Just had to replace a CH zone valve that has probably been the cause of my
CH system’s intermittency. It looks like the motor is just too weak to
push the valve switching mechanism far enough to trigger the micro-switch.

Oddly, this hasn’t been happening all the time but yesterday it just
stopped triggering the CH altogether. Is this a normal failure mode for
these motors? Just curious.

The valve itself moves freely so there’s no resistance there. The motor
just seems too weak to work against the return spring.

Tim

--
Please don't feed the trolls

On 8 Dec 2023 11:25:18 GMT
Tim+ <timdownieuk@yahoo.co.youkay> wrote:

> Just had to replace a CH zone valve that has probably been the cause
> of my CH system’s intermittency. It looks like the motor is just too
> weak to push the valve switching mechanism far enough to trigger the
> micro-switch.
>
> Oddly, this hasn’t been happening all the time but yesterday it just
> stopped triggering the CH altogether. Is this a normal failure mode
> for these motors? Just curious.
>
> The valve itself moves freely so there’s no resistance there. The
> motor just seems too weak to work against the return spring.
>
> Tim
>

I noticed when I was playing with my valve recently (that sounds like a
Bishop and Actress joke!) that, operated manually, the valve opened, but
the microswitch was nowhere near being operated, so the system
downstream did not function. Whether this is normal, intentional, or
accidental, I have no idea, but it made troubleshooting more complex
than expected.

--
Davey.

Davey <davey@example.invalid> wrote:
> I noticed when I was playing with my valve recently (that sounds like a
> Bishop and Actress joke!) that, operated manually, the valve opened, but
> the microswitch was nowhere near being operated, so the system
> downstream did not function. Whether this is normal, intentional, or
> accidental, I have no idea, but it made troubleshooting more complex
> than expected.

In my old house there used to be something similar - pump would keep running
forever when the heating turned off. If I did a hard shutdown of the system
the pump would stop and stay stopped when power returned. My guess is that
the microswitch on the valve may have been sticky, which kept the pump
energised.

(not sure why it didn't come back when power was restored, but I don't know
how it was wired. 1970/80s system so not in any way sophisticated)

Theo

On 08/12/2023 11:25, Tim+ wrote:
>
> Just had to replace a CH zone valve that has probably been the cause of my
> CH system’s intermittency. It looks like the motor is just too weak to
> push the valve switching mechanism far enough to trigger the micro-switch.
>
> Oddly, this hasn’t been happening all the time but yesterday it just
> stopped triggering the CH altogether. Is this a normal failure mode for
> these motors? Just curious.
>
> The valve itself moves freely so there’s no resistance there. The motor
> just seems too weak to work against the return spring.
>
That can happen, yes. There is very little power in those motors and
they gearboxes can dry up and add friction

Its cheap enough to just replace the head anyway.

I think I had to replace just one in 20 years.

> Tim
>

--
Ideas are more powerful than guns. We would not let our enemies have
guns, why should we let them have ideas?

Josef Stalin

On 08/12/2023 11:59, Davey wrote:
> On 8 Dec 2023 11:25:18 GMT
> Tim+ <timdownieuk@yahoo.co.youkay> wrote:
>
>> Just had to replace a CH zone valve that has probably been the cause
>> of my CH system’s intermittency. It looks like the motor is just too
>> weak to push the valve switching mechanism far enough to trigger the
>> micro-switch.
>>
>> Oddly, this hasn’t been happening all the time but yesterday it just
>> stopped triggering the CH altogether. Is this a normal failure mode
>> for these motors? Just curious.
>>
>> The valve itself moves freely so there’s no resistance there. The
>> motor just seems too weak to work against the return spring.
>>
>> Tim
>>
>
> I noticed when I was playing with my valve recently (that sounds like a
> Bishop and Actress joke!) that, operated manually, the valve opened, but
> the microswitch was nowhere near being operated, so the system
> downstream did not function. Whether this is normal, intentional, or
> accidental, I have no idea, but it made troubleshooting more complex
> than expected.
>
I think I saw that behaviour on mine too. Before I replaced it.

Once replaced I no longer cared....so I dunno if its normal

--
“There are two ways to be fooled. One is to believe what isn’t true; the
other is to refuse to believe what is true.”

