Is there such a thing? If so, does anyone have one they know to have run
trouble free for say 3 years: if so what make is it?

Our current one is a Honeywell, and is very rickety inside. I recently had
to look at the micro-switches and even found that one of them had even been
assembled with the contacts twisted! Even after straightening the contacts
getting the thing to balance properly again was very fiddly, as all the
springs and cams and the like are thin and wobbly, and it even changes as
the mounting screws are tightened. Thus it is now stuck in the mid position
again. This is the third actuator we have had. The first was a Potterton
and quite sturdily made, but its backing plate was brittle and broke when I
went to replace the contacts. The replacement newer Potterton only lasted
about a year, before needing new contacts. Next time I went for the
Honeywell, which has, as above proven to be expensive rubbish.

Are there any good ones out there?

S

"spamlet" wrote in message
...
Is there such a thing? If so, does anyone have one they know to have run
trouble free for say 3 years: if so what make is it?

Our current one is a Honeywell, and is very rickety inside. I recently
had to look at the micro-switches and even found that one of them had even
been assembled with the contacts twisted! Even after straightening the
contacts getting the thing to balance properly again was very fiddly, as
all the springs and cams and the like are thin and wobbly, and it even
changes as the mounting screws are tightened. Thus it is now stuck in the
mid position again. This is the third actuator we have had. The first
was a Potterton and quite sturdily made, but its backing plate was brittle
and broke when I went to replace the contacts. The replacement newer
Potterton only lasted about a year, before needing new contacts. Next
time I went for the Honeywell, which has, as above proven to be expensive
rubbish.

Are there any good ones out there?

S

Oops sorry: looking again, the second one we had was a Danfoss.

S

wrote in message ...
On 21 May,
"spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

--
B Thumbs

Sadly I don't feel up to any substantial replumbing at the mo: especially as
plumber has recently tapped the system with some new pipes for an upstairs
shower and routed them right in front of the pipes I'd need to get at...

S

wrote :
On 21 May,
"spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design
something more robust, which has the motor move the valve to the
correct position then stop - rather than the motor constantly
oscillating on the microswitches against the spring. Surprisingly, I
have not seen a DIY replacement actuator yet, but it doesn't look at
all difficult to do.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

"Harry Bloomfield" wrote in message
. uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design which
lets it so badly down. It simply needs someone to design something more
robust, which has the motor move the valve to the correct position then
stop - rather than the motor constantly oscillating on the microswitches
against the spring. Surprisingly, I have not seen a DIY replacement
actuator yet, but it doesn't look at all difficult to do.

--
Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have to buy
new every other year, there is not much incentive to come up with a
different design.

S

It happens that spamlet formulated :
"Harry Bloomfield" wrote in message
. uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design which
lets it so badly down. It simply needs someone to design something more
robust, which has the motor move the valve to the correct position then
stop - rather than the motor constantly oscillating on the microswitches
against the spring. Surprisingly, I have not seen a DIY replacement
actuator yet, but it doesn't look at all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have to buy
new every other year, there is not much incentive to come up with a different
design.

S

There is a rather good web site somewhere which explains their
principle of operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger
the two micro-switches - then a timer circuit to run it back to the
default position.

Even an electrically operated brake, which held the position and turned
off the motor - would be a major improvement on the existing botch of a
continual rocking motion.

Food for thought.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield laid this down on his screen :
It happens that spamlet formulated :
"Harry Bloomfield" wrote in message
. uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design which
lets it so badly down. It simply needs someone to design something more
robust, which has the motor move the valve to the correct position then
stop - rather than the motor constantly oscillating on the microswitches
against the spring. Surprisingly, I have not seen a DIY replacement
actuator yet, but it doesn't look at all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have to
buy new every other year, there is not much incentive to come up with a
different design.

S

There is a rather good web site somewhere which explains their principle of
operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger the two
micro-switches - then a timer circuit to run it back to the default position.

Even an electrically operated brake, which held the position and turned off
the motor - would be a major improvement on the existing botch of a continual
rocking motion.

Food for thought.

More food here...

http://www.seered.co.uk/sunvic.htm

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

spamlet laid this down on his screen :
there is not much incentive to come up with a different design.

