Emersion heater problem

Peter256

A few months back the mains power switch started to trip when switching on emersion. I got a plumber to change the emersion element and this solved the switch trip problem.
But the new emersion wasn't heating the tank properly even after leaving it on for an hour or two the hot water would run out quickly and the tank seemed to be only hot at the top with the middle of tank been barely warm. The old emersion would heat the water in less time maybe 40 minutes and the hot water would last longer.
Anyway I told the plumber that about the new emersion not working properly and he he said I would need to leave it on for longer 2 hours at least which I never had to do with the old emersion, anyway there still wasn't enough hot water after leaving it on for the 2 hours. So the plumber has now changed the element again incase the other one was faulty but it's the same only heating the top of the tank. He said if it doesn't work this time then it's a tank problem. The stove boiler heat's the tank no problem and I don't think there is a problem with the tank.

punisher5112

Is there a switch for bath/sink if not then this is the issue and also the elements thermostat may well need to be adjusted.

It sounds like it's heating on the sink element which would only heat the top section.

Wearb

Is the immersion element the same length as the old one?
Vertical immersion?

Peter256

punisher5112 wrote: »

Is there a switch for bath/sink if not then this is the issue and also the elements thermostat may well need to be adjusted.

It sounds like it's heating on the sink element which would only heat the top section.

It has a switch for sink/bath and I have it on bath. The power switch is giving power unless the bath/shower switch has stopped working and is only heating on sink. The plastic surround on both switches does have a slight crack which has been like that a long time now. But this was never an issue for the old element. The element thermostat is adjusted so it wouldn't be that. Maybe I could get the switches changed, I just don't want spend more money and still have same problem.

Peter256

Wearb wrote: »

Is the immersion element the same length as the old one?
Vertical immersion?

Yeah the emersion is same length. I wonder is it possible the sink/bath switch has stopped working and is only heating on sink. It's a double switch with a power and sink/bath. The power swit is definitely working.

meercat

I’d say the plumber hasn’t wired the immersion correctly.if he followed the existing wiring when he changed the first immersion then the chances are it’s incorrect as new color codes were introduced.

Check if the meter changes speed whilst switching from sink to bath. No deviation will confirm this

Wearb

Peter256 wrote: »

Yeah the emersion is same length. I wonder is it possible the sink/bath switch has stopped working and is only heating on sink. It's a double switch with a power and sink/bath. The power swit is definitely working.

Try it on sink, perhaps wiring reversed.

punisher5112

Cable mix up, switch to sink and see.

Peter256

meercat wrote: »

I’d say the plumber hasn’t wired the immersion correctly.if he followed the existing wiring when he changed the first immersion then the chances are it’s incorrect as new color codes were introduced.

Check if the meter changes speed whilst switching from sink to bath. No deviation will confirm this

I have just checked the metre and when the bath/sink switch is switched to sink the meter is going faster so I take it as yourself and the other lads on here have said the wiring for that switch must be wrong.

Peter256

punisher5112 wrote: »

Cable mix up, switch to sink and see.

Yeah I am trying that now. I think that might be the problem because when I checked the meter it was spinning faster on sink.

John.G

Another way to confirm it, with a lukewarm cylinder the (true) sink element will heat up the water to cut out point in 30 minutes or so, the disc will stop spinning rapidly then, if it had (has) been selected to the (true) bath element, the disc will continue to spin for approx twice this length of time. Some immersions, depending on element length have the same power output in both elements so impossible to check via the disc method but as you are happy that one is spinning faster than the other then you should be ok, if satisfied then and if you don't want to be getting your installer back, just re label the Sink/Bath.

PatrickSmithUS

Get rid of it.

Talk to the bank and apply for a grant to get a solar powered thermal water heater fitted to the ceiling.

We never bother with the immersion any more. If the oil heating doesn't heat the tank then there's plenty from the thermal heater for days.

