Heads up on Immersion heater fault?

[DaveS79]

Hi all. Green self employed spark back again. Have had a request to look at immersion water heater problem. Have limited experience where these are concerned. He reports day time heating is working fine but night time not heating. What are first steps to diagnose. From little I know, know it can sometimes be the element itself and this needs to be tested. Cheers

 

[Evans Electric]

I would guess that the element is OK  if it works in the daytime  but not at night .   

So you need to look at the time switch , I'm also guessing its on Economy 7  ( May not be)     Time switch not set for a night time boost .  

 

[ProDave]

Is it one element or two?

Usually with most off peak cylinders there are two immersion heaters, the bottom one comes on at night on the off peak rate and the half way up one can be switched on at any time for a boost, sometimes with a timer.

But you can also do that with a Horstman timer with just one element.

Start by dead testing the element and the thermostat with an ohm meter.  Usually about 19 ohms for a good heating element.

Most common fault is the over heat cut out has popped out on the thermostat. You can try resetting it, but if it pops again change the thermostat.

 

[DaveS79]

I would guess that the element is OK  if it works in the daytime  but not at night .   

So you need to look at the time switch , I'm also guessing its on Economy 7  ( May not be)     Time switch not set for a night time boost .  

Thanks Evans. I will check if not two seperate immersions and have a look at time switch. Are these usually easy to set/program? have never had one personally or had opportunity to work with them.

 

[DaveS79]

Is it one element or two?

Usually with most off peak cylinders there are two immersion heaters, the bottom one comes on at night on the off peak rate and the half way up one can be switched on at any time for a boost, sometimes with a timer.

But you can also do that with a Horstman timer with just one element.

Start by dead testing the element and the thermostat with an ohm meter.  Usually about 19 ohms for a good heating element.

Most common fault is the over heat cut out has popped out on the thermostat. You can try resetting it, but if it pops again change the thermostat.

Thanks Dave. So possibly 2 elements in the one immersion tank? If the case is it easy for me to take out the element at bottom and test this? I think John Ward has decent video which might be of help

 

[Murdoch]

Thanks Dave. So possibly 2 elements in the one immersion tank? If the case is it easy for me to take out the element at bottom and test this? I think John Ward has decent video which might be of help

You don’t need to take the element out to test it ..... and if you do, you’ll probably have to drain the system ..

 

[DaveS79]

You don’t need to take the element out to test it ..... and if you do, you’ll probably have to drain the system ..

Cheers Murdoch. Just re checked the John Ward video he's pretty clear on testing procedure for the. Touch wood all goes well......

 

[Evans Electric]

You don’t need to take the element out to test it ..... and if you do, you’ll probably have to drain the system ..

I'd say you'd HAVE to drain wouldn't you   Murdo .     Mr Dave  don't start unscrewing  ant heaters  before draining .      Like Prodave said , check foe a faulty stat ,  check for the anti scald button hasn't popped up ,   check the element , as Dave said around 19ohms  ,   megger it to earth ,  and don't forget  Immersions can continue to work without blowing fuses when even theres just two prongs left in the water ,  it doesn't get hot but appears to work ,   best trick for that is put the clamp meter on ,  looking for around 12 A  .  

Removing immersions can be  a nightmare  if they won't unscrew  .    

 

[Sharpend]

Do not unscrew immersion, test as others have said first, removing immersion is like pulling the plug on a bath of water. 
now if the immersion looks to have been in from origin then let wet head do it, they can twist the tank if seized then it gets very expensive. You may if you are brave brush around the nut/thread to loosen any corrosion limescale etc then spray comprehensively with WD40 or the likes thereof leave to soak for at least two cups of tea if not three, then gently try with correct immersion spanner, as a tip, always apply pressure in direction to do up first, not too much just enough to see if it will move, this then breaks any scale seal on threads without risk of leaking. If it does move then you have to decide if you are going to undo it, if it doesn’t move then it’s a gamble or walk. 

 

[DaveS79]

I'd say you'd HAVE to drain wouldn't you   Murdo .     Mr Dave  don't start unscrewing  ant heaters  before draining .      Like Prodave said , check foe a faulty stat ,  check for the anti scald button hasn't popped up ,   check the element , as Dave said around 19ohms  ,   megger it to earth ,  and don't forget  Immersions can continue to work without blowing fuses when even theres just two prongs left in the water ,  it doesn't get hot but appears to work ,   best trick for that is put the clamp meter on ,  looking for around 12 A  .  

Removing immersions can be  a nightmare  if they won't unscrew  .    

Thanks again Evans

 

[Murdoch]

Removing immersions can be  a nightmare  

And should be left to plumbers ....

