think we have
turned everyting off - also it looks like we have continuous hot water
which seems wasteful of energy. I guess the megaflows provide us with
the good pressure we enjoy and hence I understand why they also
continually hiss as it seems they are on.

Looking for anyone who can shed light to our potential misunderstanding
on how our configuration works. Note as of yet we have never seen the
second boiler light up, even when we turn on the heating and
thermostats

If you have a Megaflow (or even two!) you should have it serviced annually
by a qualified (for unvented heating systems) engineer to ensure that the
safety systems are still working properly. Sounds as if you could do with a
visit from someone clued up to check out your system. By all means get
clued up yourself to find out what's going on, but unvented systems carry a
risk - very very remote, but if it happens very very severe - of a steam
explosion if things go wrong, so do get it checked out professionally. If
you can afford a house with 2 boilers and 2 Megaflos, you can afford to
have it serviced!