Peter256

John.G wrote: »

Another way to confirm it, with a lukewarm cylinder the (true) sink element will heat up the water to cut out point in 30 minutes or so, the disc will stop spinning rapidly then, if it had (has) been selected to the (true) bath element, the disc will continue to spin for approx twice this length of time. Some immersions, depending on element length have the same power output in both elements so impossible to check via the disc method but as you are happy that one is spinning faster than the other then you should be ok, if satisfied then and if you don't want to be getting your installer back, just re label the Sink/Bath.

I did say yesterday that I thought the problem might be the sink/bath switch because after switching it to sink the meter seemed to spin faster. But after leaving the emerson on for another 2 hrs (3 hrs total) the cylinder was still not fully hot with the middle been still only lukewarm. And when I checked the meter and switched back to bath the meter went faster on bath this time which puzzled me but I think the it must be that the speed change I am seeing only happens at first when you switch between sink and bath but then the meter must settle to a slower speed then for both sink and bath. Anyway after 3 hours even if the first hour I had it on sink, I'd expect to have at least half the tank or more hot but this didn't happen so I still have the same issue.

Wearb

At this stage I'd need a look at the wiring to see if I can spot a problem. Also if I was there I'd measure the resistance across the elements.

John.G

Peter256 wrote: »

I did say yesterday that I thought the problem might be the sink/bath switch because after switching it to sink the meter seemed to spin faster. But after leaving the emerson on for another 2 hrs (3 hrs total) the cylinder was still not fully hot with the middle been still only lukewarm. And when I checked the meter and switched back to bath the meter went faster on bath this time which puzzled me but I think the it must be that the speed change I am seeing only happens at first when you switch between sink and bath but then the meter must settle to a slower speed then for both sink and bath. Anyway after 3 hours even if the first hour I had it on sink, I'd expect to have at least half the tank or more hot but this didn't happen so I still have the same issue.

Strange as it may seem but your set up might be OK.

If you start with a cold cylinder and heat up the top half (approx 30/40 litres) until the thermostat cuts out and then change over immediately to the bath element it is more than likely that no more heating will take place as the thermostat rod doesn't extend further than the bottom of the say 11 ins sink element so it will not detect the colder water below this unless you start running some hot water off.
So to rule out this I would suggest running off most of the cylinder hot water (stove off) then switch on the normal bath and occasionally look at the spinning disc, if it is still spinning after 50/60 minutes or so then that is a reasonable indication that it is the bath element but also if someone has set the thermostat to say 40/45C then the element will cut off after maybe 45/60 minutes and the cylinder will never get hot, these stats are normally pre set to 65C (for health reasons) of course the sink element will also only give water at the same 40/45C if stat has been set to this.

Wearb's suggestion above is probably the way to go but you may not have a m.meter, however if you are willing just to take a photo of the immersion top with the cover removed then that will tell a lot, ensure that the MCB & the Main switch are off before removing&replacing the cover, if you do this you are quite safe to take a photo or two.
Your picture should look very like the attached.

You might do this if happy to do so before anything else.

punisher5112

Mine went there last week or two and have it now she can get a shower out of the sink one, so it should hopefully save me money, also the electric shower the daughter uses does be on up to an hour, just need to sort her and I'll be rolling in the savings.

Peter256

punisher5112 wrote: »

Mine went there last week or two and have it now she can get a shower out of the sink one, so it should hopefully save me money, also the electric shower the daughter uses does be on up to an hour, just need to sort her and I'll be rolling in the savings.

How long does it take for your emersion to heat the tank fully ?
According to the electric Ireland website it states that sink should take 50 minutes and bath 2.5 hour's.
I had my new emersion on for 3 hours last night and the tank was still only hot at the top, this was after trying it 1 hour on sink and 2 hours on bath, as I thought it might be a switch fault.

meercat

Can you post a photo of the switch connections

Blue-neutral
Black-sink
Brown-bath

punisher5112

Peter256 wrote: »

How long does it take for your emersion to heat the tank fully ?
According to the electric Ireland website it states that sink should take 50 minutes and bath 2.5 hour's.
I had my new emersion on for 3 hours last night and the tank was still only hot at the top, this was after trying it 1 hour on sink and 2 hours on bath, as I thought it might be a switch fault.

