Just replaced the leaky heat exchanger in my Potterton Suprima 100.  It 
took approx 4 weeks what with HRPC ordering the wrong parts repeatedly 
but we managed it OK in the end.

Boiler sparked up fine for about a week but has now adopted the 
following mode of operation. viz: Power on, boiler stat set to maximum 
and tank calling for heat: fan starts running followed by ignition 
sparks followed by no gas and blinking red LED.

Am I right in thinking that this is the infamous 'lockout problem'?   I 
can't remember if these are symptoms that, about 2 years ago, prompted 
me to re-solder every joint on the PCB.  This cured the fault that I was 
experiencing at that time.

I can't believe that this failure is coincidental with replacing the 
heat exchanger but the only disturbance suffered by the PCB was the 
tilting of it's carrier to give access to the heat ex mounting bolts.

TIA

Richard

-- 
Real email address is RJSavage at BIGFOOT dot COM

"rjs"  wrote in message
news:cfGdnZ2dnZ1X8xe8nZ2dncIRvN6dnZ2dRVnypZ2dnZ0@pipex.net...

> Just replaced the leaky heat exchanger in my Potterton Suprima 100.  It
> took approx 4 weeks what with HRPC ordering the wrong parts repeatedly
> but we managed it OK in the end.
>
> Boiler sparked up fine for about a week but has now adopted the
> following mode of operation. viz: Power on, boiler stat set to maximum
> and tank calling for heat: fan starts running followed by ignition
> sparks followed by no gas and blinking red LED.
>
> Am I right in thinking that this is the infamous 'lockout problem'?   I
> can't remember if these are symptoms that, about 2 years ago, prompted
> me to re-solder every joint on the PCB.  This cured the fault that I was
> experiencing at that time.
>
> I can't believe that this failure is coincidental with replacing the
> heat exchanger but the only disturbance suffered by the PCB was the
> tilting of it's carrier to give access to the heat ex mounting bolts.
>
> TIA
>
> Richard


Do you get a brief burn, followed by shutdown? If so, check the spark gap,
as this is used as a flame sensor as well, and if only marginally too wide
gives a "no flame" reading, leading to shutdown. If this is the case then
the boiler has another couple of attempts and then locks out. My suprima is
quite fussy, and only works if the spark gap is on the minimum gap spec.

Lovely boilers!

Charles

Charles Fearnley wrote:


>>Richard
> 
> 
> Do you get a brief burn, followed by shutdown? If so, check the spark gap,
> as this is used as a flame sensor as well, and if only marginally too wide
> gives a "no flame" reading, leading to shutdown. If this is the case then
> the boiler has another couple of attempts and then locks out. My suprima is
> quite fussy, and only works if the spark gap is on the minimum gap spec.
> 
> Lovely boilers!
> 
> Charles
> 
> 


Charles

No burn at all now.  I'll try the spark gap adjustment.  As I said it 
/did/ run OK for the week post-heat exch replacement, which is why I 
fear that it's just an awful coincidence and the *********** PCB has 
given up (again).

I did wonder if the pressure switch air hose had developed a leak and 
tried disconnecting it and blowing/sucking into it.  That allowed the 
boiler to light sans cover - very 'exciting'.  I was so encouraged by 
this that I replaced the hose whilst the fan was still spinning - a less 
than good idea but I did manage to find the Steristrips fairly quickly!!

However, now it attemps to start (fan + ignition sequence) and then faults.

Richard
-- 
Real email address is RJSavage at BIGFOOT dot COM

In message , rjs 
 writes

>Just replaced the leaky heat exchanger in my Potterton Suprima 100.  It 
>took approx 4 weeks what with HRPC ordering the wrong parts repeatedly 
>but we managed it OK in the end.
>
>Boiler sparked up fine for about a week but has now adopted the 
>following mode of operation. viz: Power on, boiler stat set to maximum 
>and tank calling for heat: fan starts running followed by ignition 
>sparks followed by no gas and blinking red LED.


Well, is the pcb actually powering the gas valve solenoid ?

