potterton puma 80 ?overheating problems
- Thread starter muppster
- Start date
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In the situation you describe gazdaz36 then you've assumed the demand for dhw has stopped and it's back in ch mode, the wax capsule hasn't returned so the burner keeps firing until overheat. Well sparky the lack of dhw demand brings the primary thermistor into the equasion and when the heat has accumulated in the primary circuit the thermistor shuts off the gas until colder water is introduced, like say for instance the wax capsule moving into the ch position. If the wax capsule does not move into the ch position then the pump will carry on running and when primary water cools the boiler will fire and the sequence will start again. Never resulting in an overheat. If however the dhw demand hasn't stopped then the primary thermistor won't be a factor because the boiler is measuring temp from the dhw thermistor which means it won't shut down the gas and the result is...........you guessed it, overheat.
I suspect the "36" in your username is actually your IQ.
Oh yeah, working for BG for 15 years is about as good an endorsement as saying "course I can mend your boiler, I was a park keeper for 15 years"
I suspect the "36" in your username is actually your IQ.
Oh yeah, working for BG for 15 years is about as good an endorsement as saying "course I can mend your boiler, I was a park keeper for 15 years"
Or the CH sensor is not working and fails to modulate the boiler back until the diverter valve has opened.
He must be a "parts changer" who has no understanding of how boilers work.
I have never had any need or wish to work for British Gas. I think I would find it a little boring and might upset the engineers when I have to show them how they should be doing the job.
Tony
He must be a "parts changer" who has no understanding of how boilers work.
I have never had any need or wish to work for British Gas. I think I would find it a little boring and might upset the engineers when I have to show them how they should be doing the job.
Tony
Cheers for all your comments guys - plus am loving the arguing - makes for entertaining reading!!!
It seems that this is not a well known common fault that everyone agrees on! (I know the flowswitch sticking is - but this is definitely not at fault as the red light goes off the second the tap does) As I said the boiler never fails if the heating is off, and with heating on, it only fails after the tap is turned off having been on for ages, and just quietly shuts off!
Will look into some of the ideas posted on here - but to be honest it seems like if I just turn off the heating to run a bath - I have no problems!
It seems that this is not a well known common fault that everyone agrees on! (I know the flowswitch sticking is - but this is definitely not at fault as the red light goes off the second the tap does) As I said the boiler never fails if the heating is off, and with heating on, it only fails after the tap is turned off having been on for ages, and just quietly shuts off!
Will look into some of the ideas posted on here - but to be honest it seems like if I just turn off the heating to run a bath - I have no problems!
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if the red light goes out as soon as the tap is turned off then you can disregard my first post. Something else to look at based on your desriptions is that the heat exchanger needs the fins cleaning. If the spaces between the fins are restricted with debris then the heat from the flames is partially dampered back into the part of the combustion chamber where incoming air whould normally be prominent. This can cause pilot failure in 2 ways.
1. the heat within that part of the chamber becomes so intense that it operates the safety stat by air temp instead of water temp.
2. the build up of CO2 in place of incoming oxygen simply suffocates the pilot so what might seem to be an overheat isn't but the result is the same....pilot out.
Oh and the arguing, well it takes the boredom out of it. I suspect that gazdaz36 is actually a well established member logging in under an alias as a wind up
1. the heat within that part of the chamber becomes so intense that it operates the safety stat by air temp instead of water temp.
2. the build up of CO2 in place of incoming oxygen simply suffocates the pilot so what might seem to be an overheat isn't but the result is the same....pilot out.
Oh and the arguing, well it takes the boredom out of it. I suspect that gazdaz36 is actually a well established member logging in under an alias as a wind up
Dr Drivel?
On this boiler, does the pump run as soon as red light (HW demand) is made? I would have thought the pump should start spinning as soon as demand is made
Have same defect on another Puma 80. Sequence seems to suggest there is a lag before pump runs. Pink (live to pump) goes live following a click (a relay operates) few seconds after the fan is running and burner is already on. Above click also keeps the pump running after the demand is satisfied.
Any ideas? I suspect pump non run is the culprit.
Have same defect on another Puma 80. Sequence seems to suggest there is a lag before pump runs. Pink (live to pump) goes live following a click (a relay operates) few seconds after the fan is running and burner is already on. Above click also keeps the pump running after the demand is satisfied.
Any ideas? I suspect pump non run is the culprit.
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