It seems they may have...

http://www.sunvic.co.uk/momo_valves.htm

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Fri, 21 May 2010 15:48:02 +0100, spamlet wrote:

Is there such a thing? If so, does anyone have one they know to have
run trouble free for say 3 years: if so what make is it?

Our current one is a Honeywell, and is very rickety inside. I recently
had to look at the micro-switches and even found that one of them had
even been assembled with the contacts twisted! Even after straightening
the contacts getting the thing to balance properly again was very
fiddly, as all the springs and cams and the like are thin and wobbly,
and it even changes as the mounting screws are tightened. Thus it is
now stuck in the mid position again. This is the third actuator we have
had. The first was a Potterton and quite sturdily made, but its backing
plate was brittle and broke when I went to replace the contacts. The
replacement newer Potterton only lasted about a year, before needing new
contacts. Next time I went for the Honeywell, which has, as above
proven to be expensive rubbish.

Are there any good ones out there?



When we were doing boilerhouse panels we provided a lot of Landis &
Staefa (previously Landis & Gyr) and Sunvic valve actuators. We didn't
often get any problems. Mind you, the 3-port ones were often of the true
"proportional" type, with a feedback pot, and didn't use a motor-against-
spring system. I've no experience of current designs as we stopped doing
boilerhouse controls some years ago.

--
Mick (Working in a M$-free zone!)
Web: http://www.nascom.info
Filtering everything posted from googlegroups to kill spam.

In message , Harry
Bloomfield writes
It happens that spamlet formulated :
"Harry Bloomfield" wrote in
message . uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design
something more robust, which has the motor move the valve to the
correct position then stop - rather than the motor constantly
oscillating on the microswitches against the spring. Surprisingly, I
have not seen a DIY replacement actuator yet, but it doesn't look at
all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have
to buy new every other year, there is not much incentive to come up
with a different design.

S

There is a rather good web site somewhere which explains their
principle of operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger
the two micro-switches - then a timer circuit to run it back to the
default position.

Even an electrically operated brake, which held the position and turned
off the motor - would be a major improvement on the existing botch of a
continual rocking motion.

They used to manufacture 3 port valve actuator heads which would drive
to the correct position and then stop as the respective microswitch
opened, but they don't seem to be available any more

however, the synchron motors are quite cheap (I can get them for about
£7 locally or I could get them at £3 each if I bought 1000)


--
geoff

In article ,
"spamlet" writes:
Is there such a thing? If so, does anyone have one they know to have run
trouble free for say 3 years: if so what make is it?

Of the heating systems I maintain in various family members' homes,
I've never had one fail. (They're all mid position values.)

GBMVSP-23 (British Gas - don't know who makes it):
Somewhere between 10 and 20 years old.

Lifestyle (is that Drayton?):
11 years old.

Landis and Staefa:
7 years old.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
Harry Bloomfield writes:
wrote :
On 21 May,
"spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design
something more robust, which has the motor move the valve to the
correct position then stop - rather than the motor constantly
oscillating on the microswitches against the spring.

If it's doing that, it's wired in wrongly, or the internal
diode has gone open circuit. The motor is stopped in mid
position by having DC applied to the coil to lock the rotor.
It's locked in the far position by keeping the motor powered
but stalled. For spring return from mid position, there's a
resistor to leak a tiny AC current through the motor to
degauss the yoke after it's been locked with a DC field.

Surprisingly, I
have not seen a DIY replacement actuator yet, but it doesn't look at
all difficult to do.

Actually, it's quite an amasingly simple design to achieve
what it does with so little supplementary controls.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Harry Bloomfield" wrote in message
. uk...
It happens that spamlet formulated :
"Harry Bloomfield" wrote in message
. uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design something
more robust, which has the motor move the valve to the correct position
then stop - rather than the motor constantly oscillating on the
microswitches against the spring. Surprisingly, I have not seen a DIY
replacement actuator yet, but it doesn't look at all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have to
buy new every other year, there is not much incentive to come up with a
different design.

S

There is a rather good web site somewhere which explains their principle
of operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger the
two micro-switches - then a timer circuit to run it back to the default
position.