(It should be about 230v DC (not AC) and ignore the voltage quoted in 
the manual of 300+ volts)


>
>Am I right in thinking that this is the infamous 'lockout problem'?   I 
>can't remember if these are symptoms that, about 2 years ago, prompted 
>me to re-solder every joint on the PCB.  This cured the fault that I 
>was experiencing at that time.
>
>I can't believe that this failure is coincidental with replacing the 
>heat exchanger but the only disturbance suffered by the PCB was the 
>tilting of it's carrier to give access to the heat ex mounting bolts.
>
>TIA
>
>Richard
>


-- 
geoff

In message , rjs 
 writes

>Charles Fearnley wrote:
>
>>>Richard
>>   Do you get a brief burn, followed by shutdown? If so, check the 
>>spark gap,
>> as this is used as a flame sensor as well, and if only marginally too wide
>> gives a "no flame" reading, leading to shutdown. If this is the case then
>> the boiler has another couple of attempts and then locks out. My suprima is
>> quite fussy, and only works if the spark gap is on the minimum gap spec.
>>  Lovely boilers!
>>  Charles
>>
>
>Charles
>
>No burn at all now.  I'll try the spark gap adjustment.  As I said it 
>/did/ run OK for the week post-heat exch replacement, which is why I 
>fear that it's just an awful coincidence and the *********** PCB has 
>given up (again).
>
>I did wonder if the pressure switch air hose had developed a leak and 
>tried disconnecting it and blowing/sucking into it.


It shouldn't be the fault if the board is creating a spark. For the 
board to spark, the APS has already indicated to the pcb that the fan is 
working


>That allowed the boiler to light sans cover - very 'exciting'.  I was 
>so encouraged by this that I replaced the hose whilst the fan was still 
>spinning - a less than good idea but I did manage to find the 
>Steristrips fairly quickly!!
>
>However, now it attemps to start (fan + ignition sequence) and then faults.


What, it actually lights the gas ?


-- 
geoff

raden wrote:

> In message , rjs 
>  writes
> 
> 
> 
> Well, is the pcb actually powering the gas valve solenoid ?
> 
> (It should be about 230v DC (not AC) and ignore the voltage quoted in 
> the manual of 300+ volts)
> 
>>
>> 
>>
> 

Thanks Geoff

I'll check voltages presently - probably not today as I'm supposed to be 
taking SWMBO away for a short break.   Gas /was/ lighting until my first 
post, i.e. a week of satisfactory operation after heat exch replacement.

Gas is now not lighting.  The sequence at power up (with cold h/w 
tank)is : fan runs, a few seconds later the ignition sparks start, then 
fan and sparks stop followed by blinking red LED.

Interesting that the unit seems to remember the state it was in when 
switched off at the mains - i.e. if I switch off in a fault state that's 
how it comes back on.  I naively(?) would have thought that power 
cycling would cause a self test at power up?

<sigh>

Ta

Richard
-- 
Real email address is RJSavage at BIGFOOT dot COM

"rjs"  wrote in message
news:Lq2dnZ2dnZ3KsEPJnZ2dnYdZv96dnZ2dRVny3Z2dnZ0@pipex.net...

> raden wrote:
> > In message , rjs
> >  writes
> >
> >
> >
> > Well, is the pcb actually powering the gas valve solenoid ?
> >
> > (It should be about 230v DC (not AC) and ignore the voltage quoted in
> > the manual of 300+ volts)
> >
> >>
> >>
> >>
> >
> Thanks Geoff
>
> I'll check voltages presently - probably not today as I'm supposed to be
> taking SWMBO away for a short break.   Gas /was/ lighting until my first
> post, i.e. a week of satisfactory operation after heat exch replacement.
>
> Gas is now not lighting.  The sequence at power up (with cold h/w
> tank)is : fan runs, a few seconds later the ignition sparks start, then
> fan and sparks stop followed by blinking red LED.
>
> Interesting that the unit seems to remember the state it was in when
> switched off at the mains - i.e. if I switch off in a fault state that's
> how it comes back on.  I naively(?) would have thought that power
> cycling would cause a self test at power up?
>
> <sigh>
>
> Ta
>
> Richard


That unfortunately does not sound like the spark gap problem I mentioned
earlier - so it does sound as though you have a new/different fault.

