Immersion heater not heating.
Discussion
The large Immersion tank was installed around 15 years ago, and it hasn't worked in the 4 years we've lived in this house. As we have 16 solar panels on our roof, it would make sense for us to heat some of our water using the immersion heater. The tank is getting power, and a heating engineer told me that he only changes elements at the householders risk, as occasionally the element wont come out without damaging the copper tank. Does this sound right, and approx what should it cost to change the element, or the tank and element? Thanks.
Changing the element is a DIYable job for a reasonably competent person. The damage to to tank is likely if you’re heavy handed. You should be able to disconnect the power supply to the element and test with a multimeter for continuity. That will rule it in or out as a probable cause,
RSstuff said:
Does this sound right...
Unfortunately, yes. I've done one a few times by tapping the spanner with a hammer for ages. The problem is the threads get corroded and copper is weak. ETA a modern tank will have far better insulation so it's not a bad thing to replace it The thermostats can get oversensitive and the overheat switch keeps triggering but I assume he's checked that. You can sometimes get away with turning the temperature down a little.
Have to agree with the likely damage, I have over the years changed 2 and the first which had been in use for 6 years came out after a struggle. The second one which I guess had been in the tank much longer would not shift, until it had caused a crack in the tank.
Approach with care and be prepared to replace a tank.
Approach with care and be prepared to replace a tank.
RSstuff said:
The large Immersion tank was installed around 15 years ago, and it hasn't worked in the 4 years we've lived in this house. As we have 16 solar panels on our roof, it would make sense for us to heat some of our water using the immersion heater. The tank is getting power, and a heating engineer told me that he only changes elements at the householders risk, as occasionally the element wont come out without damaging the copper tank. Does this sound right, and approx what should it cost to change the element, or the tank and element? Thanks.
I'd agree with the heating engineer on the risk of changing the immersion element in the tank - had exactly that problem - immersion failed (Hard water area) and so I drained down and tried to remove the element - the top of the tank started twisting - there was no way it was coming out easily. I purchased a new tank and element (the old one wasn't laggged so had a badly fitting puffer jacket round it and was 30 years old)Once I'd replaced the tank I had another go at removing the element and tore the tank at the boss mount so it was the right move to get a new tank and immersion.
I had to cut the top off the tank to weigh it in and the amount of scale inside was crazy
B'stard Child said:
RSstuff said:
The large Immersion tank was installed around 15 years ago, and it hasn't worked in the 4 years we've lived in this house. As we have 16 solar panels on our roof, it would make sense for us to heat some of our water using the immersion heater. The tank is getting power, and a heating engineer told me that he only changes elements at the householders risk, as occasionally the element wont come out without damaging the copper tank. Does this sound right, and approx what should it cost to change the element, or the tank and element? Thanks.
I'd agree with the heating engineer on the risk of changing the immersion element in the tank - had exactly that problem - immersion failed (Hard water area) and so I drained down and tried to remove the element - the top of the tank started twisting - there was no way it was coming out easily. I purchased a new tank and element (the old one wasn't laggged so had a badly fitting puffer jacket round it and was 30 years old)Once I'd replaced the tank I had another go at removing the element and tore the tank at the boss mount so it was the right move to get a new tank and immersion.
I had to cut the top off the tank to weigh it in and the amount of scale inside was crazy
megaphone said:
B'stard Child said:
RSstuff said:
The large Immersion tank was installed around 15 years ago, and it hasn't worked in the 4 years we've lived in this house. As we have 16 solar panels on our roof, it would make sense for us to heat some of our water using the immersion heater. The tank is getting power, and a heating engineer told me that he only changes elements at the householders risk, as occasionally the element wont come out without damaging the copper tank. Does this sound right, and approx what should it cost to change the element, or the tank and element? Thanks.
I'd agree with the heating engineer on the risk of changing the immersion element in the tank - had exactly that problem - immersion failed (Hard water area) and so I drained down and tried to remove the element - the top of the tank started twisting - there was no way it was coming out easily. I purchased a new tank and element (the old one wasn't laggged so had a badly fitting puffer jacket round it and was 30 years old)Once I'd replaced the tank I had another go at removing the element and tore the tank at the boss mount so it was the right move to get a new tank and immersion.
I had to cut the top off the tank to weigh it in and the amount of scale inside was crazy
When I cut the top off you could see the threads of the immersion were covered in limescale
I wonder how long it would take me to get my money back for a new tank and installation, by using solar generated electric to heat the water. Just to add the tank is lagged with bonded on insulation and we have a water softener, so that may help with removing the element.
Edited by RSstuff on Saturday 15th February 20:18
B'stard Child said:
megaphone said:
B'stard Child said:
RSstuff said:
The large Immersion tank was installed around 15 years ago, and it hasn't worked in the 4 years we've lived in this house. As we have 16 solar panels on our roof, it would make sense for us to heat some of our water using the immersion heater. The tank is getting power, and a heating engineer told me that he only changes elements at the householders risk, as occasionally the element wont come out without damaging the copper tank. Does this sound right, and approx what should it cost to change the element, or the tank and element? Thanks.
