Potterton Puma 80 clickin noise = flow switch?

[Jordi]

Hi,

My Puma 80 makes clicking noise as if attempting to fire ie: starts sequence when I turn off cold water tap. The noise sounds just like the gas valve opening and closing. On some occasion I think it may have even fired for a brief second. It always does this it is just the length that varies mabe from a second to 3 secs. However if I turn of the tap slowly over 2 - 3 seconds than it does not click. I tried to adjust the micro switch and when finally got it to stop the micro switch was too far out for the boiler to fire when hot water is called for. Tried to fiddle the correct adjustment but could not stop it clicking on cold water tap being turned off. I put another microswitch (second hand from working boiler) but it did the same. Everything else seems to work fine on heating and water.
Could it be the flow switch itself or what could it be I wander?

Any ideas and suggestions how to remedy the fault please as it probably waste quite a bit of gas and will wear out the gas valve prematurely or cause some other fault.

Many thanks

Jordi

 

[Agile]

The internal diaphragm may be failing or the pin is stiff and needs cleaning and lubricating.

At rest there should be about a 1 mm air gap.

Tony Glazier

 

[Beerlover]

Most likely caused by a dead leg in your pipework or possibly pipe hammer, a plumber will be able to check for these easily. There is a little white expansion vessel (shock arrestor) on your boiler which helps stop this - it may be flat or need replacing.

 

[Jordi]

The internal diaphragm may be failing or the pin is stiff and needs cleaning and lubricating.

At rest there should be about a 1 mm air gap.

Tony Glazier

Hi Tony, Thank you for your super speed reply. Do you mean the little pin sticking out from the flow switch (about 3mm) or the pin from the microswitch.The air gap seems correct . The pin from the flow switch is not moving on say 3-5 kg pressure. The one on microswitch is moving and clicking easily. As you said looks like the diaphragm is the problem.

 

[Jordi]

Most likely caused by a dead leg in your pipework or possibly pipe hammer, a plumber will be able to check for these easily. There is a little white expansion vessel (shock arrestor) on your boiler which helps stop this - it may be flat or need replacing.

Hi Beerlover, thank you for your insights, there was watter hammer (pipe hammer effect) in the instalation for the last several years. Now I cannot hear it because boiler makes the sequential noise (fan, gas valve etc.) but I am sure it is still there. Do you mean the DHW expansion vessel (siver collour looking little thing at the back by the wall) as I cannot see any other?

Cheers for now.

Jordi

 

[Beerlover]

Most likely caused by a dead leg in your pipework or possibly pipe hammer, a plumber will be able to check for these easily. There is a little white expansion vessel (shock arrestor) on your boiler which helps stop this - it may be flat or need replacing.

Hi Beerlover, thank you for your insights, there was watter hammer (pipe hammer effect) in the instalation for the last several years. Now I cannot hear it because boiler makes the sequential noise (fan, gas valve etc.) but I am sure it is still there. Do you mean the DHW expansion vessel (siver collour looking little thing at the back by the wall) as I cannot see any other?

Cheers for now.

Jordi

Yeah that's the one

 

[Agile]

The movement of the pin is described by the DHW flow rate.

Fully out for less that 3 litres/minute.

The pin from the diaphragm unit should move freely. Many are dirty and need cleaning and lubricating.

Tony Glazier

 

[Jordi]

The movement of the pin is described by the DHW flow rate.

Fully out for less that 3 litres/minute.

The pin from the diaphragm unit should move freely. Many are dirty and need cleaning and lubricating.

Tony Glazier

Tony, thank you very much for your time & teachings. I squirted wd40 and moved it a bit in & out thinking it must have some kind of head like a nail inside so it cannot pop out. But i did with the gush of watter. Luckily I had portected the PCB thorougly and it landed within reach so I plugged it quickly back. No leak so far after the event. Great learning experience will not pull on it again in a million years.
Just recalled whe refurbishing my kitchen I did not mack about with pipes much so left them as they were. Now I refered to some photos and found that there is a dead leg (actually 2 stubbs of the main pipes just cupped off where the previous sink was , hence the watter hammer i heard before). Now some little disturbance or change in preassure may have worsened it which results in boiler going trhough the strange motion. there may not be any problems with the boiler itself. Will have to see if the sink coubportd can be moved to try and cut the thing off and leave completely straight pipes fo eliminate dead legs. Someone said single non return valve on cold water just befor boiler can eliminate the boiler attempting to fire on closing the cold watter tap. Will eventualy when all finished post my findings hopefully with a good results.

Once again your help is very much apreciated.

J

 

[Agile]

To remove the pin to clean you need to turn off mains water!

Tony

 

[Jordi]

To remove the pin to clean you need to turn off mains water!

Tony

Thank you Tony, I should have been a bit more cautions or thoughtfull - lesson leraned, this will stick with me for a long time.

 

[thanksmate]

To remove the pin to clean you need to turn off mains water!

Tony

I just wanted to tell you what a hero you are Tony. This solution worked for me big time on a Puma 100. I took your advice & removed the rounded sort of nut just behind the DHW flow switch after turning off mains of course.
Not really too much gunk but pin had limescale at the root which stopped the switch from being fully depressed. I soaked it in descaler for an hour, rinsed it off, put on a little silicone grease you recommended elsewhere, replaced the O ring and bingo... new boiler. You're a genius mate & saved me hundreds and I've never been so skint, unemployed etc.
My symptoms were pilot light going out a lot (lock out) when HW used same time as CH, lots of strange noises, flow intermittent, CH hardly working & occasionally CH & HW not even working at all. This is just the type of problem that a pro would've charged me a fortune for cos even he probably wouldn't have known either.
Lastly, another very warm & heartfelt thanks from me mate you are a top bloke to me and my family - big thanks from them too!

 

[gaswizzard]

Tony is that you? (thanksmate)

 

[nebs]

Not sure if it is relevant, but I have the same boiler. The thing used to go mad, clicking like a machine gun.

My boiler engineer took a look at the circuit board. There were some dry contacts, so with a bit of solder, the contacts were sorted and the clicking stopped.

 

[Jordi]

Beerlover you were spot on. A couple of months ago I was determined to sort it out and found the dead leg behind washing machine. When new washing machine was installed it did not need to be connected to the hot water but the pipe work remained. Once the pipes wore drained did not get filled up completely again so upon closing the kitchen the pressure was causing some movement and it was tricking the boiler as if there was the demand for hot water. Removal of the dead leg sorted it all out.

At the same time I did clean the pin on the flow switch and the clicking noise while the boiler was fired up in CH mode ( this was happening as well fairly frequently) disappeared as well. I guess the pin was not returning fully to the off position.

So my massive thanks to Beerlover And Tony = Agile for sharing your time and knowledge.

Hopefully this reply and conformation of the problem resolution may help someone in the same or similar situation.

Jordan

 

[Agile]

This is just the type of problem that a pro would've charged me a fortune for cos even he probably wouldn't have known either.

Lastly, another very warm & heartfelt thanks from me mate you are a top bloke to me and my family - big thanks from them too!

Nice words there!

One time I repaired that fault for just my normal diagnostic fee the "nice" customer did not pay me! So much for his thanks!