Had a biggish rennovation project done that involved replacing an old
(Potterton Netaheat) boiler with a new Vaillant Ecomax Pro boiler - 2
months ago. Incidentally, I have what I understand to be an
open-vented "S" plan system with two motorised valves. I retained the
original 2 channel programmer. The plumber (from Eastern Europe and
Corgi registered) who installed the boiler (on sub-contract from the
builder) never inspired me with much confidence. Maybe it's because
of recent stories about one-legged Romanian roofers :-).
Anyway, there's been a series of problems ever since. The boiler is
understood to be 100% OK - as confirmed by the Vaillant engineeer who
has visied twice.
The symptoms are:-
1. Recently, the circulating pump (adjacent to the HW cylinder)
appears to be running continuously - even when the programmmer is not
calling for heat. It is set to operate to provide central heating and
hot water during two time periods per day.
The radiators warm up and cool down exactly in accordance with the
programmer schedule. The boiler fires up every 3 or 4 minutes and when
the boier display reaches 68 degrees it stops heating. The temperature
in the display drops slowly to around 45 and then the burner starts up
again. This cycle carries on 24/7 - even when the programmer is not in
an active period. Presumably it is trying to heat the HW cylinder as
the radiators stay cold when the programmmer is not in an active
period. This problem has emerged only recently.
2.If I over-ride the programmer during an active period ie to shut off
the heat, then the boiler stops OK but will not restart later on
theschedule. It registers an "overheat" situation and has to be reset
by taking off two cover plates and pressing the reset button. I
believe this is because the pump stops and hence the circulations
stops - causing the combustion chamber to trigger an over-heat
After the boiler was first installed, there was no display on the
boiler when the programmer was inactive. I complained about this and
the builder brought in an electrician who connected a permanent mains
supply to give a fulltime display. We thought we were over all the
problems the problems then but a few weeks later problem 1. above
The questions that spring to mind are:-
1. Have I recently developed a a stuck motorised valve?
2. Did the plumber wire up the programmer correctly to the boiler?
3. What can I do to isolate/identify the problem further?
4. Where can I get a competent boiler installer cum plumber in South
London that can check this out.