I would say around the 2 hours maybe less actually, cylinder wouldn't be the biggest either.
When the hearing is on I have a nest so I can have the temp set for specific times and there is no option for the cylinder the way the heating is set up, obviously I can fit units etc to change this.

Peter256

John.G wrote: »

Strange as it may seem but your set up might be OK.

If you start with a cold cylinder and heat up the top half (approx 30/40 litres) until the thermostat cuts out and then change over immediately to the bath element it is more than likely that no more heating will take place as the thermostat rod doesn't extend further than the bottom of the say 11 ins sink element so it will not detect the colder water below this unless you start running some hot water off.
So to rule out this I would suggest running off most of the cylinder hot water (stove off) then switch on the normal bath and occasionally look at the spinning disc, if it is still spinning after 50/60 minutes or so then that is a reasonable indication that it is the bath element but also if someone has set the thermostat to say 40/45C then the element will cut off after maybe 45/60 minutes and the cylinder will never get hot, these stats are normally pre set to 65C (for health reasons) of course the sink element will also only give water at the same 40/45C if stat has been set to this.

Wearb's suggestion above is probably the way to go but you may not have a m.meter, however if you are willing just to take a photo of the immersion top with the cover removed then that will tell a lot, ensure that the MCB & the Main switch are off before removing&replacing the cover, if you do this you are quite safe to take a photo or two.
Your picture should look very like the attached.

You might do this if happy to do so before anything else.

I have took a few pictures, one of the emerson and one of the actual switch which has a crack in it a long time now I am not sure if this would cause the issue as there is still power going from it.
Actually i don't think it's allowing me to attach the pics, it's saying file is too large.

Peter256

meercat wrote: »

Can you post a photo of the switch connections

Blue-neutral
Black-sink
Brown-bath

I took a pic and tried attaching it to this post but it's saying too large of file.

John.G

The file I posted of a immersion above is 2.77 MB and is a .jpg file (whatever that is), I think you should be able to upload up to a 5 MB file. Are you trying to attach just one at the time?.

Peter256

John.G wrote: »

The file I posted of a immersion above is 2.77 MB and is a .jpg file (whatever that is), I think you should be able to upload up to a 5 MB file. Are you trying to attach just one at the time?.

Ok I will try it again the pic was over 5 mb but I compressed it to around 2 mb now.

meercat

Peter256 wrote: »

Ok I will try it again the pic was over 5 mb but I compressed it to around 2 mb now.

Can you unscrew the switch and post a photo of the connections. The immersion comes prewired so I’d expect the problem to be at this switch end

Blue-neutral
Brown-bath
Black-sink

Peter256

meercat wrote: »

Can you unscrew the switch and post a photo of the connections. The immersion comes prewired so I’d expect the problem to be at this switch end

Blue-neutral
Brown-bath
Black-sink

I took a few pics of switch, I pulled bit out as far as I could to get a view of the wiring. There was 2 litter pieces of timber in the switch cavity I'm not sure if they were ment to be there. Anyway I have attached the pics. I am not sure if you will be able to see the wiring clearly.

John.G

The switch could certainly do with renewing but the wiring may still be OK, if you have a phase tester I can show you how to check out everything from the immersion top, just replace the switch for the moment, if everything checks out then you can get the switch renewed with the wiring as is later.

meercat

Peter256 wrote: »

I took a few pics of switch, I pulled bit out as far as I could to get a view of the wiring. There was 2 litter pieces of timber in the switch cavity I'm not sure if they were ment to be there. Anyway I have attached the pics. I am not sure if you will be able to see the wiring clearly.

It’s wired incorrectly according to your picture
Is there a joint box connecting your new immersion to your existing switch.
My advice is to get a new immersion switch and connect
Blue-neutral
Brown-bath
Black-sink

Or get an electrician.

Peter256

meercat wrote: »

It’s wired incorrectly according to your picture
Is there a joint box connecting your new immersion to your existing switch.
My advice is to get a new immersion switch and connect
Blue-neutral
Brown-bath
Black-sink

Or get an electrician.

Is this the joint box you are taking about in attached pic ?

