my bottom immersion nay heating the water during the night

[rabbroon]

if anyone knows about immersion heaters ? got economy 7, but my bottom immersion nay heating the water during the night, its getting 240v when the off peak supply comes on but does not heat up! I took a resisitance reading getting 35 ohms off the live to neutral,! just to check I tested the top immersion where I got 17 ohms. Does this mean the bottom element has kicked the bucket?

 

[stuartcourt]

Re: qualifications and experience snobs

sounds like it and I take it you didnt work out the new post

 

[rabbroon]

Re: qualifications and experience snobs

got to post 6 messages before I cando that!! thanks

 

[Marvo]

Welcome to the forum Rabbroon.

I've made your heating question into a thread of it's own for you.

 

[oldtimer]

if anyone knows about immersion heaters ? got economy 7, but my bottom immersion nay heating the water during the night, its getting 240v when the off peak supply comes on but does not heat up! I took a resisitance reading getting 35 ohms off the live to neutral,! just to check I tested the top immersion where I got 17 ohms. Does this mean the bottom element has kicked the bucket?

Measure the resistance across the element and via the stat

 

[rabbroon]

Thanks Marvo

 

[rabbroon]

what are the readings I am looking for, ? whats good whats bad?

 

[Marvo]

If the element measures 35 ohms it's going to consume roughly 1.5 kilowatts. This might be correct, I'm not sure to be honest.


Really you need to check the current flowing though the element and compare this to the kilowatt rating written on the element. I'd also run an IR test but you'd need a mega tester to do this. If you're unsure about safe isolation or if you don't have the test equipment then call an electrician rather.

 

[oldtimer]

Test across the element and you should get 18-19 ohms then measure across live and neutral as it comes into the element cover ie before the stat and you should get the same if not your stat may have a problem.

Well done for referencing the top unit as this is exactly the same as the bottom one so if that is working ok then thats a good reference point

 

[rabbroon]

Right both are 3kv immersions! the top one the Boost supply has 17ohms reading on the live and neutral coming in the immersion and also 17ohms across the element itself however the bottm immersion has 35 ohms in the incoming supply and 35 ohms between the live and neutral through the element! So do we agree that there is something up with the off peak immersion and needs replacing?

 

[chopper76]

Not something stupid like the thermal cutout tripped?

 

[rabbroon]

don't understand that Chopper76 there is no reset on the thermostat.

 

[Marvo]

I'd remove the bottom element and visually check it, the 35 ohms reading isn't right for a 3 kW element. Also check for limescale build-up in the tank whilst the element is out.

 

[Sintra]

Not the thermal cut out if its giving 35 ohms across the element. 17 ohms is about right for a 3KW element so I would suggest the one at 35 ohms is replaced.

 

[oldtimer]

I'd remove the bottom element and visually check it, the 35 ohms reading isn't right for a 3 kW element. Also check for limescale build-up in the tank whilst the element is out.

Marvo he is in Scotland we don't do limescale up here the same as we don't do Part P!sh

 

[oldtimer]

Right both are 3kv immersions! the top one the Boost supply has 17ohms reading on the live and neutral coming in the immersion and also 17ohms across the element itself however the bottm immersion has 35 ohms in the incoming supply and 35 ohms between the live and neutral through the element! So do we agree that there is something up with the off peak immersion and needs replacing?

Just do what I said in my post ie test on the element and then through the stat you will not have a high limit on the stat

 

[Marvo]

Marvo he is in Scotland we don't do limescale up here the same as we don't do Part P!sh

Lol, I'm in Cape Town so my knowledge of Scottish water is limited, I read somewhere it's the same colour as beer

 

[tazz]

Not much difference between 17-35 ohms....if the element had gone would suggest a full o/c or a least a higher reading than 35 ohms. if the element had burnt out would suggest a short circuit to earth

 

[oldtimer]

Lol, I'm in Cape Town so my knowledge of Scottish water is limited, I read somewhere it's the same colour as beer

Could never understand why we threw money to the electronic plants because they threatened to go to England only problem was the they used a lot of RO water I know because I worked in one because it was easy to filter our soft water. Mind I still chuckle when I see descaler kits in the local diy shed