In an earlier contribution to this discussion,
Neil DG wrote:
Roger
Does the oil-fired boiler normally heat the HW in addition to the
CH? If so, is this part working - heating the water to the correct
temperature without getting too hot?
Yes I have hot water but not as hot as usual.
There are two valves - Honeywell V4043H1056.
How can I test if it is a broken return spring in the actuator ? You
say simply but does not sound simple to a man of my knowledge !
Is your advice to remove the actuator and try to turn the valve - not
that I actailly know how to do that but am prepared to give it a go if
you say its easy.
Thanks for your response
Neil
There are 3 basic things which could be wrong with the valve and /or
actuator - so you need to test for each in turn.
1. The valve could be opening and closing ok, but its secondary contacts
could be welded together - switching the boiler permanently on. This is the
least likely, so we'll eliminate that first.
See
http://content.honeywell.com/uk/home...19%20V4043.pdf
for a picture of the valve. When the valve is closed (which it should be
when the heating is supposed to be off) the lever will be in the position
shown. You should be able to move it to the other end, to open the valve
manually. You will only be able to move it slowly, and will hear the
internal gears whirring as you do so. If the lever moves freely to the end
without resistance or whirring, and just flops about, this indicates that
the valve is remaining open. If the valve *can* be opened with the lever,
and closes again when you let go of the lever, then it is the contacts which
are faulty - but I don't think this is the case, because it doen't really
fit your symptoms.
2. Assuming that the valve *is* staying open, it can be for either of two
reasons. Either the mechanical 'wet' part of the valve is seized, or the
return spring in the actuator has failed. To find out which, you need to
remove the actuator from the valve. I'm not totally sure how this comes off
(mine's a Danfoss!) but there are probably 2 screws going upwards through
the baseplate into the bottom of the actuator. Remove the screws and lift
the actuator off the valve proper. If the return spring is ok, the actuator
will immediately return to the 'valve closed' position - in which case the
lever should then operate in the proper fashion. If the actuator doesn't
move when it's no longer constrained by the valve, the fault is in the
actuator - probably the return spring. In this case, you'll need to get a
new actuator.
3. Assuming the actuator is ok, look carefully at the valve now that the
actuator is removed. There is a round shaft with a flat on it - making it
like a D in cross-section. It is this shaft which is rotated by the actuator
to open and close the valve. You should be able to rotate the shaft through
90 degrees with finger and thumb - or, at any rate, using *light* pressure
with a pair of pliers. If it's too stiff to move, that's your problem! Use a
bit more pressure with your pliers, and try to rotate it backwards and
forwards. [If you observe the D-shaped hole in the bottom of the actuator,
when you operate the lever manually, you'll see in which direction the shaft
needs to point in the open and closed positions]. With a bit of luck, you'll
manage to free it up such that when you fix the actuator back on, it will
open and close properly. If not, the wet part part of the valve will need to
be replaced which - from what you say - probably means that you'll want to
find a plumber rather than DIY-ing it.
--
Cheers,
Roger
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