Intermitten cut out Central heating pump

[jackys]

Hi there

I am new to this so I hope you will bear with me. I have a Gloworm Micron 80FF gas boiler with a towerchron timer - I cannot see the name of the pump. The boiler is just over 4 years old. The pump is about 2 years old - the timer is over 10 years old.
Having recently turned the central heating on we have experienced loud kettling noises in the wall boiler itself - this is followed by a very loud noise in the presumably from the hotwater tank then a rushing of air/water? through the whole house.
We called in a central heating engineer who discovered that there was no power/connection from the circuit board to the pump but this appeared to be an intermittent fault. We therefore replaced the circuit board.
Prior to that the the main thermostat in the living room never really turned itself off fully and had a dim glow even when the stat was not calling for heat. The new board seems to have fixed that in that when it is off it is really off and when on there is a bright glow which we did not get before.
Thought this had solved the problem - it has not - the stat clicks on - the pump comes on the boiler ignites and the system operates as it should
However, intermittently the pump stops whilst the boiler is still on and then kicks in again (the central heating engineer managed to replicate the sound by stopping the pump)
The new circuit board has not fixed the problem - I have been unable to find any information on this forum or other searches with a similar problem - can anyone help please?

 

[gas4you]

New pcb is faulty? or perhaps pump is blowing part of the pcb?

 

[jackys]

thanks for that - which should i try first - pump or board? I understand the board is non returnable - I do still have the old one

 

[gas4you]

Does the boiler stat appear to work?

I a wondering if there is an ntc that is giving false readings to the pcb

 

[jackys]

Where do I find the boiler stat? sorry - what is an ntc? Do I need an engineer back to check these things?

 

[gas4you]

I think, with respect, that if you do not know where or what the boiler stat is you need to get an engineer back to check it over

 

[jackys]

sorry, that was stupid of me - -i was not sure whether there was an internal setting and that was what you were referring to - yes the heating control works .