New boiler tripping RCD

[TheGovernor]

Just reporting in, no tripping since the pump etc, but I'm still waiting and seeing.

I do have another problem Since the cylinder went in (it's a Gledhill vented Stainless one) when the water is heating we get an almighty rumbling/vibration sound that I'm 99% certain comes form the boiler. It doesn't happen at all when heating the rads... seems to me that the flow from the pump is making the cylinder vibrate as it's okay when doing the rads and also quiet when doing both HW and CH... only does it on water only...

Anyone know what the solution to that might be?

It's not easy to catch using a phone but here's a couple of examples:

 

[Agile]

I used to have a clamp on ammeter with a 30 mA range which was very useful for checking for earth leakage currents.

Your problem reminds me of something a little similar with intermittent RCD tripping. Several engineers had come out from his local boiler service agents and been unable to find the fault.

I arrived and had a very quick look and made a small change.

He made me a cup of coffee and we chatted generally while I ran the boiler on heating. I was totally relaxed and he seemed to be getting a little uncomfortable. I carried on calmly chatting!

After a little longer he could not keep quiet any longer! He said the boiler had run longer than before and asked me why! I replied that I had disconnected the boiler's 230v thermostat connection.

I deduced that the long run under the floor from boiler to room thermostat was probably touching on the damp under floor concrete and causing an earth leakage. I asked him to get a wireless thermostat fitted.

Later he confirmed a builder had extended the thermostat wire under the floor and just twisted wires together with a bit of tape round them! Not the way to do that properly.

The other local service agent had sent people out three times and the owner was a bit surprised that I had guessed at the likely cause within 10 minutes and bypassed the fault.