Peter256

John.G wrote: »

The switch could certainly do with renewing but the wiring may still be OK, if you have a phase tester I can show you how to check out everything from the immersion top, just replace the switch for the moment, if everything checks out then you can get the switch renewed with the wiring as is later.

I do have a voltmeter, would that be able to check if the the sink/bath switch is heating the element correctly ?.
As I said in my first post when I told the plumber about the problem he replaced the new element he put in with another new one incase the first one was faulty he said. Would he not have been able to check the first new element with a voltmeter to see if it was good and working correctly ?

John.G

Yes I will send a little sketch shortly.

John.G

You will have to drain down a fai bit of water to test both the sink and the bath.
If its a multimeter you have you can also check the resistance of each element even though very unlikely any problems there.

Resistance Check: (can be done while draining off say 40/50 litres of hot water.)
Ensure power off to immersion, change m.meter to 0 to 200 ohm scale or similar
take readings between 1 and 5 and then between 2 and 5.

When water drained down, restore power to immersion and select Sink, change m.meter to 500v ac and check for voltage across 1 and 3 and 1 and 4.

Change to Bath and carry out same voltage check across 2 and 3 and 2 and 4.

Cerco

I think you should get an electrician to replace the switch and get rid of that joint box. If a joint box is necessary, due to insufficient cable length, then it should be installed properly.

Peter256

John.G wrote: »

You will have to drain down a fai bit of water to test both the sink and the bath.
If its a multimeter you have you can also check the resistance of each element even though very unlikely any problems there.

Resistance Check: (can be done while draining off say 40/50 litres of hot water.)
Ensure power off to immersion, change m.meter to 0 to 200 ohm scale or similar
take readings between 1 and 5 and then between 2 and 5.

When water drained down, restore power to immersion and select Sink, change m.meter to 500v ac and check for voltage across 1 and 3 and 1 and 4.

Change to Bath and carry out same voltage check across 2 and 3 and 2 and 4.

Thanks for that. I just have a few questions.
For the resistance test I need to drain 40 or 50 litres and the other tests I need to have the tank fully drained ?
When I am doing the tests for example between 1 and 5 which number gets the red probe and which the black ?
It will probably be tomorrow when I try this.

John.G

The resistance tests can be done with a hot or cold cylinder, I only suggested you did it while draining down to save time. It doesn't matter which probe is on the 1 or 5, just make sure that the power is off.
You may have to drain down a bit more than the 40/50 litres if the cylinder is "full" of hot water, the quickest way may be with the immersion turned on...on the sink and keep a eye on that meter disc, when it starts spinning rapidly then you can stop draining down to carry out those power tests.

Wearb

John is asking you to turn on a hot tap so that the hot water is replaced with cold in the cylinder.
I say that for clarity as often a drain down would suggest emptying all or some water from it.

meercat

Peter256 wrote: »

Is this the joint box you are taking about in attached pic ?

Yes.

Your immersion is incorrectly wired according to the photos you’ve provided

John.G

It should have been a simple 3 wire like my one still in service but a bit awkward to change over sink/bath as the c/o switch is in the top of the immersion.

Peter256

meercat wrote: »

Yes.

Your immersion is incorrectly wired according to the photos you’ve provided

Is it the switch that is incorrectly wired or the element ?

John.G

Just saw your 1245 post there but it has disappeared,
yes, just run off the water from the hot tap, the immersion 0n/off switch should be ok while removing/replacing the cover, just keep you fingers away from the terminals, power on/off refers to the on/off immersion switch.

Peter256

John.G wrote: »

Just saw your 1245 post there but it has disappeared,
yes, just run off the water from the hot tap, the immersion 0n/off switch should be ok while removing/replacing the cover, just keep you fingers away from the terminals, power on/off refers to the on/off immersion switch.

The last part I do with the emerson on, will that be safe ?

punisher5112

Peter256 wrote: »

The last part I do with the emerson on, will that be safe ?

I would power off when removing lid or that in case cable is loose.

Don't want to be getting a shock.

I would say the cable was just put on wrong terminal on immersion head connection.

