Our Myson Kickspace 500 heater has taken to sometimes not spinning up when
the CH is on. There’s an internal normally open stat that detects the flow
temperature to turn the fan off when the central heating goes off.

With the heater out on the floor and the CH on, the fan runs, but unevenly,
and I’m wondering if the contacts in the stat have become a bit “iffy”.

The stat is a small two terminal “button” shaped thing that’s clipped
against a pipe. A pretty standard component but I’m not sure of it’s
proper name.

It has F41C 9958 5 Z14 08 stamped on the face of it (the face that is
applied to the pipe).

Would I be right in thinking the 41C is the closing temperature? I’m
guessing 08 might be the year of manufacture.

I can probably get one from Myson but just wondering if there would be
cheaper alternatives. Knowing the correct name and nomenclature of this
type of stat would help in my searches.

Tim

--
Please don't feed the trolls

On Wednesday, 2 November 2022 at 11:29:02 UTC, Tim+ wrote:
> Our Myson Kickspace 500 heater has taken to sometimes not spinning up when
> the CH is on. There’s an internal normally open stat that detects the flow
> temperature to turn the fan off when the central heating goes off.
>
> With the heater out on the floor and the CH on, the fan runs, but unevenly,
> and I’m wondering if the contacts in the stat have become a bit “iffy”.
>
> The stat is a small two terminal “button” shaped thing that’s clipped
> against a pipe. A pretty standard component but I’m not sure of it’s
> proper name.
>
> It has F41C 9958 5 Z14 08 stamped on the face of it (the face that is
> applied to the pipe).
>
> Would I be right in thinking the 41C is the closing temperature? I’m
> guessing 08 might be the year of manufacture.
>
> I can probably get one from Myson but just wondering if there would be
> cheaper alternatives. Knowing the correct name and nomenclature of this
> type of stat would help in my searches.
>
> Tim
>
> --
> Please don't feed the trolls

Picture would be nice but does it look like this

https://uk.rs-online.com/web/p/thermostatic-switches/2282636
41C sounds to specific, when 42 would be the answer to everyfing ;-)

I'm not sure if numbers of these things make logical sense.

a google searcdh for the number gave me this but not that useful either.
https://www.farnell.com/datasheets/1927612.pdf

whisky-dave <whisky.dave@gmail.com> wrote:
> On Wednesday, 2 November 2022 at 11:29:02 UTC, Tim+ wrote:
>> Our Myson Kickspace 500 heater has taken to sometimes not spinning up when
>> the CH is on. There’s an internal normally open stat that detects the flow
>> temperature to turn the fan off when the central heating goes off.
>>
>> With the heater out on the floor and the CH on, the fan runs, but unevenly,
>> and I’m wondering if the contacts in the stat have become a bit “iffy”.
>>
>> The stat is a small two terminal “button” shaped thing that’s clipped
>> against a pipe. A pretty standard component but I’m not sure of it’s
>> proper name.
>>
>> It has F41C 9958 5 Z14 08 stamped on the face of it (the face that is
>> applied to the pipe).
>>
>> Would I be right in thinking the 41C is the closing temperature? I’m
>> guessing 08 might be the year of manufacture.
>>
>> I can probably get one from Myson but just wondering if there would be
>> cheaper alternatives. Knowing the correct name and nomenclature of this
>> type of stat would help in my searches.
>>
>> Tim
>>
>> --
>> Please don't feed the trolls
>
> Picture would be nice but does it look like this
>
> https://uk.rs-online.com/web/p/thermostatic-switches/2282636
> 41C sounds to specific, when 42 would be the answer to everyfing ;-)
>
> I'm not sure if numbers of these things make logical sense.
>
> a google searcdh for the number gave me this but not that useful either.
> https://www.farnell.com/datasheets/1927612.pdf
>

It’s that kind of thing although mine is normally open at low temp, and
then closes once the temperature rises above a certain level.

I decided to phone Myson who think that the stat is unlikely to be the
issue. They either work or they don’t, they don’t “half fail” with poor
conductivities and they suggested that the motor speed variation is more
likely down to just the age of the motor. Apparently the stat should close
at 31C.

After this conversation I shorted out the stat and indeed the motor speed
did still wander about a bit (on the low speed setting) which fits with
what they said.

Not sure why it’s just not starting sometimes. May still be a motor issue
but to complicate things I have an external wireless room stat also
controlling the supply to the fan so I may need to delve into that.

Tim
--
Please don't feed the trolls

On 2 Nov 2022 13:46:39 GMT
Tim+ <tim.downie@gmail.com> wrote:

> Not sure why it’s just not starting sometimes.