I now do not trust my boiler to such an extent that I have added a reset
relay, to be triggered every couple of days in the winter if we are away, to
stop the house freezing. The one good thing about this mod was that there
was a header on the PCB acropss the reset contacts - I wonder why?

Charles

In message , Davide 
 writes

>
>Boiler sparked up fine for about a week but has now adopted the
>following mode of operation. viz: Power on, boiler stat set to maximum
>and tank calling for heat: fan starts running followed by ignition
>sparks followed by no gas and blinking red LED.
>
>I had a similar occurrence on a Baxi SoloPF2 a couple of years ago. The
>solenoid in the gas valve had gone - so check for continuity between 
>the
>two solenoid terminals, as well as for 230 VAC at the solenoid pin on
>the PCB.
>

Wrong

The Suprima gas valve is DC, so measuring on an AC range will give you a 
completely false reading.

The Suprima manual is also a tad inaccurate in that in the fault finding 
you should the 300 and something volts DC from the pcb to the gas valve 
solenoid. You only get this in no load conditions i.e. if the solenoid 
is open circuit, with the solenoid in circuit it's about 220-240vDC

The Suprima pcb is completely different to the Solo 2 and is infamous 
for going into lockout. If you're bored, google for "Suprima lockout 
problem"

-- 
geoff

Boiler sparked up fine for about a week but has now adopted the
following mode of operation. viz: Power on, boiler stat set to maximum
and tank calling for heat: fan starts running followed by ignition
sparks followed by no gas and blinking red LED.

I had a similar occurrence on a Baxi SoloPF2 a couple of years ago. The
solenoid in the gas valve had gone - so check for continuity between the
two solenoid terminals, as well as for 230 VAC at the solenoid pin on
the PCB.

HTH

Davide


-- 
Davide

raden wrote:


> The Suprima gas valve is DC, so measuring on an AC range will give you a 
> completely false reading.
> 
> The Suprima manual is also a tad inaccurate in that in the fault finding 
> you should the 300 and something volts DC from the pcb to the gas valve 
> solenoid. You only get this in no load conditions i.e. if the solenoid 
> is open circuit, with the solenoid in circuit it's about 220-240vDC
> 
> The Suprima pcb is completely different to the Solo 2 and is infamous 
> for going into lockout. If you're bored, google for "Suprima lockout 
> problem"
> 


Hi Geoff

Testing done.  Results are:

Across V1 and V2 (if I can read them correctly - but the red and black 
wires into the solenoid connector):

[1] No external call for heat and boiler stat OFF: 1.?? Vdc

[2] External call for heat and boiler stat set to maximum: a minute 
pulse from the 1.??Vdc during the sparking phase, but which the memory 
of my (Fluke) DVM cannot capture.

Resitance of solenoid across V1 and V2 is 4K ohms.

Interesting to note that even in state [1] there is 250Vdc present 
across the red and black wires of the solenoid connector when _not_ 
connected to the solenoid.

HTH in your much appreciated thoughts.

In my ignorance I was going to guess at a faulty gas valve solenoid but 
am perplexed as to why the high voltage is present even when the boiler 
is not attempting to light.