—Soren Kierkegaard

On 08/12/2023 11:59, Davey wrote:
> On 8 Dec 2023 11:25:18 GMT
> Tim+ <timdownieuk@yahoo.co.youkay> wrote:
>
>> Just had to replace a CH zone valve that has probably been the cause
>> of my CH system’s intermittency. It looks like the motor is just too
>> weak to push the valve switching mechanism far enough to trigger the
>> micro-switch.
>>
>> Oddly, this hasn’t been happening all the time but yesterday it just
>> stopped triggering the CH altogether. Is this a normal failure mode
>> for these motors? Just curious.
>>
>> The valve itself moves freely so there’s no resistance there. The
>> motor just seems too weak to work against the return spring.
>>
>> Tim
>>
>
> I noticed when I was playing with my valve recently (that sounds like a
> Bishop and Actress joke!) that, operated manually, the valve opened, but
> the microswitch was nowhere near being operated, so the system
> downstream did not function. Whether this is normal, intentional, or
> accidental, I have no idea, but it made troubleshooting more complex
> than expected.

If you operate the leaver on the side of the valve, then that does not
usually drive it far enough to close the switch...

--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

On 08/12/2023 11:25, Tim+ wrote:
>
> Just had to replace a CH zone valve that has probably been the cause of my
> CH system’s intermittency. It looks like the motor is just too weak to
> push the valve switching mechanism far enough to trigger the micro-switch.
>
> Oddly, this hasn’t been happening all the time but yesterday it just
> stopped triggering the CH altogether. Is this a normal failure mode for
> these motors? Just curious.
>
> The valve itself moves freely so there’s no resistance there. The motor
> just seems too weak to work against the return spring.

Th synchron motors failing is not that uncommon - sometimes "helped" by
a stiff mechanism.

Usual fix is to get a new motor, take the old one off, add some oil to
the valve shaft and work back and forward with pliers, until is moves
freely. Then stick the new motor on.

--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

On 08/12/2023 13:21, The Natural Philosopher wrote:
> On 08/12/2023 11:25, Tim+ wrote:
>>
>> Just had to replace a CH zone valve that has probably been the cause
>> of my
>> CH system’s intermittency.  It looks like the motor is just too weak to
>> push the valve switching mechanism far enough to trigger the
>> micro-switch.
>>
>> Oddly, this hasn’t been happening all the time but yesterday it just
>> stopped triggering the CH altogether.  Is this a normal failure mode for
>> these motors? Just curious.
>>
>> The valve itself moves freely so there’s no resistance there. The motor
>> just seems too weak to work against the return spring.
>>
> That can happen, yes. There is very little power in those motors and
> they gearboxes can dry up and add friction
>
> Its cheap enough to just replace the head anyway.
>
> I think I had to replace just one in 20 years.

I've had problems with microswitches. The switching plunger was plastic
and with a VERY small movement to get it to switch. Over the years the
plastic plunger had worn down slightly and no longer reliably operated
the switch.

In this case it was on a very old boiler and part of the pump over-run.
It was all mechanical with a bi-metal strip operating the micro-switch
plunger.
When the system stopped calling for heat this parallel microswitch
circuit was meant to still provide power to the pump while the boiler
remained hot. When the circuit failed the micro-switch wasn't made and
the pump stopped immediately when there was no call for heat. The latent
heat in the burner boiled the now static water resulting in loud banging :(

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Davey <davey@example.invalid> wrote:
> On 8 Dec 2023 11:25:18 GMT
> Tim+ <timdownieuk@yahoo.co.youkay> wrote:
>
>> Just had to replace a CH zone valve that has probably been the cause
>> of my CH system’s intermittency. It looks like the motor is just too
>> weak to push the valve switching mechanism far enough to trigger the
>> micro-switch.
>>
>> Oddly, this hasn’t been happening all the time but yesterday it just
>> stopped triggering the CH altogether. Is this a normal failure mode
>> for these motors? Just curious.
>>
>> The valve itself moves freely so there’s no resistance there. The
>> motor just seems too weak to work against the return spring.
>>
>> Tim
>>
>
> I noticed when I was playing with my valve recently (that sounds like a
> Bishop and Actress joke!) that, operated manually, the valve opened, but
> the microswitch was nowhere near being operated, so the system
> downstream did not function. Whether this is normal, intentional, or
> accidental, I have no idea, but it made troubleshooting more complex
> than expected.
>

Indeed, I noticed that too. Not quite sure why it’s not designed to
activate the microswitch in manual mode but that certainly seems to be the
case.

