Potterton Suprima 70 slow amber flashing light???

[Luke74]

Hi,
I have a Potterton Suprima 70 boiler.

The issue is that the light on the boiler flashes amber (Slowly) and only ignites when hot water is requested either by timer or manually provided the hot water is not up to temperture.

However, the central heating does not come on at all with by the theromstat or manual bypass. The only way I can heat the house is when the boiler is heating water as above and then I,m able to turn the heating control on.

My boiler had a replacement PCB sometime ago (By previousowners) and I have changed the Honeywell 3 port actuvator.....one question through is that valve head does rotate, but not by much i.e. 20 degress and therefore the actuvator does not fully close/open by the spring as per normal?

So my question is how far should my 3 port valve rotate and if this is not the problem, please can someone kindly give me an idea as to what the problem could be re: no heating .....by the way the room thermostat is fully on and made no difference and my water pump works fine.

Thanks for your help here, I'd be very grateful.

 

[MANDATE]

It sounds to me that your problem could be related to the 3port valve.
The actuator head contains two micro switches each with two sets of contacts.
One set of contacts switches power to the motor so it drives the valve half way along its range.
At the mid position those contacts open and another set switches power to the motor to drive the valve beyond the mid position when CH only has been selected.
If any of the contacts are dirty/burnt it prevents the power operating the motor.
So this could prevent the valve going to the CH position.
Now besides the above there are contacts in the second micro switch and when this switch is triggered during the second half of the range the contacts switch power across from a live wire to the orange wire which leaves the valve to feed the boiler and pump.
So it looks like either the valve/motor is not moving over the last half and not triggering the 2nd micro switch or the 2nd micro switch is faulty.
In either case, sounds like replacement head is needed

 

[Luke74]

Hi,

Thanks, I have checked the 3 port valve and last night the system seemed to be working perfectly i.e. selected hot water and/or central heating and the boiler did it's thing.

Today however, same problem has reoccurred.

The boiler flashes amber if you select to heat water or CH, but nothing happens.

I can't see how the fault can be the 3 port valve and the heating also came on when I turned up the room stat. Water pump also seems to work fine.

The only thing I can think is that the pipes to a few of the radiators may be sludged up (Because two of my radiators do not heat up whilst the rest do...when the boiler decides to work), although this would not explain why the boiler doesn't work when I just want to heat the water.

Please can someone advise what other problems could cause this i.e. thermister, boiler stat, PCB??? and if you were me in what order would you check each component, i don't have a multimeter.

Thanks in advance, I'd be really grateful for your help.