Even an electrically operated brake, which held the position and turned
off the motor - would be a major improvement on the existing botch of a
continual rocking motion.

Food for thought.


Yes: its on one of the UK-DIY faq pages and I've linked to it in earlier
threads.

S

"geoff" wrote in message
...
In message , Harry
Bloomfield writes
It happens that spamlet formulated :
"Harry Bloomfield" wrote in message
. uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design
something more robust, which has the motor move the valve to the
correct position then stop - rather than the motor constantly
oscillating on the microswitches against the spring. Surprisingly, I
have not seen a DIY replacement actuator yet, but it doesn't look at
all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have to
buy new every other year, there is not much incentive to come up with a
different design.

S

There is a rather good web site somewhere which explains their principle
of operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger the
two micro-switches - then a timer circuit to run it back to the default
position.

Even an electrically operated brake, which held the position and turned
off the motor - would be a major improvement on the existing botch of a
continual rocking motion.

They used to manufacture 3 port valve actuator heads which would drive to
the correct position and then stop as the respective microswitch opened,
but they don't seem to be available any more

however, the synchron motors are quite cheap (I can get them for about £7
locally or I could get them at £3 each if I bought 1000)


Yes, I've changed one before, but it is usually the microswitches that go
first, and then cause the motor to be on all the time, so just changing a
burnt out motor is quite likely to disappoint if the switches are not done
at the same time. The motors are quite similar to the ones on microwave
turntables.

S

"Harry Bloomfield" wrote in message
. uk...
spamlet laid this down on his screen :
there is not much incentive to come up with a different design.

It seems they may have...

http://www.sunvic.co.uk/momo_valves.htm

--
Regards,
Harry (M1BYT) (L)

Cheers Harry, I had forgotten about Sunvic - although part of our control
system is made by them.

Looks like the momo equivalent of the Danfoss is:

SDM 1901 - 3 Port Actuator £77.28

Pricey. but possibly worth it if it avoids all the hassle.

Cheers,
S

"Andrew Gabriel" wrote in message
...
In article ,
"spamlet" writes:
Is there such a thing? If so, does anyone have one they know to have run
trouble free for say 3 years: if so what make is it?

Of the heating systems I maintain in various family members' homes,
I've never had one fail. (They're all mid position values.)

GBMVSP-23 (British Gas - don't know who makes it):
Somewhere between 10 and 20 years old.

Lifestyle (is that Drayton?):
11 years old.

Landis and Staefa:
7 years old.

--
Andrew Gabriel

Thanks: I've not come across those types yet.

Cheers,
S

explained :
Is that a new thing, using diodes? The ones I've used have used a resistor to
put just enough power onto the motor to stall it, but not enough to let it
run back.

Now the diode has been mentioned, I do remember having seen one fitted
to one of our actuators in the past. The one I took off when it failed
about 12months ago, after just 12 months use, was installed when the
boiler was replaced with a new one. That actuator had no diodes and no
resistors - just the microswitches and the motor.

The present one fitted is/was a new Sunvic which was bought as spare
for when our old one died, prior to the new boiler. I had refurbed that
one several times and knew it was beyond being refurbed again.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In article ,
"spamlet" writes:

"Andrew Gabriel" wrote in message
...
In article ,
"spamlet" writes:
Is there such a thing? If so, does anyone have one they know to have run
trouble free for say 3 years: if so what make is it?

Of the heating systems I maintain in various family members' homes,
I've never had one fail. (They're all mid position values.)

GBMVSP-23 (British Gas - don't know who makes it):
Somewhere between 10 and 20 years old.

Lifestyle (is that Drayton?):
11 years old.

Landis and Staefa:
7 years old.

Actually that's wrong, must be 8-9 years old.

Thanks: I've not come across those types yet.

Go to a heating/plumbers merchant.
B&Q did keep the Lifestyle range, although that was in the days
before they made way for the cushions, but will still be much
cheaper from a plumbers merchant.

Landis and Staefa - I think they were bought by Siemens.
That's the only one I actually bought, and as I am controlling
it by a computer rather than conventional boiler/thermostat
controls, I had to work out exactly how to drive it. I had a
chat with someone in Landis and Staefa (or may have been whoever
bought them) who was incredible helpful and explained in detail
how to drive it. It's used as a zone valve to switch between
upstairs and downstairs heating zones.