Tim

--
Please don't feed the trolls

On 08/12/2023 14:36, Tim+ wrote:
> Davey <davey@example.invalid> wrote:
>> On 8 Dec 2023 11:25:18 GMT
>> Tim+ <timdownieuk@yahoo.co.youkay> wrote:
>>
>>> Just had to replace a CH zone valve that has probably been the cause
>>> of my CH system’s intermittency. It looks like the motor is just too
>>> weak to push the valve switching mechanism far enough to trigger the
>>> micro-switch.
>>>
>>> Oddly, this hasn’t been happening all the time but yesterday it just
>>> stopped triggering the CH altogether. Is this a normal failure mode
>>> for these motors? Just curious.
>>>
>>> The valve itself moves freely so there’s no resistance there. The
>>> motor just seems too weak to work against the return spring.
>>>
>>> Tim
>>>
>>
>> I noticed when I was playing with my valve recently (that sounds like a
>> Bishop and Actress joke!) that, operated manually, the valve opened, but
>> the microswitch was nowhere near being operated, so the system
>> downstream did not function. Whether this is normal, intentional, or
>> accidental, I have no idea, but it made troubleshooting more complex
>> than expected.
>>
>
> Indeed, I noticed that too. Not quite sure why it’s not designed to
> activate the microswitch in manual mode but that certainly seems to be the
> case.

I think practical constrains win the day. When the motor is energised it
must 'unlatch' the manual mode.

If the microswitch was closed when held in manual mode, it could never
move to fully open, nor unlatch the manual mode.

On Fri, 8 Dec 2023 14:48:53 +0000
Fredxx <fredxx@spam.invalid> wrote:

> >> I noticed when I was playing with my valve recently (that sounds
> >> like a Bishop and Actress joke!) that, operated manually, the
> >> valve opened, but the microswitch was nowhere near being operated,
> >> so the system downstream did not function. Whether this is normal,
> >> intentional, or accidental, I have no idea, but it made
> >> troubleshooting more complex than expected.
> >>
> >
> > Indeed, I noticed that too. Not quite sure why it’s not designed to
> > activate the microswitch in manual mode but that certainly seems to
> > be the case.
>
> I think practical constrains win the day. When the motor is energised
> it must 'unlatch' the manual mode.
>
> If the microswitch was closed when held in manual mode, it could
> never move to fully open, nor unlatch the manual mode.

The manual mode is unlatched by unhooking the lever, which is hooked
into the 'Open' position manually. It will stay there until
manually unlatched, whatever the motor does. I believe, from memory.
I'll check it when I get the chance.

With the manual mode not operating the microswitch, troubleshooting is
made more difficult than if it did operate it. The very thing you are
trying to prove or disprove is not duplicated by manual operation, which
is why you are doing it in the first place!
--
Davey.

On 08/12/2023 11:25, Tim+ wrote:
>
> Just had to replace a CH zone valve that has probably been the cause of my
> CH system’s intermittency. It looks like the motor is just too weak to
> push the valve switching mechanism far enough to trigger the micro-switch.
>
> Oddly, this hasn’t been happening all the time but yesterday it just
> stopped triggering the CH altogether. Is this a normal failure mode for
> these motors? Just curious.
>
> The valve itself moves freely so there’s no resistance there. The motor
> just seems too weak to work against the return spring.
>
> Tim
>

The Honeywell specs for the valve and return spring actions are/were:

less than 12 seconds for a powered motor to complete the valve action.

less than 6 seconds for the spring to fully retract.

Check it out !

PA

John Rumm <see.my.signature@nowhere.null> wrote:
> On 08/12/2023 11:25, Tim+ wrote:
>>
>> Just had to replace a CH zone valve that has probably been the cause of my
>> CH system’s intermittency. It looks like the motor is just too weak to
>> push the valve switching mechanism far enough to trigger the micro-switch.
>>
>> Oddly, this hasn’t been happening all the time but yesterday it just
>> stopped triggering the CH altogether. Is this a normal failure mode for
>> these motors? Just curious.
>>
>> The valve itself moves freely so there’s no resistance there. The motor
>> just seems too weak to work against the return spring.
>
> Th synchron motors failing is not that uncommon - sometimes "helped" by
> a stiff mechanism.
>
> Usual fix is to get a new motor, take the old one off, add some oil to
> the valve shaft and work back and forward with pliers, until is moves
> freely. Then stick the new motor on.
>

Well I did a PM on the old motor and it looks like it was wear in the
curved rack that was the problem. When it got to a certain part of its
travel the drive pinion would either jam or start slipping.

The actual drive pinion on the motor looks okay so I’ll keep the motor as a
spare. It doesn’t display any lack of torque so I don’t think the motor
was ever the problem.

Tim

--
Please don't feed the trolls

On 08/12/2023 17:27, Davey wrote:

> The manual mode is unlatched by unhooking the lever, which is hooked
> into the 'Open' position manually. It will stay there until
> manually unlatched, whatever the motor does.

