This is not a fault I've experienced before and wonder if anyone can give me a few pointers to start off. The burner lights up and runs for a minute or so and then goes off for a few seconds and then relights and so on. I suspect something is detecting a certain temperature level and cutting the burner out. Clearly this not an ideal time of year to have these type of issues!
Biasi Prisma 28se keeps going on and off
- Thread starter tazman
- Start date
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Then again, unlikely to have heating problems in summer. If it is on heating only and dhw is okay, try this:
If the board is similar to the 28 s, dipswitch 4 needs to be on
Thanks for that Bengasman but the problem exists across DHW and CH.
I'm not sure about the switch status you mention but nothing has been done to have altered it.
Reading the Biasi service manual it mentions the following which I'll list with some checks I've carried out:
Flue pipes : I've checked these and they're quite clear.
Pump : Working fine.
CH circuit: I'm not certain what this refers to and hope it means that the CH circuit is not blocked etc
Gas valve modureg: Not sure how to check this as presumably the voltage to it is controlled by the main electronic control board.
Main circuit flow switch: checked and okay.
Fan and venturi device : The fan certainly sounds like it's running without any obvious problems Ie no squealing etc.
I am an engineer of 20 odd years experience in industry around many kinds of machinery including limited experience on Dravo space heaters and the like.
All help greatly appreciated.
I'm not sure about the switch status you mention but nothing has been done to have altered it.
Reading the Biasi service manual it mentions the following which I'll list with some checks I've carried out:
Flue pipes : I've checked these and they're quite clear.
Pump : Working fine.
CH circuit: I'm not certain what this refers to and hope it means that the CH circuit is not blocked etc
Gas valve modureg: Not sure how to check this as presumably the voltage to it is controlled by the main electronic control board.
Main circuit flow switch: checked and okay.
Fan and venturi device : The fan certainly sounds like it's running without any obvious problems Ie no squealing etc.
I am an engineer of 20 odd years experience in industry around many kinds of machinery including limited experience on Dravo space heaters and the like.
All help greatly appreciated.
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The DIP switch 4 is for the anti cycle delay!
It should be in the OFF position with the delay ENABLED for normal running.
Whilst the OP may have lots of experience in other fields but gas is rather different and In view of the safety issues I am not going to risk giving detailed advice unless I thought that he was very competent with gas matters ( in which case he would not need to ask these questions ).
Tony
Its almost certainly a fan/venturi/aps issue. I know exactly what but cannot be specific as I dont encourage a non CORGI to mess with gas or safety issues.
There is no secret that the DIP 4 is the anticycling disable switch. But it should be "off" or "up" to put it in the enabled position.
Tony
There is no secret that the DIP 4 is the anticycling disable switch. But it should be "off" or "up" to put it in the enabled position.
Tony
thought "up" was "on", as this enables the delay. my reasoning seems to be flawed, maybe my oestrogen levels are a bit high.
thought "up" was "on", as this enables the delay. my reasoning seems to be flawed, maybe my oestrogen levels are a bit high.
Well, yes, electrically it is! And practically it is as well!
But when you said it should be "on" then I interpreted that as the common usage in the UK of a switch being "down" to be on!
To clarify, with the boiler the right way up! the switches should all be "UP" to be in the normal operating condition with the anticycle delay operating.
Tony
Hi and thanks for the replies.
Came home from work at lunchtime to be told runs for a while on DHW and actually locks out. I've ran a hot tap and the temp gauge went up to around 70 deg before it locked out with the red light on.
I remember reading previous posts yesterday that said this was due to a blocked up heat exchanger and wonder if anyone can advise me on what to clean it out with once I've removed it.
Thanks once again.
Came home from work at lunchtime to be told runs for a while on DHW and actually locks out. I've ran a hot tap and the temp gauge went up to around 70 deg before it locked out with the red light on.
I remember reading previous posts yesterday that said this was due to a blocked up heat exchanger and wonder if anyone can advise me on what to clean it out with once I've removed it.
Thanks once again.
Well, such is the nature of intermittent machinery faults!!
Ran a hot tap first thing this morning and the boiler fired up and stayed on. Switched the CH on and it carried on working too.
I'm in a real quandry now. Should I have this problem investigated further although that may not be too successful as there is no fault at present?
Anyway thanks to all the very helpful contributors.
Ran a hot tap first thing this morning and the boiler fired up and stayed on. Switched the CH on and it carried on working too.
I'm in a real quandry now. Should I have this problem investigated further although that may not be too successful as there is no fault at present?
Anyway thanks to all the very helpful contributors.
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