I'd agree with the heating engineer on the risk of changing the immersion element in the tank - had exactly that problem - immersion failed (Hard water area) and so I drained down and tried to remove the element - the top of the tank started twisting - there was no way it was coming out easily. I purchased a new tank and element (the old one wasn't laggged so had a badly fitting puffer jacket round it and was 30 years old)Once I'd replaced the tank I had another go at removing the element and tore the tank at the boss mount so it was the right move to get a new tank and immersion.
I had to cut the top off the tank to weigh it in and the amount of scale inside was crazy
When I cut the top off you could see the threads of the immersion were covered in limescale
start with electrical tests first.
It should have two thermostats - one is the regular one and should have a little dial on it to set the temperature - these can fail with a welded contact and stay on.
This is where the secondary safety thermal cutout kicks in and a little button pops out cutting the power and preventing bad stuff happening.
Both along with the heater itself can be tested with a multimeter if you understand what you are doing - otherwise get someone (not necessarily an electrician) to diagnose it before you spend money and risk changing the element
It should have two thermostats - one is the regular one and should have a little dial on it to set the temperature - these can fail with a welded contact and stay on.
This is where the secondary safety thermal cutout kicks in and a little button pops out cutting the power and preventing bad stuff happening.
Both along with the heater itself can be tested with a multimeter if you understand what you are doing - otherwise get someone (not necessarily an electrician) to diagnose it before you spend money and risk changing the element
The immersion element failed in my last house. Fortic copper combi tank, not cheap, so I didn't want to risk damaging it.
The element wasn't going to budge easily, so I drilled around the element, pulled the middle out, and carefully cut a slot in the male threaded part with a padsaw.
Once I got close to the cylinder boss threads, a few taps with a hammer and cold chisel split the fitting and loosened it enough to unscrew cleanly by hand.
The element wasn't going to budge easily, so I drilled around the element, pulled the middle out, and carefully cut a slot in the male threaded part with a padsaw.
Once I got close to the cylinder boss threads, a few taps with a hammer and cold chisel split the fitting and loosened it enough to unscrew cleanly by hand.
I once managed to damage the copper tank once while trying to remove an immersion...the copper is quite thin around the immersion heater boss on some tanks. I ended up having to drain the tank and solder up a split in the copper and it was a nightmare job.
Anyway, now I use the same method as Clockworks stated above.
Remove the wiring and the thermostat, use something like an 8mm drill to drill a line of holes that join up with each other. You can then insert a hacksaw blade into the slot you have made and then saw outwards towards the threads...your aim is to just saw until you can just see the threads. If you can saw 2 lines, so much the better. This will weaken the metal enough so that they come out much easier ...done loads like this and I generally just do it that way every time, before I've even tried to unscrew it normally. Fit a good quality one after...life is too short to mess about with cheap ones.
Anyway, now I use the same method as Clockworks stated above.
Remove the wiring and the thermostat, use something like an 8mm drill to drill a line of holes that join up with each other. You can then insert a hacksaw blade into the slot you have made and then saw outwards towards the threads...your aim is to just saw until you can just see the threads. If you can saw 2 lines, so much the better. This will weaken the metal enough so that they come out much easier ...done loads like this and I generally just do it that way every time, before I've even tried to unscrew it normally. Fit a good quality one after...life is too short to mess about with cheap ones.
I had just bought a house which fortunately we were going to refurb.
I went to the tank to drain it and as I touched the immersion it fell off as the tank was.so corroded.
But of shouting got my girlfriend upstairs asap as the only thing stopping a tank of water cascading down the stairs was me holding the immersion in place which mostly stopped the flow. Stuck a hose on it and then sat there with an aching hand waiting for the worst of it to drain.
I have sympathy with the plumber !
I went to the tank to drain it and as I touched the immersion it fell off as the tank was.so corroded.
But of shouting got my girlfriend upstairs asap as the only thing stopping a tank of water cascading down the stairs was me holding the immersion in place which mostly stopped the flow. Stuck a hose on it and then sat there with an aching hand waiting for the worst of it to drain.
I have sympathy with the plumber !
eliot said:
start with electrical tests first.
It should have two thermostats - one is the regular one and should have a little dial on it to set the temperature - these can fail with a welded contact and stay on.
This is where the secondary safety thermal cutout kicks in and a little button pops out cutting the power and preventing bad stuff happening.
Both along with the heater itself can be tested with a multimeter if you understand what you are doing - otherwise get someone (not necessarily an electrician) to diagnose it before you spend money and risk changing the element
If its fitted with a 3KW element the resistance can be checked and should read about 20 ohms, worth checking for continuity before removing, make sure the power is off first though.It should have two thermostats - one is the regular one and should have a little dial on it to set the temperature - these can fail with a welded contact and stay on.
This is where the secondary safety thermal cutout kicks in and a little button pops out cutting the power and preventing bad stuff happening.
Both along with the heater itself can be tested with a multimeter if you understand what you are doing - otherwise get someone (not necessarily an electrician) to diagnose it before you spend money and risk changing the element
I had an immersion tank that rusted at the base and started leaking through the kitchen ceiling, the new one that replaced it came with an element already fitted, think it cost about £500, the old one lasted about 18 years.
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