Hi,

I have a Potterton Suprima 80 which in the past has had all the usual
lockout problems. I bought a replacement PCB from CET Ltd a couple of
years ago and have had no problems since, until now. However, what I'm
now seeing is different from the lockout problem I had previously.

The most common symptom now is that the thermostat will call for heat,
the LED will flash green and the boiler will light as normal. However,
after only a few seconds it will switch off again and the LED will
revert to solid red. If I keep cycling the thermostat down then up to
cause it try again it will eventually stay lit for a while (normally).
Sometimes though, no matter what I do with the thermostat or power
cycling the boiler etc it won't even try to light - the LED will remain
resolutely solid red.

So, do you think that the PCB is playing up again, or are there other
things I should investigate before ordering a new one? I don't know if
it's relevant or just sod's law, but it is worse when the outside
temperature is particularly cold (contraction of dodgy solder joints?).

Thanks,

Craig

On Mon, 03 Dec 2007 11:31:43 +0000, craig wrote:

The most common symptom now is that the thermostat will call for heat,
the LED will flash green and the boiler will light as normal. However,
after only a few seconds it will switch off again and the LED will
revert to solid red. If I keep cycling the thermostat down then up to
cause it try again it will eventually stay lit for a while (normally).
Sometimes though, no matter what I do with the thermostat or power
cycling the boiler etc it won't even try to light - the LED will remain
resolutely solid red.

Green OFF and red ON indicates that the boiler isn't getting a
call-for-heat from the controls. You need to check whether there really is
a call signal - if there is one up to the boiler then either there's a
wiring fault between the boiler's terminals and the PCB or there's a fault
on the PCB (what do you expect with these cheap refurbs from that dodgy
fella? ;-))

OTOH if it's going to green flashing 2Hz and solid red it's probably a
circulation issue - pump or blockage.

--
John Stumbles

I've got nothing against racists - I just wouldn't want my daughter to marry one

John Stumbles wrote:
Green OFF and red ON indicates that the boiler isn't getting a
call-for-heat from the controls. You need to check whether there really is
a call signal - if there is one up to the boiler then either there's a
wiring fault between the boiler's terminals and the PCB or there's a fault
on the PCB (what do you expect with these cheap refurbs from that dodgy
fella? ;-))

OTOH if it's going to green flashing 2Hz and solid red it's probably a
circulation issue - pump or blockage.


Thanks for that John - it's definitely solid red, which implies that
it's not seeing the call for heat as you say. Do you know where I can
get a schematic for this PCB, so that I know where to put a meter to see
if it's getting that far? All I have at the moment is the 'Installation
and Service Instructions'.

In message , craig writes
Hi,

I have a Potterton Suprima 80 which in the past has had all the usual
lockout problems. I bought a replacement PCB from CET Ltd a couple of
years ago and have had no problems since, until now. However, what I'm
now seeing is different from the lockout problem I had previously.

The most common symptom now is that the thermostat will call for heat,
the LED will flash green and the boiler will light as normal. However,
after only a few seconds it will switch off again and the LED will
revert to solid red. If I keep cycling the thermostat down then up to
cause it try again it will eventually stay lit for a while (normally).
Sometimes though, no matter what I do with the thermostat or power
cycling the boiler etc it won't even try to light - the LED will remain
resolutely solid red.

So, do you think that the PCB is playing up again, or are there other
things I should investigate before ordering a new one? I don't know if
it's relevant or just sod's law, but it is worse when the outside
temperature is particularly cold (contraction of dodgy solder joints?).

Do you have a red or black HT lead ?

If it's red, then "the boiler will light as normal. However, after only
a few seconds it will switch off again" is a classic flame sense failure
problem.

Otherwise, you could have a blockage or pump failure which means that
the water isn't getting the heat out of the heat exchanger quickly
enough, and it's going into overheat

If neither of these, ring me, the number's on the CET website, and I'll
see if I can diagnose the problem


--
geoff

In message , John Stumbles
writes
On Mon, 03 Dec 2007 11:31:43 +0000, craig wrote:

The most common symptom now is that the thermostat will call for heat,
the LED will flash green and the boiler will light as normal. However,
after only a few seconds it will switch off again and the LED will
revert to solid red. If I keep cycling the thermostat down then up to
cause it try again it will eventually stay lit for a while (normally).
Sometimes though, no matter what I do with the thermostat or power
cycling the boiler etc it won't even try to light - the LED will remain
resolutely solid red.

