Potterton Suprima 50 Lock Out problem
Johnhowell
Posts: 692 Forumite
I have a two up two down end of terrace house fitted with a Potterton Suprima 50 wall mounted fan assisted balanced flue gas boiler on a pumped central heating system with two zone valves.
For sometime now the boiler lockouts with the pump constantly running and the red LED flashing (2 per second). I press the reset button and the boiler lights up and runs fines. Lockout usually happens when I am away, so I come home to a cold house and the sound of the pump running. I have never been able to determine what trips the system. The boiler seems to light and run fine for days on end, until a trip and reset. Sometimes over a weekend it could trip out several times.
The Temperature Control on the boiler is set about midway, the storage tank is set to 60F, and room thermostat is usually set to 21C but reduced whilst away.
Any ideas?
Regards,
John
For sometime now the boiler lockouts with the pump constantly running and the red LED flashing (2 per second). I press the reset button and the boiler lights up and runs fines. Lockout usually happens when I am away, so I come home to a cold house and the sound of the pump running. I have never been able to determine what trips the system. The boiler seems to light and run fine for days on end, until a trip and reset. Sometimes over a weekend it could trip out several times.
The Temperature Control on the boiler is set about midway, the storage tank is set to 60F, and room thermostat is usually set to 21C but reduced whilst away.
Any ideas?
Regards,
John
0
Comments
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Your model of boiler often needs a PCB replacing for this sort of fault. In fact i've lost count how many times i've read it being the case.
If it does need a new PCB expect it to be a few hundred quid supplied and fitted.
If you have newsgroup access try posting at uk.d-i-y for some very well informed replies.0 -
If it locks out in the morning it may be the spark electrode that gets damp overnight if it has a hairline crack in it, it will usually recover once it has some voltage put through it, hence it lighting on the second attempt, and sometimes the gas control valve sticks. If it is overheating then I would usually check the system and bypass first, and I would replace the overheat and boiler stat sensors before shelling out for a costly pcb.0
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Absolutly agree.
Two bloody circut boards went on mine.Second time I was wise to it and it was insured time the engineer was called out(lucky eh?).
Its cheaper to take out a years cover plan from Norwich union or such like,but you have to wait 30 days before making a claim,a swine at this time of year but at least with this you can press the reset button to fire it up again.
They are now being replaced with a new type of PCB which hopefully will stop this fault.RedOnRed wrote:Your model of boiler often needs a PCB replacing for this sort of fault. In fact i've lost count how many times i've read it being the case.
If it does need a new PCB expect it to be a few hundred quid supplied and fitted.
If you have newsgroup access try posting at uk.d-i-y for some very well informed replies.0 -
Thanks for the replies;
RedonRed,
Downloaded the newsgroup messages - only a couple on boilers as present. One states 99/100 its the PCB then another states 99/100 its the temp sensor!
moneysavingplumber,
It has never failed to fire - during the early morning I can hear it fire up readily. I think I am losing sleep due to the noise of the fan starting up and then igniting
What is the procedure/signs for checking the system and bypass? No water is overflowing in the loft header tank.
I assume the pipework will have to be drained down to replace the Temperature Sensor and the Overheat Thermostat, or do they reside in a housing?
Many regards,
John0 -
paulie558 wrote:Absolutly agree.
Two bloody circut boards went on mine.Second time I was wise to it and it was insured time the engineer was called out(lucky eh?).
Its cheaper to take out a years cover plan from Norwich union or such like,but you have to wait 30 days before making a claim,a swine at this time of year but at least with this you can press the reset button to fire it up again.
They are now being replaced with a new type of PCB which hopefully will stop this fault.
Paulie,
So, you went straight for replacing the PCB or did they replace the sensors? - did the engineer run through a test routine on the circuit first?
Typically, I have just thrown away Pottertons Service offer - £183 for one year!
Found the replacement Potterton PCB on MJTControls website at £155+VAT, the two sensors are £5 and £7!
John0 -
Yes,they checked sensors and ran through tests both times.0
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We had exactly the same problem and had to have a new PCB (Printed Circuit Board) fitted. The Corgi guy who fitted it says they are well known for going wrong, so much so he has stocked up on the boards for over the next few weeks.
Incidentally since fitting the new PCB it has never (touch wood) happened since.
It did cost nearly £300 to be supplied and fitted.0 -
Johnhowell wrote:Thanks for the replies;
RedonRed,
Downloaded the newsgroup messages - only a couple on boilers as present. One states 99/100 its the PCB then another states 99/100 its the temp sensor!
moneysavingplumber,
It has never failed to fire - during the early morning I can hear it fire up readily. I think I am losing sleep due to the noise of the fan starting up and then igniting
What is the procedure/signs for checking the system and bypass? No water is overflowing in the loft header tank.
I assume the pipework will have to be drained down to replace the Temperature Sensor and the Overheat Thermostat, or do they reside in a housing?
Many regards,
John
The sensors would have to be changed by a Corgi registered person if it were necessary, but it isn't a drain down job. The by-pass would be checked by checking that you have one for a start, and it is usually installed immediately after the pump on the flow and joins the return of the cylinder coil. Checking that it is correctly set (most are preset at 0.2 bar on domestic systems) means assessing the temperature difference between flow and return under all operating conditions, which should ideally be around 80-69 on a Suprima. Any greater difference or an overheating flow may trip the overheat sensor.
Having said all that, it is true that the Suprima PCBs are notoriously unreliable, and notoriously expensive. The only problem with replacing it on a trial and error basis is that no merchant will usually allow you a 'sale or return' basis on these and it's an expensive mistake if it's wrong.0 -
moneysavingplumber wrote:The sensors would have to be changed by a Corgi registered person if it were necessary, but it isn't a drain down job. The by-pass would be checked by checking that you have one for a start, and it is usually installed immediately after the pump on the flow and joins the return of the cylinder coil. Checking that it is correctly set (most are preset at 0.2 bar on domestic systems) means assessing the temperature difference between flow and return under all operating conditions, which should ideally be around 80-69 on a Suprima. Any greater difference or an overheating flow may trip the overheat sensor.
Having said all that, it is true that the Suprima PCBs are notoriously unreliable, and notoriously expensive. The only problem with replacing it on a trial and error basis is that no merchant will usually allow you a 'sale or return' basis on these and it's an expensive mistake if it's wrong.
There is a bypass pipe after the pump to one of the cylinder pipes, there is an inline valve on this pipe but no pressure gauge.
I assume that a Corgi person has to change the PCB as well?
Regards,
John0 -
Yes it should be a suitably competent person that changes the PCB. In theory it could be an electrician but recommissioning checks would require a Corgi person anyway, to verify that the stats are working correctly and check flame picture etc, although that issue won't be related to the PCB change it's standard procedure to carry out visual checks after carrying out any work on an appliance, as the fitter could be held responsible for any safety issues arising thereafter if they did not carry out the required checks.0
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