Electric Water Heater

nigelmercier

nigelmercier

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Live in Kent, boat in Canary Islands
www.bavariayacht.info
Following on from this thread. My electric water heater is not working. I've found a picture of what I thought was the top of the immersion heater:

017990a3a34aa8378df8dc6594fab779.jpg


However, it seems that this is in fact just the thermostat, see here, it is a Thermowatt RTS3.

I'm confused, because the thing that looks like this and screws into the large socket in my hot water cylinder at home is the heating element, it just has a thin plug-in thermostat.

Does anyone have any info on what I need to replace the heater and thermostat? Or perhaps some info on the hot water cylinder? Boat is a Bavaria 47, built in 2000.
 
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I'd guess that it's an immersion heater with a built-in, non-replaceable thermostat.

If the power feed goes directly to the two connections and nowhere else shown then it is.

Like you I am used to the type with a repleable thermostat but built-in ones do exist.

No reason not to replace it with a 'normal' one. IF the thread is standard, but you will not be able to tell until you extract it or find some manufacturer details of the tank.
 
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I think the heating element is under that thermostat, it should pull off, but there might be a screw on the side somewhere holding it in, then some more short wires going between the thermostat and the element
 
Right, just checked and the thermostat just pulls out of the heating element, so disconnect both wires on top, then just pull really hard and it will disconnect and slide out, its connected with 2 large spade connectors, and there are no wires underneath, then you can do your resistance checks on the stat and element to see which has failed
 
Well Nigel, you know who to contact if you need a new element ( Heat Rod ) - by the time you add the cost of the stat and seperate element the units supplied by Heat Rod look very attractively priced.
 
nigelmercier said:
The boat is in Tenerife, so I'm not able to test which has failed; I just want to buy a complete unit. I don't understand how the heater element attaches to this unit. I don't even know the make or even the size of the hot water cylinder.
Click to expand...
If it is just a thermostat the wires (well at least one of them) will connect to the heating element - just trace where they go - If they do not connect to anything else on the tank the heater is combined with the thermostat as suggested.

On a UK domestic heating element the thermostat, which is similar to your link image but with a smaller head, slides in through the top of the heating element.

Not much good for now unless you can get someone over there to check for you of course.
 
If that is the heater, then the exposed 230v terminals seem a bit worrying to me. Though the wires are the correct colours to be that...

Pete
 
prv said:
If that is the heater, then the exposed 230v terminals seem a bit worrying to me. Though the wires are the correct colours to be that...

Pete
Click to expand...

The wires arent normally exposed, there is a cover that goes over the whole lot that is either missing, or Nigel has removed.
 
Also, you'll probably find that the fault is just corroded spade connectors rather than a failed element or stat, if you remove the stat, clean the spades with some fine sandpaper or preferably a fiberglass brush (if you have one), then it will probably spring into life again.

I personally think its a very dodgy way of connecting a very high current load, it should use proper screwed connections
 
As TopDonkey said, it's a separate thermostat which just pulls off the heating element. I had one on my previous calorifier. There are no wires inside, just spade connectors (which are fine for the current involved). The thermostat obviously has to be used with a matching heating element, which has a long tube attached into which the thermostat's sensing rod fits. The last element I bought for mine came from a Volvo Penta dealer. The Thermowatt stat and element were used on Sigmar calorifiers, amongst others.

If you want to replace the whole lot, I think that the threaded fitting is common to most calorifiers, so you could probably get a different immersion element with integral thermostat cheaper than the items separately.
 
The thermostats and heating elements are all pretty common items for calorifiers as fitted to Bavarias. You should be able to source them easily at a chandlers for about £25 - 30 tops for both bits. The thermostat pulls off, the element unscrews (need a fairly large wrench to get it moving). The fun comes with all the water inside the calorifier; you need to drain it by uncoupling the feed pipe, which is usually on the bottom of the cylinder. If your Bavaira is anyting like mine, the access is difficult........ Have fun.
 
duncan99210 said:
The thermostats and heating elements are all pretty common items for calorifiers as fitted to Bavarias. You should be able to source them easily at a chandlers for about £25 - 30 tops for both bits.
Click to expand...
For a 2kw immersion heater? (+ stat) wow, which swindelery sells them for that price?
Standard 3kw domestic ones are cheap but as majority of shore power in marinas is limited to max 16amp a 3kw one would only leave 3~4 amp spare capacity - switch on the toaster or kettle at the same time and one trips the pontoon breaker not to mention the charger running at the same time - oops too much draw on the shore power.
 
nigelmercier said:
One of the issues to consider is that the heating element may react with the stainless steel cylinder. Any thoughts on this?
Click to expand...
The ones supplied by Heat Rod are either Incoloy or Stainless - can't comment on the cheapo "domestic" type elements though the one I took out of the HW tank in the house was copper (or copper alloy) in a copper tank.
 
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