FAO IANMCD please.
Ian,
As someone with 70-years reputation for fixing just about anything,
including professionally to this day, it's a bitter blow that I can't
fix my own boiler, and neither so far has my plumber / heating engineer
Steve been able to, though he did do some good diagnosis, and is still
involved, but VERY busy.
My boiler was installed in 2013, and worked beautifully till about a
month ago.
Then it misbehaved and would not do the business. Even with TIMER and
STAT and MAINS all live, it wouldn't do the job.
There is no doubt the TIMER and STAT are good.
First, the Burner motor would buzz but not start. This was easily
checked for capacitor failure (which it was) and a new capacitor of the
OEM type was bought and fitted. Now the Burner motor runs again. I
bought two 4.5mFd capacitors so I have a spare.
Sometimes it was possible to make the boiler work the CH, but usually
not. The DHW was fine after the burner motor revived.
Steve correctly said the Diverter Controller was a suspect, so I got him
to fit a new one.
I checked the old one and beyond any doubt the contacts in the internal
NO microswitch are done.
It did not make a clean CLOSED contact when the DV motored from A-DHW to
B-CH.
Very poor contact was being made, which might not do any good for the
next thing along the line.
(I have since fitted an absolutely identical microswitch to the old DV
controller)
So now it has a brand new DV controller and also new DV valve itself for
good measure.
But it is still misbehaving.
The DHW works perfectly well, BUT . . . using DHW stops the CH dead.
The boiler WILL NOT switch the diverter valve back to B-CH position, and
the circulation pump does not appear to run.
I have discovered that the following procedure will get the CH going.
1. Make sure TIMER and STAT are both ON demand. This is easy.
2. Go out to boiler and lift off the front panel using the new handle I
invented.
3. Try the DV controller lever, and at this stage it always seems LOCKED
in A-DHW position.
4. Switch the control panel main switch to the lowest SERVICE position.
5. Now the DV controller is NOT LOCKED, and can be carefully moved
(once) as far left towards B-CH as it will go.
6. Now release the lever and it will smoothly return under spring
pressure to A-DHW.
7. Now switch the panel power switch back ON, and IMMEDIATELY the boiler
starts to motor the DV Controller to B-CH, the circulation pump starts,
and shortly the burner comes to life and away we go.
As long as I do not use a DHW tap, it will usually keep going all day
with the STAT set well up, say 22~24°C which the space never reaches.
Using DHW will mean no more CH until I do 1 - 7 all over again.
Usually it won't re-start the CH if the STAT stops it for a while, even
if I turn the STAT up to about 30°C!
So . . . what am I doing wrong, or what am I missing?
I'd be delighted if this fault can be identified, because then Steve can
set about and fix it.
Best Wishes,
Charles
(Just along the A71 near Newmains)
Ian,
As someone with 70-years reputation for fixing just about anything,
including professionally to this day, it's a bitter blow that I can't
fix my own boiler, and neither so far has my plumber / heating engineer
Steve been able to, though he did do some good diagnosis, and is still
involved, but VERY busy.
My boiler was installed in 2013, and worked beautifully till about a
month ago.
Then it misbehaved and would not do the business. Even with TIMER and
STAT and MAINS all live, it wouldn't do the job.
There is no doubt the TIMER and STAT are good.
First, the Burner motor would buzz but not start. This was easily
checked for capacitor failure (which it was) and a new capacitor of the
OEM type was bought and fitted. Now the Burner motor runs again. I
bought two 4.5mFd capacitors so I have a spare.
Sometimes it was possible to make the boiler work the CH, but usually
not. The DHW was fine after the burner motor revived.
Steve correctly said the Diverter Controller was a suspect, so I got him
to fit a new one.
I checked the old one and beyond any doubt the contacts in the internal
NO microswitch are done.
It did not make a clean CLOSED contact when the DV motored from A-DHW to
B-CH.
Very poor contact was being made, which might not do any good for the
next thing along the line.
(I have since fitted an absolutely identical microswitch to the old DV
controller)
So now it has a brand new DV controller and also new DV valve itself for
good measure.
But it is still misbehaving.
The DHW works perfectly well, BUT . . . using DHW stops the CH dead.
The boiler WILL NOT switch the diverter valve back to B-CH position, and
the circulation pump does not appear to run.
I have discovered that the following procedure will get the CH going.
1. Make sure TIMER and STAT are both ON demand. This is easy.
2. Go out to boiler and lift off the front panel using the new handle I
invented.
3. Try the DV controller lever, and at this stage it always seems LOCKED
in A-DHW position.
4. Switch the control panel main switch to the lowest SERVICE position.
5. Now the DV controller is NOT LOCKED, and can be carefully moved
(once) as far left towards B-CH as it will go.
6. Now release the lever and it will smoothly return under spring
pressure to A-DHW.
7. Now switch the panel power switch back ON, and IMMEDIATELY the boiler
starts to motor the DV Controller to B-CH, the circulation pump starts,
and shortly the burner comes to life and away we go.
As long as I do not use a DHW tap, it will usually keep going all day
with the STAT set well up, say 22~24°C which the space never reaches.
Using DHW will mean no more CH until I do 1 - 7 all over again.
Usually it won't re-start the CH if the STAT stops it for a while, even
if I turn the STAT up to about 30°C!
So . . . what am I doing wrong, or what am I missing?
I'd be delighted if this fault can be identified, because then Steve can
set about and fix it.
Best Wishes,
Charles
(Just along the A71 near Newmains)