Green OFF and red ON indicates that the boiler isn't getting a
call-for-heat from the controls. You need to check whether there really is
a call signal - if there is one up to the boiler then either there's a
wiring fault between the boiler's terminals and the PCB or there's a fault
on the PCB (what do you expect with these cheap refurbs from that dodgy
fella? ;-))

Ha !

OTOH if it's going to green flashing 2Hz and solid red it's probably a
circulation issue - pump or blockage.


--
geoff

In message , craig writes
John Stumbles wrote:
Green OFF and red ON indicates that the boiler isn't getting a
call-for-heat from the controls. You need to check whether there really is
a call signal - if there is one up to the boiler then either there's a
wiring fault between the boiler's terminals and the PCB or there's a fault
on the PCB (what do you expect with these cheap refurbs from that dodgy
fella? ;-))
OTOH if it's going to green flashing 2Hz and solid red it's probably

circulation issue - pump or blockage.


Thanks for that John - it's definitely solid red, which implies that
it's not seeing the call for heat as you say. Do you know where I can
get a schematic for this PCB, so that I know where to put a meter to
see if it's getting that far? All I have at the moment is the
'Installation and Service Instructions'.

You will never get a schematic for the pcb

All you can do is look at the interconnection diagram in the
installation manual (which is what I presume you mean you have) and
check that you have mains on the switched live when there is a call for
heat

You do seem to be indicating that there is more than one fault here



--
geoff

On Mon, 03 Dec 2007 22:58:36 +0000, geoff wrote:

Do you have a red or black HT lead ?

If it's red, then "the boiler will light as normal. However, after only
a few seconds it will switch off again" is a classic flame sense failure
problem.

Wouldn't it go either into 16Hz flashing green trying to relight, or
lockout?

Otherwise, you could have a blockage or pump failure which means that
the water isn't getting the heat out of the heat exchanger quickly
enough, and it's going into overheat

AIUI you'd have solid RED accompanied by 2Hz flashing green in that case
(boiler temp satisfied).

However I'm going by the codes I have for the Suprimas I've come across
but I know that there's a different design of PCB. Do you know if it
has different diagnostic codes? The codes I know are as below:

Suprima LED Indicators

NORMAL INDICATION

Green Red Status

OFF ON Mains ON Only
2Hz ON Ext. Call for Heat
(Boiler set to STNDBY Temp. Cont set to 'O' Off)

2Hz OFF Ext. Call for Heat
(STNDBY switch to ON Temp. Cont to Max.)

16Hz OFF Ignition
(i.e. Gas & Sparks ON)

ON OFF FLAME Detected

2Hz ON Boiler Temp Control Satisfied

FAULT INDICATION
ON 2Hz Blocking -
Mains Freq incorrect
or Air Switch Fault
1 min. or Reset
button held in to force
a restart

2Hz 2Hz Earth Fault or
Mains Reversal

OFF 2Hz Lockout


--
John Stumbles

Fundamentalist agnostic

In message , John Stumbles
writes
On Mon, 03 Dec 2007 22:58:36 +0000, geoff wrote:

Do you have a red or black HT lead ?

If it's red, then "the boiler will light as normal. However, after only
a few seconds it will switch off again" is a classic flame sense failure
problem.

Wouldn't it go either into 16Hz flashing green trying to relight, or
lockout?

Well, er yes

What it actually does is spark 13 times, then stops turns the fan off,
sequences again , and then a third time , then goes into lockout


Otherwise, you could have a blockage or pump failure which means that
the water isn't getting the heat out of the heat exchanger quickly
enough, and it's going into overheat

AIUI you'd have solid RED accompanied by 2Hz flashing green in that case
(boiler temp satisfied).

I must be getting rusty

It's several years since I actually worked on one myself

I spend most of my time answering the phone and doing paperwork now,
It's too dangerous for me to do bench work, as when I get called away to
the phone, I might have forgotten to do part of a test, therefore, with
certain exceptions, I don't go near a soldering iron anymore

--
geoff