Rgds

Richard



-- 
Real email address is RJSavage at BIGFOOT dot COM

In message , rjs  
writes

>raden wrote:
>
>> The Suprima gas valve is DC, so measuring on an AC range will give 
>>you a  completely false reading.
>>  The Suprima manual is also a tad inaccurate in that in the fault 
>>finding  you should the 300 and something volts DC from the pcb to the 
>>gas valve  solenoid. You only get this in no load conditions i.e. if 
>>the solenoid  is open circuit, with the solenoid in circuit it's about 
>>220-240vDC
>>  The Suprima pcb is completely different to the Solo 2 and is 
>>infamous  for going into lockout. If you're bored, google for "Suprima 
>>lockout  problem"
>>
>
>Hi Geoff
>
>Testing done.  Results are:
>
>Across V1 and V2 (if I can read them correctly - but the red and black 
>wires into the solenoid connector):
>
>[1] No external call for heat and boiler stat OFF: 1.?? Vdc
>
>[2] External call for heat and boiler stat set to maximum: a minute 
>pulse from the 1.??Vdc during the sparking phase, but which the memory 
>of my (Fluke) DVM cannot capture.
>
>Resitance of solenoid across V1 and V2 is 4K ohms.
>
>Interesting to note that even in state [1] there is 250Vdc present 
>across the red and black wires of the solenoid connector when _not_ 
>connected to the solenoid.
>
>HTH in your much appreciated thoughts.
>
>In my ignorance I was going to guess at a faulty gas valve solenoid but 
>am perplexed as to why the high voltage is present even when the boiler 
>is not attempting to light.
>

Well, you can ignore the volt and a bit - it's prolly just pickup and 
it's not really going to have much of an effect on a solenoid which 
requires 200v+ to work

250vDC - I would have expected more, but it's a fairly pointless 
measurement if it's not connected to a load

4k sounds a reasonable figure - I don't actually know offhand without 
looking

By "no external call for heat, are you saying that you don't have mains 
on the SWL ?

What's the resistance of the temperature sensor ?

-- 
geoff

raden wrote:

> In message , rjs  

>>
> Well, you can ignore the volt and a bit - it's prolly just pickup and 
> it's not really going to have much of an effect on a solenoid which 
> requires 200v+ to work

Agreed

> 
> 250vDC - I would have expected more, but it's a fairly pointless 
> measurement if it's not connected to a load


Also agreed.  I will re-measure it off load tonight.  But should this 
voltage be present all the time, i.e even when the boiler is not 
providing heat?


> 
> 4k sounds a reasonable figure - I don't actually know offhand without 
> looking

Ditto

> 
> By "no external call for heat, are you saying that you don't have mains 
> on the SWL ?


Mains on, timer/controller set to continuous HW and CH but HW tank stat 
set to minimum and temperature control on boiler also set to minimum (or 
rather off).  This is my understanding of one of the steps in the fault 
finding flow chart.   Next step is to increase the tank stat and observe 
the red and green LEDs followed by setting the boiler stat to maximum. 
  At that point the fan starts followed by sparking followed by no(!) gas.

What is 'SWL' an abbreviation of?


> 
> What's the resistance of the temperature sensor ?


Will check tonight.   As it happens, both temp sensor and overheat 
sensor were replaced along with the new heat exchanger a week ago.  I 
had wondered about refitting the originals - maybe I should.


> 


Thanks

Richard
-- 
Real email address is RJSavage at BIGFOOT dot COM

raden wrote:



> Well, you can ignore the volt and a bit - it's prolly just pickup and 
> it's not really going to have much of an effect on a solenoid which 
> requires 200v+ to work
> 
> 250vDC - I would have expected more, but it's a fairly pointless 
> measurement if it's not connected to a load
> 
> 4k sounds a reasonable figure - I don't actually know offhand without 
> looking
> 
> By "no external call for heat, are you saying that you don't have mains 
> on the SWL ?
> 
> What's the resistance of the temperature sensor ?
> 


Hi Geoff

Resistance readings as follows:

Both old and new temperature sensors are 0M95 ohms, decreasing as the 
sensors warm

The old overheat sensor has a resistance of 0R1 to 0R2 ohms.  The new 
overheat sensor has a resistance of 1R3 ohms.  Swopping the overheat 
sensors has no effect on the boiler operation.


I have re-measured the voltage at the plug to the gas valve, i.e. off load:

With Red LED on and Green LED blinking slowly (Potterton descibe it as 
2Hz but 0.5Hz is more accurate) there is a steady 255Vdc across the red 
and black wires.  At the instant of connecting my test prods to these 
wires the reading rushes to between 280-300Vdc before settling at 255Vdc.