I don't use the end-stop microswitch, so if that died, I wouldn't
notice. I did use it as a feedback control to confirm to the
computer that the valve was working initially, but I ran out of
spare computer inputs for other things so that extra test got
dropped.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Andrew Gabriel" wrote in message
...
In article ,
"spamlet" writes:

"Andrew Gabriel" wrote in message
...
In article ,
"spamlet" writes:
Is there such a thing? If so, does anyone have one they know to have
run
trouble free for say 3 years: if so what make is it?

Of the heating systems I maintain in various family members' homes,
I've never had one fail. (They're all mid position values.)

GBMVSP-23 (British Gas - don't know who makes it):
Somewhere between 10 and 20 years old.

Lifestyle (is that Drayton?):
11 years old.

Landis and Staefa:
7 years old.

Actually that's wrong, must be 8-9 years old.

Thanks: I've not come across those types yet.

Go to a heating/plumbers merchant.
B&Q did keep the Lifestyle range, although that was in the days
before they made way for the cushions, but will still be much
cheaper from a plumbers merchant.

Landis and Staefa - I think they were bought by Siemens.
That's the only one I actually bought, and as I am controlling
it by a computer rather than conventional boiler/thermostat
controls, I had to work out exactly how to drive it. I had a
chat with someone in Landis and Staefa (or may have been whoever
bought them) who was incredible helpful and explained in detail
how to drive it. It's used as a zone valve to switch between
upstairs and downstairs heating zones.

I don't use the end-stop microswitch, so if that died, I wouldn't
notice. I did use it as a feedback control to confirm to the
computer that the valve was working initially, but I ran out of
spare computer inputs for other things so that extra test got
dropped.
--
Andrew Gabriel

Phew! It's really impressive the things some of you guys are able to take
on. I'm afraid that with electronic stuff, I find, if I stare at it long
enough I can just about get a vague enough idea to see which part of it has
gone wrong, but as for designing my own stuff from scratch, and running it
off a computer, I think my head would probably explode! Are there any brain
upgraders out there I wonder?!

Cheers,
S

In message , spamlet
writes

"geoff" wrote in message
...
In message , Harry
Bloomfield writes
It happens that spamlet formulated :
"Harry Bloomfield" wrote in message
. uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design
something more robust, which has the motor move the valve to the
correct position then stop - rather than the motor constantly
oscillating on the microswitches against the spring. Surprisingly, I
have not seen a DIY replacement actuator yet, but it doesn't look at
all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have to
buy new every other year, there is not much incentive to come up with a
different design.

S

There is a rather good web site somewhere which explains their principle
of operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger the
two micro-switches - then a timer circuit to run it back to the default
position.

Even an electrically operated brake, which held the position and turned
off the motor - would be a major improvement on the existing botch of a
continual rocking motion.

They used to manufacture 3 port valve actuator heads which would drive to
the correct position and then stop as the respective microswitch opened,
but they don't seem to be available any more

however, the synchron motors are quite cheap (I can get them for about £7
locally or I could get them at £3 each if I bought 1000)


Yes, I've changed one before,

I've repaired hundreds

but it is usually the microswitches that go
first,

It depends on the make actually, believe it or not

for some reason Drayton heads seem particularly prone to microswitch
burnouts, irrespexctive of the uswitch make

and then cause the motor to be on all the time, so just changing a
burnt out motor is quite likely to disappoint if the switches are not done
at the same time.

Sorry, that's ********

The motors are quite similar to the ones on microwave
turntables.


.... Or exactly the same as the ones sold specifically for the task

--
geoff

"geoff" wrote in message
...
In message , spamlet
writes

"geoff" wrote in message
...
In message , Harry
Bloomfield writes
It happens that spamlet formulated :
"Harry Bloomfield" wrote in message
. uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much
more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design
something more robust, which has the motor move the valve to the
correct position then stop - rather than the motor constantly
oscillating on the microswitches against the spring. Surprisingly, I
have not seen a DIY replacement actuator yet, but it doesn't look at
all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have
to
buy new every other year, there is not much incentive to come up with
a
different design.

