Boiler keeps tripping the RCD

[Kalifornia777]

Hi guys need a bit of advice.

I’ve got a vallant boiler circa 8 years old. Something is tripping the boiler, I’ve narrowed it down to the fused spur from where the boiler is connected. As soon as I turn the fuse on it trips the RCD. This happened about a month ago and after a couple of days it went away. The problem is now back. I have homeserve cover but they can’t see me till Thursday.

 

[JohnD]

RCD trips are more often than not water related.

Your boiler contains water. So does its electric pump and its electric motorised valves. Look for any signs of a leak dripping onto an electrical part. Verify that the condensate drain is running freely, not backing up because blocked e.g. with dirt or frozen.

 

[CBW]

Quite a usual suspect on those is the pump causes it to trip because the housing is full of water.

 

[Kalifornia777]

Thanks for the pointers. I found a very small drip on the bottom right of the boiler

I’ve got a vallant ecotec plus. Roughly what would be the cost to replace the pump Time and materials

 

[Kalifornia777]

When the boiler trips, why does it knock out the entire downstairs electric. Is there a way to contain it just to the boiler. I don’t want to go away for the week and the boiler has a hissy fit and my Cctv, fridge, freezer all stop working

 

[JohnD]

this will happen if the boiler has been installed on the same circuit as the other outlets you mention.

Your RCD presumably control a number of circuits, when it trips, all of them will go off. This is quite normal although it is possible, and more expensive, to provide a dedicated RCBO circuit.

It might be possible to wire your boiler to a different circuit, for example using a plug and socket to the cooker outlet, but if that is not RCD protected, you will be creating a danger of shock or electrocution.

All the time your boiler is dripping internally, it may be damaging a circuit board inside, which will be an expensive repair. You would do better to turn it off at the wall switch until the fault is fixed. It is unlikely that the leak will repair itself.

Buy a couple of panel heaters or oil filled radiators to tide you over.

 

[CBW]

When the boiler trips, why does it knock out the entire downstairs electric. Is there a way to contain it just to the boiler. I don’t want to go away for the week and the boiler has a hissy fit and my Cctv, fridge, freezer all stop working

Turn off the fused spur to it. Regards to cost depends on engineer and what is charged in a London.

 

[Kalifornia777]

Thanks for the info... I’ve turned off the fused spur....

I have one of these big tanks do you know if if it has an immersion facility so I can at least get some hot water.

 

[CBW]

It should have yes, look for trailing white flexible cable from it to a spur, there might be two of them and turn them on.

 

[JohnD]

they usually do, but I don't know if yours is connected. I'd expect to see a thick, rubbery-feeling flex emerging from one or both of those square covers, and going to a switch on the wall nearby. I'd also expect, in your Consumer Unit, to see one (or two) B16 breakers, labelled "immersion heater"

As you've realised, it is very useful to have electric immersion heaters in a hot water cylinder. Although they are much more expensive to run, they save a lot of inconvenience as you can turn them on when the boiler fails.

edit
yes, the label you've photographed says the cylinder includes immersion heater(s)

 

[Kalifornia777]

I found the cable it’s plug into the wall. However the other cable goes into a big box of cables which seem to link up to a horseman. Switching the plug on doesn’t seem to do anything. The horseman doesn’t come on as it seems to be powered by the same fused spur connected to the boiler.

there’s no mention of Immersion on the CU

 

[John D v2.0]

Switching the plug on doesn’t seem to do anything.

When you say doesn't seem to do anything, do you mean the water in the tank is cold, then after leaving it on for a few hours, it's still cold? If not, try doing that.

 

[CBW]

What does the switch with the red neon do?

 

[Kalifornia777]

Just checked the the pipes. These two are hot but still no hot water. See pictures for more info

 

[Kalifornia777]

What does the switch with the red neon do?

I think it’s connected to the boiler but can’t be sure as some of the wiring is behind the wall, all I know is when it’s on the RCD trips