In the area where the pump is I've now removed all the housing so I acn see
what's going on.

The pump impeller shaft is definitely turning, but I have no way of knowing
whether the impeller has come off the shaft. So, that's a possibility.

I have a pair of pipes labelled bf and br - boiler feed and return. the bf
pipe has the pump on it.

The boiler feed pipe leads down to a 3 way valve. Honeywell VC4013-02. One
arm leads off to the hot water cylinder. That pipe is hot. The other arm
goes to the central heating flow pipe. That side is all coldish. So, I'm
coming to the conclusion it's actually the motorised valve that's not
working correctly.

I took the actuator off, and there's a spring loaded piston on the hydronic
part which I can't move. I'm not sure how stiff this is meant to be? This
part of the system is all in 28mm pipework, so it's a really chunky valve
and I'm not clear how easy it ought to be to move the piston?

In case it's any help, I found a spec sheet for the valves he
http://www.honeywell.be/DocsAdobePDF...13-6013_ps.pdf



--
Murphy's ultimate law is that if something that could go wrong doesn't, it
turns out that it would have been better if it had gone wrong.

In message , GB
writes
In the area where the pump is I've now removed all the housing so I acn see
what's going on.

The pump impeller shaft is definitely turning, but I have no way of knowing
whether the impeller has come off the shaft. So, that's a possibility.


The pump is turning - you have a call for central heating

The shaft is rotating, but you seem to have no circulation

go figure

--
geoff

GB wrote:


I took the actuator off, and there's a spring loaded piston on the
hydronic part which I can't move. I'm not sure how stiff this is
meant to be? This part of the system is all in 28mm pipework, so it's
a really chunky valve and I'm not clear how easy it ought to be to
move the piston?

In frustration, I gave the piston a few taps with a hammer. On the third
tap, it suddenly sprang upwards, and we now have central heating again! (As
it was stuck fully down, that explains why no amount of pushing would get it
to go down further.)

So, the next question is whether the valve needs replacing? A bit of WD40,
maybe? In short, what do I need to do to stop this repeating, please?

Thanks for all your help.

In message , GB
writes
In the area where the pump is I've now removed all the housing so I acn see
what's going on.

The pump impeller shaft is definitely turning, but I have no way of knowing
whether the impeller has come off the shaft. So, that's a possibility.

I have a pair of pipes labelled bf and br - boiler feed and return. the bf
pipe has the pump on it.

The boiler feed pipe leads down to a 3 way valve. Honeywell VC4013-02. One
arm leads off to the hot water cylinder. That pipe is hot. The other arm
goes to the central heating flow pipe. That side is all coldish. So, I'm
coming to the conclusion it's actually the motorised valve that's not
working correctly.

I took the actuator off, and there's a spring loaded piston on the hydronic
part which I can't move. I'm not sure how stiff this is meant to be? This
part of the system is all in 28mm pipework, so it's a really chunky valve
and I'm not clear how easy it ought to be to move the piston?

In case it's any help, I found a spec sheet for the valves he
http://www.honeywell.be/DocsAdobePDF...ear/VC4013-601
3_ps.pdf




There's lots of info in the DIY-FAQ


--
geoff

On Jan 28, 10:54*pm, "GB" wrote:
GB wrote:

I took the actuator off, and there's a spring loaded piston on the
hydronic part which I can't move. I'm not sure how stiff this is
meant to be? This part of the system is all in 28mm pipework, so it's
a really chunky valve and I'm not clear how easy it ought to be to
move the piston?

In frustration, I gave the piston a few taps with a hammer. On the third
tap, it suddenly sprang upwards, and we now have central heating again! (As
it was stuck fully down, that explains why no amount of pushing would get it
to go down further.)

So, the next question is whether the valve needs replacing? A bit of WD40,
maybe? In short, what do I need to do to stop this repeating, please?

Thanks for all your help.

Give it a dose of ptfe spray and see what happens. If it jams up again
you can decide whether to keep freeing it or pay out for a new valve.
Finding the problem took the time.
BTW, you can hear if a pump is running by pressing a big screwdriver
tip to the pump and the handle to your ear.

On 29/01/2011 09:26, harry wrote:
On Jan 28, 10:54 pm, wrote:
GB wrote:

I took the actuator off, and there's a spring loaded piston on the
hydronic part which I can't move. I'm not sure how stiff this is
meant to be? This part of the system is all in 28mm pipework, so it's
a really chunky valve and I'm not clear how easy it ought to be to
move the piston?

In frustration, I gave the piston a few taps with a hammer. On the third
tap, it suddenly sprang upwards, and we now have central heating again! (As
it was stuck fully down, that explains why no amount of pushing would get it
to go down further.)

So, the next question is whether the valve needs replacing? A bit of WD40,
maybe? In short, what do I need to do to stop this repeating, please?

Thanks for all your help.

Give it a dose of ptfe spray and see what happens. If it jams up again
you can decide whether to keep freeing it or pay out for a new valve.
Finding the problem took the time.
BTW, you can hear if a pump is running by pressing a big screwdriver
tip to the pump and the handle to your ear.

"The pump impeller shaft is definitely turning, but I have no way of
knowing whether the impeller has come off the shaft. "

Andy