This is the state where the tank stat is calling for heat but the boiler 
is off.  If I re-measure with the plug connected to the gas valve I 
measure only noise.


Turing the boiler stat to maximum (Red LED off, Green LED changing from 
on to rapid flashing, followed by ignition attempt) there is the 
briefest flicker on the voltmeter followed by the fault state.

HTH

Richard



-- 
Real email address is RJSavage at BIGFOOT dot COM

In message , rjs  
writes

>raden wrote:
>> In message , rjs 
>>
>
>>>
>> Well, you can ignore the volt and a bit - it's prolly just pickup and 
>>it's not really going to have much of an effect on a solenoid which 
>>requires 200v+ to work
>
>Agreed
>
>>  250vDC - I would have expected more, but it's a fairly pointless 
>>measurement if it's not connected to a load
>
>Also agreed.  I will re-measure it off load tonight.


With a load !


> But should this voltage be present all the time, i.e even when the 
>boiler is not providing heat?


No it shouldn't If it's there, then assuming the gas valve is working, 
then it's operating the gas valve


>
>>  4k sounds a reasonable figure - I don't actually know offhand 
>>without  looking
>
>Ditto
>
>>  By "no external call for heat, are you saying that you don't have 
>>mains  on the SWL ?
>
>Mains on, timer/controller set to continuous HW and CH but HW tank stat 
>set to minimum and temperature control on boiler also set to minimum 
>(or rather off).  This is my understanding of one of the steps in the 
>fault finding flow chart.   Next step is to increase the tank stat and 
>observe the red and green LEDs followed by setting the boiler stat to 
>maximum.  At that point the fan starts followed by sparking followed by 
>no(!) gas.


But if you have the volts to the gas valve and a sensible resistance on 
the solenoid, the you must get gas unless the gas valve itself is faulty


>
>What is 'SWL' an abbreviation of?


Switched live


>
>>  What's the resistance of the temperature sensor ?
>
>Will check tonight.   As it happens, both temp sensor and overheat 
>sensor were replaced along with the new heat exchanger a week ago.  I 
>had wondered about refitting the originals - maybe I should.
>

I had a case several  months ago where the problem was tracked down to a 
faulty new temp sensor


-- 
geoff

In message , Davide 
 writes

>
>raden Wrote:
>> [/i][/color]
>>
>> The Suprima gas valve is DC, so measuring on an AC range will give you
>>> a
>> completely false reading.
>>
>
>I stand corrected. Thanks for the info. My point was to check
>continuity on the solenoid as well as tension on the PCB output, that's
>all (which the OP has done).
>
>Please note, measuring a DC voltage on an AC range will NOT give you a
>completely false reading on a 500/2000V range;


Yes it will because it's smoothed


>the only difference is a
>rectifier voltage drop (0.5/1V at most), which is completely irrelevant
>for the purpose at hand.



>
>OTOH, measuring AC on a DC range I would not really recommend with an
>analogue meter, and is useless with a digital...


>--
>Davide


-- 
geoff

In message , Davide 
 writes

>
>raden Wrote:
>>
>>
>> raden Wrote:
>> The Suprima gas valve is DC, so measuring on an AC range will give
>> you
>> a completely false reading.
>>
>> Please note, measuring a DC voltage on an AC range will NOT give you a
>> completely false reading on a 500/2000V range;the only difference is a
>> rectifier voltage drop (0.5/1V at most), which is completely
>> irrelevant
>> for the purpose at hand.[/i]
>>
>> Yes it will because it's smoothed
>>
>>
>No it won't. Try simply using an AC range on a 9V or 12V battery, and
>then remeasuring said battery tension with a DC range. You'll get the
>same result (plus or minus the tension drop on the rectifier).


I'm sorry, but that is a total load of bollocks. Put a DVM on AC and put 
it across a battery and you'll get zero.


>You
>can't smooth DC - it's already smooth.
>

You're either incredibly ignorant about electricity or you're trying to 
wind me up.

I was going to slag you off, but to be honest, I just can't be bothered, 
but I will say that your basic electrical knowledge is fairly close to 
zero

-- 
geoff