John.G

Yes, quite safe, a long as you have the M.meter set to 500V AC (on/off switch ON) and obviously don't touch any of the immersion terminals, the resistance test must be done (to avoid damage to your m.meter) with the power off (on/off switch OFF).

Peter256

John.G wrote: »

Yes, quite safe, a long as you have the M.meter set to 500V AC (on/off switch ON) and obviously don't touch any of the immersion terminals, the resistance test must be done (to avoid damage to your m.meter) with the power off (on/off switch OFF).

I have done the resistance test and got a zero reading which I think might be good ?
But when I did the second part it also giving zero which I don't think is what we are looking for ?
Maybe for second part I have voltmeter set wrong. I have attached pic.

John.G

Forget about the resistance check just now, will come back to it.

Change the meter to 600 scale to the right of the OFF and take your readings (Immersion on/off switch ON)

Peter256

John.G wrote: »

Forget about the resistance check just now, will come back to it.

Change the meter to 600 scale to the right of the OFF and take your readings (Immersion on/off switch ON)

I have done that now and the only one I am getting a reading from is 2 - 3 which is 096.

John.G

OK just checking...... you have ran off enough hot water to get the disc spinning rapidly? with on/off switch ON and SINK selected??, if not spinning rapidly change to BATH and check for spinning.
Irrespective of whether it is spinning or not ensure on/off swich ON and check all readings with SINK selected then BATH, also is the on/off neon light ON with the on/off switch ON??.

Peter256

John.G wrote: »

OK just checking...... you have ran off enough hot water to get the disc spinning rapidly? with on/off switch ON and SINK selected??, if not spinning rapidly change to BATH and check for spinning.
Irrespective of whether it is spinning or not ensure on/off swich ON and check all readings with SINK selected then BATH, also is the on/off neon light ON with the on/off switch ON??.

Yes I have done everything, the meter is spinning quickly when I switch on the emersion.
And I have checked the readings as per your pic you sent me back of my emersion with numbers.
I have checked 1 - 3 and 1 - 4 with emerson power on and at sink.
And I have checked 2 - 3 and 2 - 4 with power on and at bath.

John.G

Thats very strange, with sink selected you should have got 230 to 240 v between 1&3, 1&4 and 1&5, even if you are only getting 96V you should get that on 1&3, 1&4 and 1&5. You are also saying that even with the disc spinning on BATH that you are getting 0V on those checks??, with bath selected do the checks on on 1&3, 1&4 and 1&5 and see what the readings are, if still only 96v on whatever reading change the meter scale to 200 just to the right of the 600 just to verify that you are still only getting 96V.

Also with Sink then Bath selected check voltage betwee 1 and the earth terminal (the yellow and green wire) on both the 600v scale and the 200v scale.

Peter256

John.G wrote: »

Thats very strange, with sink selected you should have got 230 to 240 v between 1&3, 1&4 and 1&5, even if you are only getting 96V you should get that on 1&3, 1&4 and 1&5. You are also saying that even with the disc spinning on BATH that you are getting 0V on those checks??, with bath selected do the checks on on 1&3, 1&4 and 1&5 and see what the readings are, if still only 96v on whatever reading change the meter scale to 200 just to the right of the 600 just to verify that you are still only getting 96V.

Also with Sink then Bath selected check voltage betwee 1 and the earth terminal (the yellow and green wire) on both the 600v scale and the 200v scale.

I only checked 1 and 5 in the resistance test as you told me yesterday.
You told be yesterday check 1 and 3, 1 and 4 with power on and sink selected.
And you said check 2 and 3, 2 and 4 the with set to bath.
So the reading I got of 96 volts was in 2 and 3 (power on/bath).

John.G

OK yes correct I got a bit mixed up .....with BATH selected you should get 230/240V between 2&3, not 96V, and with SINK selected you should get the same between 1&3 but your are getting 0V? Can you please do those tests again but with the black probe on the earth terminal.

meercat

Peter256 wrote: »

Is it the switch that is incorrectly wired or the element ?

The switch is not wired correctly