OSO Direct 20 RD Water Heater Problem

[ta6imc]

Evening all.

I have the above water heater in my apartment wired to come on during Economy 7 hours with the option of a seperate booster heater if needed.

Recently when the Economy 7 heater kicks in it's tripping out the RCD on the main board and blowing the 13amp fuse pior to the Horstmann switching unit.

I'm fairly confident I've narrowed the problem down to the lower heater.

Is the heater element within the unit replaceable or will the whole water heater need replacing? (hope not) The water heater itself is only 3 years old so I wasn't expecting to have trouble so soon.

Any advice appreciated.

Ian

 

[Joe4542]

Hi,
I would agree that the lower element (economy 7 one) is the likely culprit, but to be sure it would be wise for you to confirm a problem with it, prior to proceeding.
This would involve turning off the power, removing wires from the immersion element and then measuring the resistance accross the element terminals,with a multimeter - if faulty you are likely to see one of two problems (or both...)
1.The element has gone 'short circuit' and has a very low resistance , say lower than 10 ohms.
2. There is a leakage path to earth - any continuity (connection) from either element terminal to the earth connector could cause RCD tripping.

If the element IS faulty it can be replaced, but would involve draining down the cylinder, and could well be v.difficult to remove - I've never actually worked on these models, so unsure if any special tools are required to do so.

Hope this helps.

 

[seco services]

sounds like the immersion element has blown.
just change the element.

 

[ta6imc]

Thanks for the speedy replies guys.

Joe I've just checked the resistance between the 2 terminals and it's 55 ohms, both terminals to earth is in the meg ohm range.

Seco services, I'm happy dabbling with electrics but how much work is involved with changing the element, is it best left to a plumber?

Thanks

 

[npaisnel]

Sorry, should have started a new thread, I somehow replied to thread instead. so my text deleted.

Neil