My 3 port valve doesn't. It stays latched until the motor drives it to
the CH only position. Initially, and because I hadn't RTFM, this fooled
me. It was summer when I filled the system and at first I couldn't work
out why when I only wanted hot water the radiators would also become
hot. The 3 port was latched in its mid position. Setting the controls to
ch only released the latching mechanism after which the valve operated
normally.

The valve is a Drayton mid position 22mm valve.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 08/12/2023 18:36, Tim+ wrote:
> John Rumm <see.my.signature@nowhere.null> wrote:
>> On 08/12/2023 11:25, Tim+ wrote:
>>>
>>> Just had to replace a CH zone valve that has probably been the cause of my
>>> CH system’s intermittency. It looks like the motor is just too weak to
>>> push the valve switching mechanism far enough to trigger the micro-switch.
>>>
>>> Oddly, this hasn’t been happening all the time but yesterday it just
>>> stopped triggering the CH altogether. Is this a normal failure mode for
>>> these motors? Just curious.
>>>
>>> The valve itself moves freely so there’s no resistance there. The motor
>>> just seems too weak to work against the return spring.
>>
>> Th synchron motors failing is not that uncommon - sometimes "helped" by
>> a stiff mechanism.
>>
>> Usual fix is to get a new motor, take the old one off, add some oil to
>> the valve shaft and work back and forward with pliers, until is moves
>> freely. Then stick the new motor on.
>>
>
> Well I did a PM on the old motor and it looks like it was wear in the
> curved rack that was the problem. When it got to a certain part of its
> travel the drive pinion would either jam or start slipping.
>
Sounds pretty reasonable. A new hear will solve that problem

> The actual drive pinion on the motor looks okay so I’ll keep the motor as a
> spare. It doesn’t display any lack of torque so I don’t think the motor
> was ever the problem.
>
The motors seldom if ever burn out. Its usually wear or corriosion or
oil drying up in the mechanism.

> Tim
>

--
Ideas are more powerful than guns. We would not let our enemies have
guns, why should we let them have ideas?

Josef Stalin

On 08/12/2023 11:25, Tim+ wrote:
> The valve itself moves freely so there’s no resistance there. The motor
> just seems too weak to work against the return spring.

The lub dries up, the mechanism becomes less free, and they fail due to
the heat, Yes. My 3-port valves, tended to last around two or three
years, max. such a regular failure, I always keep one spare, ready to
swap in.

On Fri, 8 Dec 2023 18:51:46 +0000
alan_m <junk@admac.myzen.co.uk> wrote:

> On 08/12/2023 17:27, Davey wrote:
>
> > The manual mode is unlatched by unhooking the lever, which is hooked
> > into the 'Open' position manually. It will stay there until
> > manually unlatched, whatever the motor does.
>
> My 3 port valve doesn't. It stays latched until the motor drives it
> to the CH only position. Initially, and because I hadn't RTFM, this
> fooled me. It was summer when I filled the system and at first I
> couldn't work out why when I only wanted hot water the radiators
> would also become hot. The 3 port was latched in its mid position.
> Setting the controls to ch only released the latching mechanism after
> which the valve operated normally.
>
> The valve is a Drayton mid position 22mm valve.
>
>

Mine is a Honeywell. I'll try and check it out in the morning.

--
Davey.

On Sat, 9 Dec 2023 00:14:58 +0000
Davey <davey@example.invalid> wrote:

> On Fri, 8 Dec 2023 18:51:46 +0000
> alan_m <junk@admac.myzen.co.uk> wrote:
>
> > On 08/12/2023 17:27, Davey wrote:
> >
> > > The manual mode is unlatched by unhooking the lever, which is
> > > hooked into the 'Open' position manually. It will stay there until
> > > manually unlatched, whatever the motor does.
> >
> > My 3 port valve doesn't. It stays latched until the motor drives it
> > to the CH only position. Initially, and because I hadn't RTFM, this
> > fooled me. It was summer when I filled the system and at first I
> > couldn't work out why when I only wanted hot water the radiators
> > would also become hot. The 3 port was latched in its mid position.
> > Setting the controls to ch only released the latching mechanism
> > after which the valve operated normally.
> >
> > The valve is a Drayton mid position 22mm valve.
> >
> >
>
> Mine is a Honeywell. I'll try and check it out in the morning.
>

I bow to superior knowledge. It behaves exactly as described by alan_m.
This also comes under the heading: "You learn something every day".

--
Davey.

On 08/12/2023 22:54, Harry Bloomfield Esq wrote:
> On 08/12/2023 11:25, Tim+ wrote:
>> The valve itself moves freely so there’s no resistance there. The motor
>> just seems too weak to work against the return spring.
>
> The lub dries up, the mechanism becomes less free, and they fail due to
> the heat, Yes. My 3-port valves, tended to last around two or three
> years, max. such a regular failure, I always keep one spare, ready to
> swap in.

