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  • FIRST POST
    Johnhowell
    Potterton Suprima 50 Lock Out problem
    • #1
    • 18th Dec 05, 11:27 AM
    Potterton Suprima 50 Lock Out problem 18th Dec 05 at 11:27 AM
    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
Page 1
  • RedOnRed
    • #2
    • 18th Dec 05, 1:15 PM
    • #2
    • 18th Dec 05, 1:15 PM
    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.
  • moneysavingplumber
    • #3
    • 18th Dec 05, 5:38 PM
    • #3
    • 18th Dec 05, 5:38 PM
    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.
  • paulie558
    • #4
    • 18th Dec 05, 6:43 PM
    • #4
    • 18th Dec 05, 6:43 PM
    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.
    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.
    by RedOnRed
  • Johnhowell
    • #5
    • 18th Dec 05, 6:45 PM
    • #5
    • 18th Dec 05, 6:45 PM
    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
  • Johnhowell
    • #6
    • 18th Dec 05, 6:50 PM
    • #6
    • 18th Dec 05, 6:50 PM
    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.
    by paulie558
    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!

    John
  • paulie558
    • #7
    • 18th Dec 05, 8:06 PM
    • #7
    • 18th Dec 05, 8:06 PM
    Yes,they checked sensors and ran through tests both times.
  • dora37
    • #8
    • 18th Dec 05, 8:20 PM
    • #8
    • 18th Dec 05, 8:20 PM
    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.
    Last edited by dora37; 19-12-2005 at 12:05 PM.
  • moneysavingplumber
    • #9
    • 18th Dec 05, 10:15 PM
    • #9
    • 18th Dec 05, 10:15 PM
    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
    by Johnhowell
    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.
  • Johnhowell
    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.
    by moneysavingplumber
    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,
    John
    Last edited by Johnhowell; 19-12-2005 at 5:54 PM.
  • moneysavingplumber
    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.
  • the gasman
    I visit these boilers everyday. Firstly a mate of mine worked for potterton and told me the original suprima pcb with flush grey reset button were faulty and the research and development team set to redsign some of the workings on the board.

    Board 2 was released and had a protruding black reset button. This in my opinion hasn't made them any better and now BOARD 3 is on the shelf. This comes as the complete circuit board wiring harnessand is a sealed unit>(probably so you cant see the resistors burning)and to top it off you have to rewrite the data badge. The board has a self diagnostic indicator built into it,but i dont know whether it will tell you if its the pcb thats broken???

    I have found that the boilers that run with the boiler thermostat on maximum prolong the pcb life.why, i dont know...
    Other than the pcb fault i have only had 1 failed gas valve and 1 seized fan assembly.
    Rule of thumb. IF YOU HAVE TO PRESS THE RESET BUTTON AND IT BECOMES MORE FREQUENT THEN ITS YOUR PCB THATS DYING!!!
    Last edited by the gasman; 21-12-2005 at 1:04 AM.
  • RedOnRed
    It's incredible that a boiler with such a known PCB fault that they don't give the part to the customer for free.

    Any other product would have a product recall. OK, that's impratical for a boiler, but they should at least give out free PCB's for what is a clear design fault.
  • Johnhowell
    gasman,

    The reset button is black and protrudes - so board 2.

    On the MJT Controls website Board 3 is 155 + VAT.

    Does this board 3 have a reset button as well - just in case?

    It does seem to need resetting more frequently - usually at 5am, so a cold rush downstairs to get some heat before the alarm bell goes at 6:45! And when I arrive home after work it is off again!

    Would it be worth getting the two sensors, at the same time as the PCB, replaced as they are only 5 and 7?

    Any idea how much labour would be changed for these three items? I think I shall be phoning around after the holiday.

    Many thanks,
    John
  • fsdss
    can i just say that we recently called out potterton at a cost of 250 to mend the boiler with similar prob and yes he replaced the pcb board. however we were told that if we took out the years insurance for the boiler (about 150) they would do it for free...one snag.....just dont tell them that the boiler is on the blink to start with.......this advice came from the engineer who attended our house.

    potterton were excellent i must add they came out within a couple of days and on time!!!
  • the gasman
    gasman,

    The reset button is black and protrudes - so board 2.

    On the MJT Controls website Board 3 is 155 + VAT.

    Does this board 3 have a reset button as well - just in case?

    It does seem to need resetting more frequently - usually at 5am, so a cold rush downstairs to get some heat before the alarm bell goes at 6:45! And when I arrive home after work it is off again!

    Would it be worth getting the two sensors, at the same time as the PCB, replaced as they are only 5 and 7?

    Any idea how much labour would be changed for these three items? I think I shall be phoning around after the holiday.

    Many thanks,
    John
    by Johnhowell
    Hi john.
    The latest pcb for the suprima comes complete with a wiring harness. Yes it does have a slightly smaller black reset button than board 2 and i think its square. Your current pcb should have 2 lights (red and green).
    The new board has just one, but it has a led which flashes several colours dependant on what mode the boiler is at...
    The price seems reasonable at 155. (Potterton do know how to charge)
    I have never had to change the sensors at the same time. It has always only been the pcb. The thermistors and overheat stats are pretty reliable, but the choice is yours.

    The first pcb (board 3) that i fitted took 1 1/2 hrs to fit. I now fit them in around 40 mins, but i fit at least 3 per week this time of year. I would suggest an hours labour be reasonable.
    good luck

    the gasman
  • keithwjones
    I've got a Suprima 80 - with grey reset button - exactly the same problem.

    Boiler about 5 years old. Looks like I've found the answer.

    Keith
  • RedOnRed
    however we were told that if we took out the years insurance for the boiler (about 150) they would do it for free.
    by fsdss
    Why not pay the same sort of amount to British Gas and have your whole system and boiler covered?
  • Johnhowell
    Called a CORGI engineer yesterday and he was aware of the PCB problem and he came around last night and "just so happened" to have a replacement with him!

    Fitted for 300 all in.

    Seems to be working OK - now I can get some sleep without worrying whether the boiler Locks Out

    Many thanks everyone,

    John
  • Jolie Madame
    This reply might be too late to help you , but it might well help others. Having been quoted £300 to sort the lockout problems on our Potterton Suprima, we found 'compumerv' on eBay and bought a service exchange PCB ;helpful advice and cost £35 including the post and packing. Fitted in 5 minutes and has cured the boiler.
    Hope this helps.
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