buzzing noise from boiler

[robraw]

I have a ferroli optima 700 and there's a sort loud buzzing noise coming from the area of the modulating regulator gas valve or operator gas valve. It started shortly after switching the electric power off from the boiler and then trying to run the hot water and I forgot to switch the power back on. I get hot water and heat but it's just the noise. Any ideas as to the problem?

 

[robraw]

It seems I have hot water but no heat to the radiators now.

 

[LUNAT]

HI

noise can come from many places.very difficult without more details.

 

[robraw]

I have noticed that I can get hot water to the radiators to a point and then the noise starts and the flames go out only leaving the pilot light on. Could this be a temperature sensor? as I had replaced one last year due to low heat to the radiators. The buzzing noise seems to be coming from the modureg area, there is a small green part on the front of the modureg where is seems to be the loudest. But the noise really starts once the water temperature rises when Ii switch on the C.H.

 

[LUNAT]

HI

it sounds like system is scaled up.was the system ever flushed ? if not try some descaling chemical .

 

[robraw]

No, it has never been descaled. Is it a straightforward job? Where do you put the chemical in?

 

[LUNAT]

HI

release water from the system .choose highest point radiator.add chemical in to the system .leave it running normal for few days or weeks if the system is bad. then flush when water is hot.fill water, run, flush with plain water .repeat this few times to make sure all the dirty water has come out.
finally after about two weeks add inhibitor which will keep the system healthy.if not sure about this check the forum.

 

[Agile]

The smoothing circuit on the PCB may be failing.

Do you have a battery operated scope you could use to measure the 100 hertz ripple level on the DC supply?

Tony