Rangemaster RDW459FI/SF tripping RCD. Heater element gone?

[RANGEmasterG]

Model : RDW459FI/SF
(I think really its a Hotpoint unit as I have letter from Hotpoint sent to a previous owner re: fire risk, stating it might be a Hotpoint FDW20 / FDW60 / FDW65A, its a built in unit)

On Monday evening my downstairs sockets tripped the RCD whilst the dishwasher was running. I reset the RCD and everything came back up ok, including the dishwasher.

On Tuesday evening the RCD tripped again, part way through the dishwashers cycle. I reset the RCD, but each time I attempted this the dishwasher would briefly resume before immediately tripping the RCD back off.

What I did next:

• Unplugged the dishwasher and reset the RCD. Everything else came back up ok.
• Filled a kettle and plugged that into the dishwasher socket. Kettle started boiling ok. So suspect socket is ok.
• Dismantled dishwasher plug to check the fuse. Fuse has continuity.
• Plugged the dishwasher back in and ran a cold water cycle. Cycle completed ok. Suspect plug is ok, but suspect water heater element has gone. This ties up with the state the dishwasher was in when it first tripped. The cold pre-rinse had completed, and the tablet had been dispensed.

So at this point I am expecting that the water heater has gone. Got the dishwasher pulled out, water and power disconnected. Opened up the bottom of it and removed the heater element. I did see some water on one of the heater terminals, but I put this down to droplets running down from when I was disconnecting one of the water pipes into the heater. I measure 28 Ohms across the heater terminals. Which makes me think it might actually be ok? I was expecting to see no continuity. One of the terminals to the wire which runs across the heater has some green corrosion to it and a rusty mark/stain on the plastic connector body.

I have tried searching specifically for a heater for the Rangemaster model number, with varying success and prices ranging from £13 to £53! It seems like a very common design that goes in pretty much every dishwasher with a 1800W flow through heater.

So, I have some questions:

1. Is the heater element the likely cause of the RCD tripping?
2. Is the fault internal to the heat element? Or is it to do with a fault in how its connected into the machine?
3. Is the 28 Ohm reading “normal” for a 1800W flow through heater?
4. If I can’t get hold of a “Rangemaster RDW459FI/SF” specific heater is it ok to use a generic one from e-spares say? Like this : https://www.espares.co.uk/product/es1250400

Appreciate any help anyone can offer.

Thanks,
George

[electrofix]

fast way
run dishwasher till it trip

remove plug from socket, disconnect heater, plug back in and reset trip

it should continue where it left off and if no trip you found it

not made by hotpoint. all indications are its a cheap import
I would contact the site shop as the heater seems steep at £42 and since Espares hide the numbers to stop you getting a better deal

generic heaters are normally ok

Dave

[RANGEmasterG]

Thanks for the response Dave, would doing that give a different result to the cold water cycle I ran?

[electrofix]

did it trip on the cold cycle

Dave

[RANGEmasterG]

No it completed the cold cycle fine, drained as normal etc.

[electrofix]

then its very likely the heater then

Dave

[Author]

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