Socket outlet Or Fused Spur

[EFLImpudence]

Because as it is, I think it should be rcd protected? not sure.

Doing what you asked would make no difference in that regard.
If you meant an RCD FCU then, no that is not the way to do it. One of them behind a WM could be most inconvenient.

If you can change the MCB for an RCBO (if available for your Consumer Unit), or move the circuit to an RCCB if there is one, then you can do that if you want to.
If they are not available then it is likely it was installed before required so I wouldn't bother, but up to you.

 

[EFLImpudence]

Ah, I am sorry - just realised why you asked as you did - because of what RF said.

As I said, if it was installed before RCDs were required - or if someone else did it before it was yours - then it was likely compliant when installed as far as you can tell so I wouldn't bother.

 

[The Baker]

So you're suggesting that the current flows from the electrode, through the ionised gas, through the burner metalwork to the gas supply pipe, back to the gas meter, down the earth wire from the gas meter to the main earthing terminal at the consumer unit, then down the boiler circuit's CPC back to the boiler.

This doesn't seem likely to me. I think it's more likely that the burner metalwork is connected within the boiler to its electrical earth. In fact I'd say that would be a requirement, as no boiler is likely to be double-insulated.

Have you tried operating one of these boilers with the supply earth connection disconnected?

Of course there is value in checking for earth continuity to the socket or FCU, e.g. as part of an EICR.

Sorry about images being on their side


I got called out to a new install.

Over the phone the installer said this Intergas Combi Boiler would work OK in When running hot tap but would keep locking out on Central heating.

The boiler was temperately using extension to supply electricity to the boiler.

I plugged my Tester into the socket of this extension which indicated an earth fault.

On examination this extension lead had only two conductors.

I replaced it with a new extension and the boiler ran OK.

When running the Manufactures Software with my lap top connected to the boiler the display was showing 5.9 at 1300rpm fan speed and 8.32 at 3200 rpm once I had connected the new extension cable.

The later Boiler PCBs have been upgraded to allow the operators to check ionization current by pressing a button on the display but not on earlier models.

I can only assume the boiler obtained enough ionization current through the copper pipework to generate enough ionization current when running at maximum fan speed, but I dont fully understand why,

Images of display read out in next couple of posts.

 

[The Baker]

 

[The Baker]

 

[flameport]

Gas boilers require an earth connection, and with some boilers in some circumstances no earth will cause problems.

For those installing or working on a boiler, the test is whether the earth is connected to the boiler or not. That is easily achieved by testing for continuity between the metal casing of the boiler and the earth pin of the plug, or between the boiler casing and the metal screws that fix the FCU to the backbox.
A standard multimeter can be used for that, and for a new installation that should be checked before switching the boiler on.
Most 2 pole voltage indicators also have a continuity function.

If there are problems with the earth for the electrical installation as a whole and using a plug in tester at a nearby socket outlet revealed that possibility, then that would need to be investigated and repaired by an electrician.
The actual loop impedance value is entirely irrelevant to the boiler operation, and in normal circumstances can be anything from almost zero ohms to several hundred ohms. Whether that value is valid or not is entirely outside of the scope of boiler installation and repair.

 

[Harry Bloomfield]

Gas boilers require an earth connection, and with some boilers in some circumstances no earth will cause problems.

I agree with all of that in your post, especially the need to protect yourself to enure the system has some sort of earth, other than the last part of the above sentence. Why might a boiler have operational issues, if it lacked an earth?

 

[flameport]

No earth at all = flame rectification won't work.

With some boilers, and depending on how it's connected, as there may be other paths to earth via the pipework, assuming it's all metal, which in many cases it isn't.

 

[Harry Bloomfield]

No earth at all = flame rectification won't work.

With some boilers, and depending on how it's connected, as there may be other paths to earth via the pipework, assuming it's all metal, which in many cases it isn't.

You would like my place - The DP switch provides an earth, the flow and return have a separate earth and every radiator has an earth at the back of them. My entire system uses copper throughout.

 

[endecotp]

No earth at all = flame rectification won't work.

Is it not the case that what’s needed is a connection from the gas burner metalwork to the flame detection circuit’s earth, which would be a connection within the boiler?

 

[Harry Bloomfield]

Is it not the case that what’s needed is a connection from the gas burner metalwork to the flame detection circuit’s earth, which would be a connection within the boiler?

That is the way I would expect it to work, making an actual earth irrelevant!