Immersion problem

Hedgecutter

I have replaced the thermostat in my immersion for the third time in 7 years. after new one is in it only lasts a few weeks.

I have also replaced the whole immersion to see if that would sort the problem, but no.

Could there be another problem causing the thermostat to fail all the time? This one only lasted 3weeks.

It's is still coming on but switchs off after 10 minutes.

meercat

there are 3 sized thermostats
7 inch
11 inch
18 inch
are you replacing it with the right one

are you sure the immersion is wired correctly

meercat

if you can take a pic of the connections at the thermostat

turn power off before you do this

Hedgecutter

First time it went I got an electrician to replace it, next time I replaced the whole immersion and a few weeks ago I took out the thermostat took it to the trade shop got exact same and replaced it.

Not sure how to up load from iPad so can't put picutre up.

Bruthal

Maybe there is some other problem on the immersion circuit, a bad connection or problem with the switch, which is causing intermittent working of the immersion, and making you think its the stat.

Hedgecutter

robbie7730 wrote: »

Maybe there is some other problem on the immersion circuit, a bad connection or problem with the switch, which is causing intermittent working of the immersion, and making you think its the stat.

If there is power going to immersion would this eliminate the switch as a problem?

M cebee

depends how your checking power,you could be mistaken if using a phase tester
You can check the stat you took out in a pot of hot water

Hedgecutter

I can tell the temp of the tank because i have a solar panel and the controller lets me know the top and bottom temps of the tank.

Top temp is 40 deg and immersion stat is set to 65 deg, still not heating.

photo.JPG

Bruthal

Hedgecutter wrote: »

I can tell the temp of the tank because i have a solar panel and the controller lets me know the top and bottom temps of the tank.

Top temp is 40 deg and immersion stat is set to 65 deg, still not heating.

photo.JPG

If you had a multimeter, a test between the 2 terminals on the stat itself will tell you if the stat is open or closed.

230v will show on it if the immersion has power to it but the stat is open circuit, and causing the problem.

Bruthal

Hedgecutter wrote: »

If there is power going to immersion would this eliminate the switch as a problem?

How are you testing there is power at the immersion heater itself?

Hedgecutter

Im testing it with a phase tester, i have a multi meter but not sure how to test with it.

Bruthal

Hedgecutter wrote: »

Im testing it with a phase tester, i have a multi meter but not sure how to test with it.

Phase tester wont tell for sure that there is a sound live and neutral to the immersion.

But if you test at the stat terminals with it, if the stat is open circuit, the phase tester will light on one terminal of the stat (the one with 16A written beside it), or on the element ends that that terminal is connected to with the brown wire.

If the stat is closed as it should be (with water below 65c) then neither terminal of the stat will light the phase tester.

All assuming the immersion is connected properly.

Hedgecutter

robbie7730 wrote: »

Phase tester wont tell for sure that there is a sound live and neutral to the immersion.

But if you test at the stat terminals with it, if the stat is open circuit, the phase tester will light on one terminal of the stat (the one with 16A written beside it), or on the element ends that that terminal is connected to with the brown wire.

If the stat is closed as it should be (with water below 65c) then neither terminal of the stat will light the phase tester.

All assuming the immersion is connected properly.

I attached a picture above if you want to check the connections

Bruthal

Hedgecutter wrote: »

I attached a picture above if you want to check the connections

Yea but that doesnt tell us the blue in the flex is neutral.

But assuming blue is correctly the neutral, if stat is the problem causing the water not to heat, then one terminal will light the phase tester.

If the stat is closed as it should be, then neither terminal will light it.

If both terminals light the tester, then the neutral to the immersion possibly has a problem., or the overheat stat could be open.

Hedgecutter

robbie7730 wrote: »

Yea but that doesnt tell us the blue in the flex is neutral.

But assuming blue is correctly the neutral, if stat is the problem causing the water not to heat, then one terminal will light the phase tester.

If the stat is closed as it should be, then neither terminal will light it.

If both terminals light the tester, then the neutral to the immersion possibly has a problem., or the overheat stat could be open.

Think it might be the neutral alright, the phase tester lights up on both stat terminals and on the black wire and the brown but no light on the blue.

Bruthal

Hedgecutter wrote: »

Think it might be the neutral alright, the phase tester lights up on both stat terminals and on the black wire and the brown but no light on the blue.

If there is no lighting of phase tester on the blue, but there is on the stat both sides, then the overheat cutout seems to be the problem.