S

There is a rather good web site somewhere which explains their principle
of operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger
the
two micro-switches - then a timer circuit to run it back to the default
position.

Even an electrically operated brake, which held the position and turned
off the motor - would be a major improvement on the existing botch of a
continual rocking motion.

They used to manufacture 3 port valve actuator heads which would drive
to
the correct position and then stop as the respective microswitch opened,
but they don't seem to be available any more

however, the synchron motors are quite cheap (I can get them for about
£7
locally or I could get them at £3 each if I bought 1000)


Yes, I've changed one before,

I've repaired hundreds

but it is usually the microswitches that go
first,

It depends on the make actually, believe it or not

for some reason Drayton heads seem particularly prone to microswitch
burnouts, irrespexctive of the uswitch make

and then cause the motor to be on all the time, so just changing a
burnt out motor is quite likely to disappoint if the switches are not done
at the same time.

Sorry, that's ********
--
geoff

Well ******** or not that is what happened when I took my first one apart.
Motor was dead; replaced it and found it was on all the time; then opened up
microswitches and found one of them burnt out; replaced switch; motor no
longer on all the time. All ok for a year or so till switches burnt out
again. From other comments frequent in these columns this is quite
'normal'.

S

On Sat, 22 May 2010 02:13:07 +0100, spamlet wrote:

"Harry Bloomfield" wrote in message

http://www.sunvic.co.uk/momo_valves.htm

Cheers Harry, I had forgotten about Sunvic - although part of our control
system is made by them.

Looks like the momo equivalent of the Danfoss is:

SDM 1901 - 3 Port Actuator £77.28

Pricey. but possibly worth it if it avoids all the hassle.

I use the SDMV2304 3-port valve which is a drop-in replacement for
normal Honeywell-et-al valves, wiring wise, and are about £50 at B&Q.

There's a website run by someone who's disgruntled with these sorts of
valves as he says the electronics fails, due to high voltage spikes on the
mains I think, but I've never had it happen to any of the ones I've fitted.


--
John Stumbles -- http://yaph.co.uk

The rain, it rains upon the Just, and on the Unjust fella
But more upon the Just because the Unjust's got the Just's umbrella

On Fri, 21 May 2010 22:01:55 +0000, Andrew Gabriel wrote:

... For spring return from mid position, there's a
resistor to leak a tiny AC current through the motor to
degauss the yoke after it's been locked with a DC field.

Ah! is that what it's for?!

I always wondered.



--
John Stumbles -- http://yaph.co.uk

Who's *really* behind all these conspiracy theories?

"YAPH" wrote in message
...
On Sat, 22 May 2010 02:13:07 +0100, spamlet wrote:

"Harry Bloomfield" wrote in message

http://www.sunvic.co.uk/momo_valves.htm

Cheers Harry, I had forgotten about Sunvic - although part of our control
system is made by them.

Looks like the momo equivalent of the Danfoss is:

SDM 1901 - 3 Port Actuator £77.28

Pricey. but possibly worth it if it avoids all the hassle.

I use the SDMV2304 3-port valve which is a drop-in replacement for
normal Honeywell-et-al valves, wiring wise, and are about £50 at B&Q.

There's a website run by someone who's disgruntled with these sorts of
valves as he says the electronics fails, due to high voltage spikes on the
mains I think, but I've never had it happen to any of the ones I've
fitted.


--
John Stumbles -- http://yaph.co.uk

Well thanks for that John, it certainly looks promising and in some places
surprisingly cheap:

http://www.buyaparcel.com/pageview.p...ode =SDMV2304

However, I'm a bit confused as, although the various ads say it fits into
existing systems with no need to change pipework or controls, I can find no
pictures of the actuator on its own - so the implication is, it has it's own
dedicated valve. There are other pictures of actuators of the same make but
none look like the one pictured on the valve and they have several different
numbers of wires. Can anyone clear up this confusion? Do I have to buy the
whole thing and then just put the actuator on my old valve, or is this not
going to work? This 'buyaparcel' lot looks too good to be true if it's the
real momo deal!

