G
gtmspyder
Good morning gentlemen.
I have a Saunier Duval boiler with lock out problems.
It has 3 micro-switches, two of which are operated by a spring loaded water operated diaphragm bellows which pushes a stainless pin out to impinge onto a clip on micro switch to actuate it.
1)Domestic hot water flow, (part No802299) this switches the boiler from heating demand to DHW.
2)Pressure differential switch, (Part No801189) who's micro switch is in series with the boiler cut off switch and locks out the boiler if the pin retracts due to a loss of pressure.
3)Water pressur switch, (Part No 227099 ammended)) which is marked on the instructions I have as "low water ressure switch".
I have in the past, a long time ago, changed switch 3, and it has given me no further trouble.
Switches 1 and 2 , have regularly played up with either the micro switch failing, or the rubber membrane in the water operated bellows assembly failing.
I have just changed the bellows and micro switch on switch 1, as the stainless pin was sticking and not returning to heating mode when the tap was turned off
I have yet to service switch 2 as the pin of that bellows unit is stuck in the pushed out micro switch operating position , but ran out of time due to other commitments, as this requires draining part of the heating system down to drain the bellows.
What is puzzling me, and my quesion is, the 3rd switch, (Part No227099 ammended), if that is the low water micro switch, and one presumes will shut down the boiler, why is switch 2 also doing the same thing with a loss of water?
Co incidentally, switches 1 and 2 are interchangeable, I know the Domestic hot water switch (1) has three wires and the pressure differential (2) has two, but the red wire of switch one does nothing.
Also strangely, I have to use Pumb Centre, (Yes I know they are crap and overcharge, but that is my local supplier and I no longer have access to trade prices) but the price they charge for the 3 wire micro switch is £3 plus vat cheaper than the 2 wire switch, how crazy is that???
A little history to put your minds at ease.
I am a 74 year old retired hospital engineer of thirty years standing, I did attend an old Corgi course with my fitters at the time, because I have always believed I should be able to do whatever I ask any of my staff to do. I am an electrical and mechanical engineer and had many boilers under my jurisdiction from tiddly domestic boilers in the many staff houses upto 20,000 lbs/hr steam raising boilers fired by gas, oil and solid fuel during my tenency of that position.
Thanking you for your time in reading this.
Kind regards,
BrianT.
I have a Saunier Duval boiler with lock out problems.
It has 3 micro-switches, two of which are operated by a spring loaded water operated diaphragm bellows which pushes a stainless pin out to impinge onto a clip on micro switch to actuate it.
1)Domestic hot water flow, (part No802299) this switches the boiler from heating demand to DHW.
2)Pressure differential switch, (Part No801189) who's micro switch is in series with the boiler cut off switch and locks out the boiler if the pin retracts due to a loss of pressure.
3)Water pressur switch, (Part No 227099 ammended)) which is marked on the instructions I have as "low water ressure switch".
I have in the past, a long time ago, changed switch 3, and it has given me no further trouble.
Switches 1 and 2 , have regularly played up with either the micro switch failing, or the rubber membrane in the water operated bellows assembly failing.
I have just changed the bellows and micro switch on switch 1, as the stainless pin was sticking and not returning to heating mode when the tap was turned off
I have yet to service switch 2 as the pin of that bellows unit is stuck in the pushed out micro switch operating position , but ran out of time due to other commitments, as this requires draining part of the heating system down to drain the bellows.
What is puzzling me, and my quesion is, the 3rd switch, (Part No227099 ammended), if that is the low water micro switch, and one presumes will shut down the boiler, why is switch 2 also doing the same thing with a loss of water?
Co incidentally, switches 1 and 2 are interchangeable, I know the Domestic hot water switch (1) has three wires and the pressure differential (2) has two, but the red wire of switch one does nothing.
Also strangely, I have to use Pumb Centre, (Yes I know they are crap and overcharge, but that is my local supplier and I no longer have access to trade prices) but the price they charge for the 3 wire micro switch is £3 plus vat cheaper than the 2 wire switch, how crazy is that???
A little history to put your minds at ease.
I am a 74 year old retired hospital engineer of thirty years standing, I did attend an old Corgi course with my fitters at the time, because I have always believed I should be able to do whatever I ask any of my staff to do. I am an electrical and mechanical engineer and had many boilers under my jurisdiction from tiddly domestic boilers in the many staff houses upto 20,000 lbs/hr steam raising boilers fired by gas, oil and solid fuel during my tenency of that position.
Thanking you for your time in reading this.
Kind regards,
BrianT.