Hedgecutter

robbie7730 wrote: »

If there is no lighting of phase tester on the blue, but there is on the stat both sides, then the overheat cutout seems to be the problem.

Can that be replaced easy or do i have to replace immersion?

can you reset this cut off, very sunny on tuesday and tank hit 68deg with soalr panel would this have set the cutoff switch off.

Bruthal

Hedgecutter wrote: »

Can that be replaced easy or do i have to replace immersion?

It can be replaced easily if you can get one. I never went to get one before anyway, most immersions didnt seem to have them before from what i seen anyway.

Is the immersion heater at an angle into the cylinder, or dead level? Dead level can cause bubbles to get trapped under the head and so overheat, tripping the overheat stat. It would be unusual though.

Hedgecutter

robbie7730 wrote: »

It can be replaced easily if you can get one. I never went to get one before anyway, most immersions didnt seem to have them before from what i seen anyway.

can you reset this cut off, very sunny on tuesday and tank hit 68deg with solar panel would this have set the cutoff switch off.

Hedgecutter

robbie7730 wrote: »

It can be replaced easily if you can get one. I never went to get one before anyway, most immersions didnt seem to have them before from what i seen anyway.

Found a button on the over heat cutout switch, pressed it and of she took.

Solar panel heated the tank to max on tuesday 68deg and thats what set over heat off it (me thinks)

Thanks for your help robbie

Bruthal

Hedgecutter wrote: »

can you reset this cut off, very sunny on tuesday and tank hit 68deg with solar panel would this have set the cutoff switch off.

It shouldnt. The overheat stat should be well above the 65 the thermostat would be at. I dont think they would have a reset button, but should reset themselves when the cylnider cools down if it ever did trip.

Just test both sides of that overheat stat with your tester again. If it lights on one side but not the other, then it is that thats open circuited. Just make sure you are making contact with the terminals.

It is the item with the blue wire into it, and the brown wire out to the thermostat.

paddymick

Hedgecutter wrote: »

Found a button on the over heat cutout switch, pressed it and of she took.

Solar panel heated the tank to max on tuesday 68deg and thats what set over heat off it (me thinks)

This is why I would personally bypass the cutout,they cause more hassle than they are worth.

The same thing happens when the central heating system heats the cylinder to high..

Bruthal

Hedgecutter wrote: »

Found a button on the over heat cutout switch, pressed it and of she took.

Solar panel heated the tank to max on tuesday 68deg and thats what set over heat off it (me thinks)

Thanks for your help robbie

Yea i was tryin to see did it have a button. Couldnt see in photo. Anyway, its going now at least.

Hedgecutter

paddymick wrote: »

This is why I would personally bypass the cutout,they cause more hassle than they are worth.

The same thing happens when the central heating system heats the cylinder to high..

So should i just take the blue wire into the stat.

Bruthal

Hedgecutter wrote: »

So should i just take the blue wire into the stat.

Yea and remove the short brown one, if your going to bypass it. Id leave it myself for now, unless it keeps acting up. Most immersions i fitted didnt have them anyway.

paddymick

Hedgecutter wrote: »

So should i just take the blue wire into the stat.

Like I said that is just what I do personally because i have been to so many callouts with the same problem when there is no need for it to happen..

I think the tolerance in those cutouts is to low,Maybe if they where set a bit higher they might be a benefit but right now they are just a nuisance.

Im sure its against the manufacturers recommendations so I cant personally advice you to tamper with it.

Hedgecutter

robbie7730 wrote: »

Yea and remove the short brown one, if your going to bypass it. Id leave it myself for now, unless it keeps acting up. Most immersions i fitted didnt have them anyway.

Any idea what the cut off temp would be, i could set the max temp for the solar panel to be lower then immerasion.

DanWall

Note that due to the construction of the thermostat it will have different rising and falling values , if it switches off at 65 deg rising it will probably be about 55 deg falling before it switches on again,

Bruthal

Hedgecutter wrote: »

Any idea what the cut off temp would be, i could set the max temp for the solar panel to be lower then immerasion.

Not sure what it is. I would of thought it should be 85 to 90 degrees or just above if it was working properly.

Bruthal

DanWall wrote: »

Note that due to the construction of the thermostat it will have different rising and falling values , if it switches off at 65 deg rising it will probably be about 55 deg falling before it switches on again,

Well we would hope so, or else the thermostat would have a shorter life from switching on and off too often.

Hedgecutter

Thanks for the help lads.