Immersion heater stuck

[Norman_E]

I have to change the immersion heater in the calorifier. I have borrowed the correct spanner, but its stuck, having been fitted in with white hard setting goo. I have tried WD40, but cannot use heat due to fibreglass deck just above. Does anyone know a safe way to remove it, as excessive force simply tears the thin copper tanks (I did that to a domestic one).

 

[Bodach na mara]

I will be interested to hear if anyone has a good answer to this one.

You already know that brute force will result in destruction of the calorifier and have ruled out heat. Can you remove the calorifier so that you can use some heat? Even so, most of the ones I have seen have plastic foam insulation on them which restricts what you can do heat-wise.

I assume that the immersion heater is knackered, in which case destroying it is no loss. To break the grip between the sealant, try shock force, ie tapping with a drift and hammer in an anti-clockwise direction. TAPPING, not banging and with a SMALL hammer. This will also be easier if the calorifier is removed first.

 

[Alfie168]

You have no choice but to go for the tapping method outlined above by Wight Dawn. Its the only non destructive option. Remember "Little knocks can move great rocks where bigger knocks will break them".

That was told to me by very experienced engineer. Don't expect it to be quick, so lots and lots of patience. Rather than heat, why not use a freezing spray on the immersion head to contract it a bit. Can you place a hot water bottle on the calorifier? Anything to increase the expansion/contraction differential might help. Don't spray freezing spray on the calorifier of course (or your skin), so you need a thin tube nozzle and gloves.

Tim

 

[Cymrogwyllt]

Using a slate to insulate the deck from the heat wroks.

or something like

http://www.screwfix.com/p/rothenberger-plumber-s-soldering-mat/54910

 

[christhefish]

make sure you dont drain the tank until you have slightly loosened the element,try a small amount of pressure clockwise first ,then a sharp to anti clock wise should do the trick

 

[Norman_E]

Thanks for all the ideas. I have tried tapping it, to no avail. I am going to leave it to the end of the season as I can still have hot water via the engine. I will try the freeze spray then, plus a better spanner and slightly bigger hammer. The calorifier itself cannot be removed. The thing was installed before someone reduced the size of the deck hatch so that it would open wth the steering wheels in place! If I break it trying to remove the heater It will have to be cut up to get it out, and a smaller one put in.

 

[ProDave]

Try heat.

The heat from a gas blow lamp is very localised (on a small flame) and you can buy from a blumbers merchant, a flexible heat pad to protect close by areas from heat.

 

[philip_stevens]

Thanks for all the ideas. I have tried tapping it, to no avail. I am going to leave it to the end of the season as I can still have hot water via the engine. I will try the freeze spray then, plus a better spanner and slightly bigger hammer. The calorifier itself cannot be removed. The thing was installed before someone reduced the size of the deck hatch so that it would open wth the steering wheels in place! If I break it trying to remove the heater It will have to be cut up to get it out, and a smaller one put in.

The usual way a plumber mate of mine takes out stuck, duff immersions, is to remove the thermostat, and apply quite fierce heat into the middle of the immersion head. Then taps with a hammer on the immersion spanner. The tank must remain almost full to be able to stop rotating when the spanner is hit, and to dissipate heat to the rest of the tank and insulation. I quite often work with him, so have seen how it is done - including the one in our house.

 

[Norman_E]

Good idea. When I finish sailing in October I will try to move the tank to a point beneath the hatch, then use a blowlamp. I can probably borrow one here as this marina is full of friendly people, and a lot of liveaboards who have lots of useful kit.

 

[mjf107]

Good idea. When I finish sailing in October I will try to move the tank to a point beneath the hatch, then use a blowlamp. I can probably borrow one here as this marina is full of friendly people, and a lot of liveaboards who have lots of useful kit.

If all else fails you may be able to cut the washer away with a broken hacksaw blade or Dremel, this has the effect of reducing the surface contact area and consequently the force needed to break the joint. I've had success using this method in domestic situations, presumable immersion heaters fitted into calorifier use the same type of washers, If the sealant is in the threads you may still need to use heat/cold as others have suggested ….......good luck patience is the key.........

 

[fergie_mac66]

Drill

I had an Immersion heater(household though)That would not come out tried everything what removed it was drastic but got it out with no damage to tank.I drilled a row of 5 mm holes across the middle of heater then joinined all the holes together with ceka side cutting drill bit just missing the threads . Then squeezed the 2 halves together with large molegrips separating the threads .Took about 15 mins .Cleaning the threads on the tank from the plumbers mate was the hard bit !