Noisy Servowarm Elite

[Agricola]

I have a Servowarm Elite 50 gas boiler to a pumped hot water and C/H system. About 3 weeks ago the pump became noisy and sounded as if it was running 'dry'. I discovered that a previous 'plumber' had turned off the supply to the header tank and not reopened it. The supply was turned on and all seemed fine. 2 days ago the boiler started to make a different noise and would only stay lit for about 10 secs. I have changed the pump in case that was the problem and bled the system as far as I am able. ( there does not appear to be any bleeds except on the radiators). The boiler now stays lit and water is being pumped round the system. The only problem is that the noise is still there. It is coming from an item on the PCB. A small blue 'cube'. It sounds as if it is clicking rapidly and loudly.
Can anyone help as to problem and solution.

 

[meldrew's_mate]

I think the Servowarm Elite is Glowworm based, with the pump built-in. If you use a piece of INSULATED plastic hose or tubing you can listen for the noise with more precision and home in on the noisy part of the PCB.

Are you sure it's not the pump bearings running dry?

Is the ignition sparking continuously?

 

[Agricola]

Thanks for the prompt response.
The pump is within the casing of the boiler. I'm positive that the pump is Ok and its not the bearings ( Put a new pump in yesterday). The noise definately comes from the PCB and its the largest item on the PCB which is this blue cube. This could be a relay or something which is 'chattering'. I will check on the ignition but I don't think its that.

Rgds

 

[meldrew's_mate]

Power down & remove the PCB.

Carefully inspect the soldered joints around this blue relay
Look for signs of arcing (black ring around the pin where it pokes through), and cracked joints. Resolder as necessary, though it will be obvious if it has arced. If you do nothing arcing will kill it in a few days!!

 

[chrishutt]

its the largest item on the PCB which is this blue cube

Could it possibly be a transformer? That might make a noise like you describe.

 

[Agricola]

The good news is that the noise has stopped all on its own. The boiler is working fine and water is being pumped round the system. The only thing I have a doubt over is whether the pump is now running all the time. Havn't been around enough to determine at the moment. If the blue cube was a pump relay and finally failed in the 'on' position then it could explain a constantly running pump if that is what I have.
Any body know where you can get spares for the PCB or a new PCB for the Servowarm Elite?

 

[kevk]

My system seems to be running all the time even tho the rads are cold and no pilot light,rads do seem luke warm....do any of you guys-gals know whats causing it to run?
Cheers
Kev