 

[DaveS79]

Do not unscrew immersion, test as others have said first, removing immersion is like pulling the plug on a bath of water. 
now if the immersion looks to have been in from origin then let wet head do it, they can twist the tank if seized then it gets very expensive. You may if you are brave brush around the nut/thread to loosen any corrosion limescale etc then spray comprehensively with WD40 or the likes thereof leave to soak for at least two cups of tea if not three, then gently try with correct immersion spanner, as a tip, always apply pressure in direction to do up first, not too much just enough to see if it will move, this then breaks any scale seal on threads without risk of leaking. If it does move then you have to decide if you are going to undo it, if it doesn’t move then it’s a gamble or walk. 

Cheers Sharpend could well of saved me a big insurance claim

 

[Evans Electric]

The worst one I was sent to was in the dreaded Varna Road   , Brum    Red light area   ( Google it )   Now demolished  with all the others .   Element open circuit ,   a very large West Indian gentleman standing over me &  quaking apprentice  .      After a search there was no way of shutting off the water ,  a valve up the street but we were threatened with death or worse  if we shut everyone off .   

So I say to the  Large guy  we could go for removing the heater ,  water will spill ,  but insert new one quickly .  "Do it Mon  , do it "   

So I instruct the apprentice  ...when I withdraw the old heater  you are standing there with new one which you lower into tank and screw up .  

 Heater out , I step away  ,  apprentice  steps in , inserts heater and gets the thread crossed  , water is  still coming , cannot get heater out ...water still coming .. heater out  ..  I try but thread is buggered ...."Water ham coming Mon . what the flup you do "!!!     

Don't panic  , don't panic ...we are now flooding a house house of ill repute  ,watched over by  large West Indian Guy  the size of a Transit van .

Keep calm & carry on  ......  find small  file  and clean up threads ,   Apprentice blocks up hole with his hand and a towel ......  then re- track round the thread in the boss  ..water comes ...."You know what you doing  Mon ?"   ....in goes  heater , on with spanner , no leaks  , reconnect flex  . 

Big black guy stuffs a load of pound notes in my hand  , about 6 times the what the bill would have been  ...then the scary bit   ...he grabs apprentice  who is now wide eyed with fear  , drags him  down the  landing  , points in a room .      " Ya know what I do in dere every night boy ?"      Apprentice shakes head  ...."Hi pray to Lord Jezus hevery night  for ma very soul  Mon "     And breaks out laughing  .  

We fled .    

 

[Sharpend]

Coward! You should’ve just walked away like a man with no fear! Not running to get rid of the dodgy bank notes he’d given you msl:

 

[Evans Electric]

He was a scary guy mate , apprentice was shaking .   Being morning  the place was empty ,  I think trade picked up in the afternoons  when there seemed to be a self inflicted  speed limit of  4 MPH  .  

 

[Sharpend]

He was a scary guy mate , apprentice was shaking .   Being morning  the place was empty ,  I think trade picked up in the afternoons  when there seemed to be a self inflicted  speed limit of  4 MPH  .  

why would everyone slow down to watch a big guy pray? That is respectful. 

 

[Evans Electric]

Naw  I think there was more to it than that mate . 

 

[kerching]

We're all the notes stuck together and that's why you got too much?

 

[Evans Electric]

We're all the notes stuck together and that's why you got too much?

UUgh  !!!   Gross    (As we say in the States )   (( Or was it "Awesome")) 

 

[DaveS79]

The worst one I was sent to was in the dreaded Varna Road   , Brum    Red light area   ( Google it )   Now demolished  with all the others .   Element open circuit ,   a very large West Indian gentleman standing over me &  quaking apprentice  .      After a search there was no way of shutting off the water ,  a valve up the street but we were threatened with death or worse  if we shut everyone off .   

So I say to the  Large guy  we could go for removing the heater ,  water will spill ,  but insert new one quickly .  "Do it Mon  , do it "   

So I instruct the apprentice  ...when I withdraw the old heater  you are standing there with new one which you lower into tank and screw up .  

 Heater out , I step away  ,  apprentice  steps in , inserts heater and gets the thread crossed  , water is  still coming , cannot get heater out ...water still coming .. heater out  ..  I try but thread is buggered ...."Water ham coming Mon . what the flup you do "!!!     

Don't panic  , don't panic ...we are now flooding a house house of ill repute  ,watched over by  large West Indian Guy  the size of a Transit van .

Keep calm & carry on  ......  find small  file  and clean up threads ,   Apprentice blocks up hole with his hand and a towel ......  then re- track round the thread in the boss  ..water comes ...."You know what you doing  Mon ?"   ....in goes  heater , on with spanner , no leaks  , reconnect flex  . 

Big black guy stuffs a load of pound notes in my hand  , about 6 times the what the bill would have been  ...then the scary bit   ...he grabs apprentice  who is now wide eyed with fear  , drags him  down the  landing  , points in a room .      " Ya know what I do in dere every night boy ?"      Apprentice shakes head  ...."Hi pray to Lord Jezus hevery night  for ma very soul  Mon "     And breaks out laughing  .  

We fled .    

Hahaha quality. East London got a few characters like that somehow managed to avoid them so far