Cheers,
S

In message , Harry
Bloomfield writes
It happens that spamlet formulated :
"Harry Bloomfield" wrote in
message . uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design
something more robust, which has the motor move the valve to the
correct position then stop - rather than the motor constantly
oscillating on the microswitches against the spring. Surprisingly, I
have not seen a DIY replacement actuator yet, but it doesn't look at
all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have
to buy new every other year, there is not much incentive to come up
with a different design.

S

There is a rather good web site somewhere which explains their
principle of operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger
the two micro-switches - then a timer circuit to run it back to the
default position.

Even an electrically operated brake, which held the position and turned
off the motor - would be a major improvement on the existing botch of a
continual rocking motion.


I'm somewhat confused about some of the comments so far. I have a
Honeywell 3 Port which I had to replace recently after 10 years of
service. It was itself a replacement for one that was 15 years old when
it died.

Anyway, the motor head had worn out its gears and research revealed the
downside of the system when used in my CH/HW setup. My CH timer is on
24/7 and the control is via a programmable thermostat in the living
room. I was shocked to learn that this invariably left the motor sitting
in the CH position with the full 240 volts applied to the motor so, I
devised a simple fix using a relay which returns the motor to the rest
position when the HW and CH thermostats are no longer calling for the
boiler.

My main confusion is with the "hunting" or "rocking motion" mentioned
and presumably this refers to the centre position i.e. HW and CH on, as
I have no such motion on my control head.

The motor moves to the central position, hunts once to find the second
microswitch and then sits there with no further movement.

--
Phil

"Phil" wrote in message ...
In message , Harry
Bloomfield writes
It happens that spamlet formulated :
"Harry Bloomfield" wrote in message
. uk...
wrote :
On 21 May, "spamlet" wrote:

Are there any good ones out there?

IME no. I've ended up changing to two port valves. They seem much more
reliable (10+years rather than 6 months)

Nothing at all wrong with the actual valve, just the actuator design
which lets it so badly down. It simply needs someone to design
something more robust, which has the motor move the valve to the
correct position then stop - rather than the motor constantly
oscillating on the microswitches against the spring. Surprisingly, I
have not seen a DIY replacement actuator yet, but it doesn't look at
all difficult to do.

-- Regards,
Harry (M1BYT) (L)

There's a job for you Harry: sign me up for one when you've sussed it!
I would imagine that while they have us over a barrel knowing we have to
buy new every other year, there is not much incentive to come up with a
different design.

S

There is a rather good web site somewhere which explains their principle
of operation and how to repair them.

It needs something like a tiny DC motor (to provide forward and reverse
motion), geared down to provide the torque, a two lobe cam to trigger the
two micro-switches - then a timer circuit to run it back to the default
position.

Even an electrically operated brake, which held the position and turned
off the motor - would be a major improvement on the existing botch of a
continual rocking motion.


I'm somewhat confused about some of the comments so far. I have a
Honeywell 3 Port which I had to replace recently after 10 years of
service. It was itself a replacement for one that was 15 years old when it
died.

Anyway, the motor head had worn out its gears and research revealed the
downside of the system when used in my CH/HW setup. My CH timer is on 24/7
and the control is via a programmable thermostat in the living room. I was
shocked to learn that this invariably left the motor sitting in the CH
position with the full 240 volts applied to the motor so, I devised a
simple fix using a relay which returns the motor to the rest position when
the HW and CH thermostats are no longer calling for the boiler.

My main confusion is with the "hunting" or "rocking motion" mentioned and
presumably this refers to the centre position i.e. HW and CH on, as I have
no such motion on my control head.

The motor moves to the central position, hunts once to find the second
microswitch and then sits there with no further movement.

--
Phil

I'm no expert on the electronics: just the faults. Possibly with your mod
the contacts last longer, but when they get burnt the motor can be heard
hunting and the pop pop pop each time it hits the contact can be picked up
on any radio you have near the device. Mine has just gone again: which will
be about three actuators and two sets of replacement contacts now. As yet I
haven't decided on what to buy this time. The 'momo' type has been
suggested, but no one has enlightened me yet as to whether a momo actuator
can be bought separately and directly replace the current spring type.

S