I'd suspect crusty lube in the bearings, or just badly worn bearings.

Rob Morley <nospam@ntlworld.com> wrote:
> On 2 Nov 2022 13:46:39 GMT
> Tim+ <tim.downie@gmail.com> wrote:
>
>> Not sure why it’s just not starting sometimes.
>
> I'd suspect crusty lube in the bearings, or just badly worn bearings.
>
>

That was my first thought but the fan spins freely and silently if I give
it a poke.

Tim

--
Please don't feed the trolls

On 2 Nov 2022 14:56:55 GMT
Tim+ <tim.downie@gmail.com> wrote:

> That was my first thought but the fan spins freely and silently if I
> give it a poke.
>
It's not a brushed motor is it?

Rob Morley <nospam@ntlworld.com> wrote:
> On 2 Nov 2022 14:56:55 GMT
> Tim+ <tim.downie@gmail.com> wrote:
>
>> That was my first thought but the fan spins freely and silently if I
>> give it a poke.
>>
> It's not a brushed motor is it?
>
No, brushless. I think it’s what’s called a “squirrel cage” motor.

Tim

--
Please don't feed the trolls

On 02/11/2022 13:37, whisky-dave wrote:

>
> https://uk.rs-online.com/web/p/thermostatic-switches/2282636
> 41C sounds to specific, when 42 would be the answer to everyfing ;-)

:-)

Very good

On Wednesday, 2 November 2022 at 14:56:59 UTC, Tim+ wrote:
> That was my first thought but the fan spins freely and silently if I give
> it a poke.

You need a solenoid then to give it a poke automatically on call-for-heat then :)

Owain

On Wed, 2 Nov 2022 10:56:35 -0700 (PDT)
Owain Lastname <spuorgelgoog@gowanhill.com> wrote:

> You need a solenoid then to give it a poke automatically on
> call-for-heat then :)
>
A solenoid controlled valve hooked up to a compressed air source to
blow the fan into action might be easier to arrange than a mechanical
prodder. 8:)

On Wednesday, 2 November 2022 at 13:46:44 UTC, Tim+ wrote:
> whisky-dave <whisk...@gmail.com> wrote:
> > On Wednesday, 2 November 2022 at 11:29:02 UTC, Tim+ wrote:
> >> Our Myson Kickspace 500 heater has taken to sometimes not spinning up when
> >> the CH is on. There’s an internal normally open stat that detects the flow
> >> temperature to turn the fan off when the central heating goes off.
> >>
> >> With the heater out on the floor and the CH on, the fan runs, but unevenly,
> >> and I’m wondering if the contacts in the stat have become a bit “iffy”.
> >>
> >> The stat is a small two terminal “button” shaped thing that’s clipped
> >> against a pipe. A pretty standard component but I’m not sure of it’s
> >> proper name.
> >>
> >> It has F41C 9958 5 Z14 08 stamped on the face of it (the face that is
> >> applied to the pipe).
> >>
> >> Would I be right in thinking the 41C is the closing temperature? I’m
> >> guessing 08 might be the year of manufacture.
> >>
> >> I can probably get one from Myson but just wondering if there would be
> >> cheaper alternatives. Knowing the correct name and nomenclature of this
> >> type of stat would help in my searches.
> >>
> >> Tim
> >>
> >> --
> >> Please don't feed the trolls
> >
> > Picture would be nice but does it look like this
> >
> > https://uk.rs-online.com/web/p/thermostatic-switches/2282636
> > 41C sounds to specific, when 42 would be the answer to everyfing ;-)
> >
> > I'm not sure if numbers of these things make logical sense.
> >
> > a google searcdh for the number gave me this but not that useful either..
> > https://www.farnell.com/datasheets/1927612.pdf
> >
> It’s that kind of thing although mine is normally open at low temp, and
> then closes once the temperature rises above a certain level.
>
> I decided to phone Myson who think that the stat is unlikely to be the
> issue. They either work or they don’t, they don’t “half fail” with poor
> conductivities and they suggested that the motor speed variation is more
> likely down to just the age of the motor. Apparently the stat should close
> at 31C.
>
> After this conversation I shorted out the stat and indeed the motor speed
> did still wander about a bit (on the low speed setting) which fits with
> what they said.
>
> Not sure why it’s just not starting sometimes. May still be a motor issue
> but to complicate things I have an external wireless room stat also
> controlling the supply to the fan so I may need to delve into that.
> Tim

Age isn't really the cause. Bad lube can cause stall, slow speedup, reduced speed & overheating, but not often wavering speed.
Bad bearings can cause speed wavering, but are very noisy.
I'd clean/lube the bearings & suspect the dropper if there is one, but more likely there isn't.