That is truly - er - shit!

--
"A point of view can be a dangerous luxury when substituted for insight
and understanding".

Marshall McLuhan

Davey <davey@example.invalid> wrote:

> On Fri, 8 Dec 2023 18:51:46 +0000 alan_m <junk@admac.myzen.co.uk> wrote:
>
> > On 08/12/2023 17:27, Davey wrote:
> >
> > > The manual mode is unlatched by unhooking the lever, which is hooked
> > > into the 'Open' position manually. It will stay there until manually
> > > unlatched, whatever the motor does.
> >
> > My 3 port valve doesn't. It stays latched until the motor drives it to
> > the CH only position. Initially, and because I hadn't RTFM, this fooled
> > me. It was summer when I filled the system and at first I couldn't work
> > out why when I only wanted hot water the radiators would also become
> > hot. The 3 port was latched in its mid position. Setting the controls to
> > ch only released the latching mechanism after which the valve operated
> > normally.
> >
> > The valve is a Drayton mid position 22mm valve.
> >
> >
>
> Mine is a Honeywell. I'll try and check it out in the morning.
>
I've found mid position valves unreliable, all now changed to 2 port valves.
I needed to get microswitches in bulk.

--
braind

On 10/12/2023 00:47, me9 wrote:

> I've found mid position valves unreliable, all now changed to 2 port valves.
> I needed to get microswitches in bulk.
>

In 30 years on my CH system I've only had to replace one 3 port valve.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Sun, 10 Dec 2023 00:47:00 +0000
me9 <me9@privacy.net> wrote:

> Davey <davey@example.invalid> wrote:
>
> > On Fri, 8 Dec 2023 18:51:46 +0000 alan_m <junk@admac.myzen.co.uk>
> > wrote:
> > > On 08/12/2023 17:27, Davey wrote:
> > >
> > > > The manual mode is unlatched by unhooking the lever, which is
> > > > hooked into the 'Open' position manually. It will stay there
> > > > until manually unlatched, whatever the motor does.
> > >
> > > My 3 port valve doesn't. It stays latched until the motor drives
> > > it to the CH only position. Initially, and because I hadn't
> > > RTFM, this fooled me. It was summer when I filled the system and
> > > at first I couldn't work out why when I only wanted hot water the
> > > radiators would also become hot. The 3 port was latched in its
> > > mid position. Setting the controls to ch only released the
> > > latching mechanism after which the valve operated normally.
> > >
> > > The valve is a Drayton mid position 22mm valve.
> > >
> > >
> >
> > Mine is a Honeywell. I'll try and check it out in the morning.
> >
> I've found mid position valves unreliable, all now changed to 2 port
> valves. I needed to get microswitches in bulk.
>

The only one I have is a 2-port unit. I think I should be glad.
--
Davey.

On 10/12/2023 00:47, me9 wrote:
> I've found mid position valves unreliable, all now changed to 2 port valves.
> I needed to get microswitches in bulk.

The MOMO design of 3-port seem, by design, to be more reliable - no
springs involved, no deliberate stalling of the motor under power. They
just motor to position, then switch completely off, until called to move
again.

In article <ul4bij$2kmd7$3@dont-email.me>, Harry Bloomfield Esq
<a@harrym1byt.plus.com> wrote:
> On 10/12/2023 00:47, me9 wrote:
> > I've found mid position valves unreliable, all now changed to 2 port
> > valves. I needed to get microswitches in bulk.

> The MOMO design of 3-port seem, by design, to be more reliable - no
> springs involved, no deliberate stalling of the motor under power. They
> just motor to position, then switch completely off, until called to move
> again.

There are two port valves like that, too. They are making comeback.

--
from KT24 in Surrey, England - sent from my RISC OS 4té²
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 10/12/2023 01:32, alan_m wrote:
> On 10/12/2023 00:47, me9 wrote:
>
>> I've found mid position valves unreliable, all now changed to 2 port
>> valves.
>> I needed to get microswitches in bulk.
>>
>
> In 30 years on my CH system I've only had to replace one 3 port valve.
>
A lot depends on how much limescale build up you get. A good
installation with no leaks and full of additive in a soft water area is
fine. But when you are in a hard water area and a lot of topping up
without additives goes on - typically because of a failed pressure
vessel or minor weeping from some gland - you get scale build up the
jams the valves.
--
"When one man dies it's a tragedy. When thousands die it's statistics."

Josef Stalin