Puma 100 issues

[Frustrated Puma User]

Afternoon folks.

I am back once again with a Puma problem!

I won't be carrying out any work as my landlord has an excellent gas engineer, but I like to find out what the cause(s) of the problems are with my boiler so that I can ensure the engineer addresses the correct areas. (My landlord often will instruct tradespersons to employ a safe, but temporary workaround instead of a long-term fix if a long-term fix would be expensive (such as major part replacement).

So the issue is this:

Around three months ago the boiler was losing system pressure every evening (going below 0.5 bar and illuminating the Low System Pressure light). I had to recharge every morning. After two weeks of this, the pressure stabilised and the issue stopped happening.

About 8 weeks ago the boiler was running as normal with CH and HW all OK, until I heard very loud noises (imagine the sound of a large, seized spring being stretched) and a LOT of deep gurgling sounds coming from the boiler. (Sometimes I worry as it sounds like the pressure vessel is going to explode)! I have heard these a few times since then, although two days ago when it happened the auto air vent discharged and the burner went out. I attempted to relight the boiler but when I release the gas control knob the pilot extinguishes immediately. I believe that the thermocouple needs to be replaced as I had this problem once in the past and the 'workaround' used to remedy it was to unscrew the thermocouple and re-route it through the front of the chamber push it into closer contact with the pilot flame.

I think the thermocouple has reached the end of its life and needs replacing. Would you agree and if so, do you thnk that this will resolve the problem?

Also, since the issue two days ago the DHW LED remains lit for upto 60 secs+ after turning off the HW tap. The spring and piston in the DHW flow switch appears to be sticking. (I have only noticed this since the boiler stopped working, and therefore I have only been able to test it with the boiler off).

I would prefer a new boiler but I don't think I am going to get one.

All thoughts and advice will be greatly appreciated.

Kind regards,

Gaz

 

[steve32]

I think the thermocouple has reached the end of its life and needs replacing. Would you agree and if so, do you thnk that this will resolve the problem?

No this fault is not the thermocoupling

 

[Frustrated Puma User]

Ah, it's just that my landlord advised me he was going to get the thermocouple replaced as he thinks it's that. (As the last time he had an engineer visit he said it was going and hence used the 'workaround' described above). As yet, I've got home from work and no-one's been yet. Sitting with an electric heater in one room!

 

[steve32]

the combi has overheated and gone to lockout i would be checking the hw flow valve and checking the diverter valve.
now that it's cooled down you should be able to relight the pilot.

 

[gazthepottertonengineer]

Sounds to me like a sticking microswitch 21/18867

 

[Frustrated Puma User]

Thanks for your replies so far. I'll keep my eye on that microswitch. The PCB was replaced with a reconditioned one about a year and a half ago as the old one burnt out (top left as usual). The currently fited recon PCB had dry solder on the same area and was resoldered about a month after fitting. Then almost a year ago, a new pump was fitted when the old one packed up. the other known issue with my boiler is that he PRV is slowly letting by and has always done so since a discharge several years ago.

I've had word that the engineer is coming tomorow. In the meantme however, I have managed to light the boiler!

I turned a HW tap on and off repeatedly many tmes The DHW LED now only stays on for 6 secs instead of 60 after turning off a HW tap (this was done whilst the boiler was still off and unlit).

I managed to get the boiler to light by releasing the gas control knob fairly quickly, but only after I turned the boiler from Standby to On, and set the CH to Constant, and waited around 20 seconds before releasing the control knob. Then the burner lit as expected when I turned the control knob to Full Flame. So for now, it seems to be working again!