When they only go so far but keep clicking it is always a duff microswitch. Just replaceboth of them while you have the thing open. It is nothing to do with stripped teeth or the gear box. The contacts in the micro switches need to be switching off and on the boiler and the pump which are highly inductive. In a nut shell the contacts are going to spark and get a hammering. One solution for a longer life is to fit supression capacitors across the contacts, problem is fitting them in.

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On Sat, 24 Dec 2022 10:15:03 +1100, SAUSAGE
<8c3fd8c6885b3cbdf22e0e7112423315@example.com> wrote:

> When they only go so far but keep clicking it is always a duff
> microswitch. Just replaceboth of them while you have the thing open. It
> is nothing to do with stripped teeth or the gear box. The contacts in
> the micro switches need to be switching off and on the boiler and the
> pump which are highly inductive. In a nut shell the contacts are going
> to spark and get a hammering. One solution for a longer life is to fit
> supression capacitors across the contacts, problem is fitting them in.

You are only 9 years late, you silly sausage.

On Friday, 23 December 2022 at 23:15:07 UTC, SAUSAGE wrote:
> When they only go so far but keep clicking it is always a duff microswitch. Just replaceboth of them while you have the thing open. It is nothing to do with stripped teeth or the gear box. The contacts in the micro switches need to be switching off and on the boiler and the pump which are highly inductive. In a nut shell the contacts are going to spark and get a hammering. One solution for a longer life is to fit supression capacitors across the contacts, problem is fitting them in.
>
> --
> For full context, visit https://www.homeownershub.com/uk-diy/sunvic-sd2701-actuator-881788-.htm
Where do these loons emerge from?

Yes I thought that, but it also begs the question as to why suppression is
not fitted as standard in the first place.
Brian

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"chop" <chop654@gmail.com> wrote in message
news:op.1xnlx8qmnuhhzz@pvr2.lan...
> On Sat, 24 Dec 2022 10:15:03 +1100, SAUSAGE
> <8c3fd8c6885b3cbdf22e0e7112423315@example.com> wrote:
>
>> When they only go so far but keep clicking it is always a duff
>> microswitch. Just replaceboth of them while you have the thing open. It
>> is nothing to do with stripped teeth or the gear box. The contacts in
>> the micro switches need to be switching off and on the boiler and the
>> pump which are highly inductive. In a nut shell the contacts are going
>> to spark and get a hammering. One solution for a longer life is to fit
>> supression capacitors across the contacts, problem is fitting them in.
>
> You are only 9 years late, you silly sausage.

On Friday, 23 December 2022 at 23:52:55 UTC, chop wrote:
> On Sat, 24 Dec 2022 10:15:03 +1100, SAUSAGE
> <8c3fd8c6885b3cbd...@example.com> wrote:
>
> > When they only go so far but keep clicking it is always a duff
> > microswitch. Just replaceboth of them while you have the thing open. It
> > is nothing to do with stripped teeth or the gear box. The contacts in
> > the micro switches need to be switching off and on the boiler and the
> > pump which are highly inductive. In a nut shell the contacts are going
> > to spark and get a hammering. One solution for a longer life is to fit
> > supression capacitors across the contacts, problem is fitting them in.
> You are only 9 years late, you silly sausage.

replying to the wrong realm too.

On 24/12/2022 12:29, Brian Gaff wrote:
> Yes I thought that, but it also begs the question as to why suppression is
> not fitted as standard in the first place.

Because it's not needed, they don't 'spark'. The cam hits the switch,
operates the contacts, which are then designed to simply stall the motor
at that position.

I think the poster assumed the micro-switch caused the motor to
continually switch on and off, winding and unwinding on the spring,
constantly switching the microswitch.

They are not fitted because there is no room in the enclosure to do that, plus Sunvic don't care what happens after the six month warranty runs out. Harry, they do spark. The CH or HW call signal passes through them to actually fire the boiler and pump up. The mid position is held by feeding the motor with half wave mains through the diode and resistor, and a reduced demagitising signal on the other half of the mains with another resistor. I have never indicated that the microswithes are designed to switch the motor off and on in the mid position. I was trying to point our that when switch number 2 fails, the motor gets no half wave mains from the diode. It then spring returns back until switch number 1 kicks in again and starts heading back to mid position, and so forth. This is when people get the classic clicking situation coming from the cam constantly operating switch number 1 . The last phone call I had with Sunvic indicated that their engineers no longer know what the diode and resistors are actually for which says everything about them. The last call I had with 'Synchron' indicated that the motors were never designed for this purpose and accept no responsibility. My final
solution : Use the microswitches to operate 12 volt relays which then do all the switching externally, with higher current rated contacts (again with capacitors fitted). Ditch the mid position altogether and wire it so that the central heating position can only happen if the hot water tank is up to temperature. It still does not get the motor out of the situation where it is still running all the time in the CH position with no where to go, but does solve all the problems with the underated micro switches for inductive loads and the motor getting magnetically locked in the mid position (another fault which happens over time). If you are sticking with the original design, then change the 270K resistor to 220k 1W and connect it to the motor from a constant live feed. That way it is constantly being demagnetised even if the boiler is off.

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