Fitting an immersion heater

[RichM]

I don't have an immersion heater on my boat and until today I thought it necessitated replacing the calorifier to fit one, a job I didn't want to splash out on! However, I decided to remove my rear steps to inspect my existing 16 year old calorifier and noticed that it has what appears to be a blanking plate for an immersion heater. 

Can anyone confirm if this is indeed the case?

If so, is it just a case of fitting a 1KW immersion heater once drained/blanking plate removed? I have nearby access to a 240v socket that is isolated from the inverter, I imagine this would be suitable? How does the immersion heater know once it has reached temperature? Does it automatically regulate and cut out?

Here's what I am looking at on Midland:
https://www.midlandchandlers.co.uk/store/category/1624/product/hc-044.aspx

Cheers

RichM

 

 

[mrsmelly]

Yep just remove blank and fit. the heater will have a dial to set usualy 1 to 5 and will self regulate. I havnt opened your midland swindlers link but try Limekiln they are always cheaper.

Edited September 3, 2017 by mrsmelly

[rusty69]

Thats what I did with one i bought off fleabay. Had a blanking plug similar to pic. I put a 1Kw immersion in. 

[WotEver]

1 minute ago, RichM said:

How does the immersion heater know once it has reached temperature? Does it automatically regulate and cut out?

Yes, the heater has a stat. They can fail so it's not a bad idea to wire it in series with a tank stat for belt and braces. 

[RichM]

Thanks all. Do they usually come supplied with wiring?

[mrsmelly]

3 minutes ago, RichM said:

Thanks all. Do they usually come supplied with wiring?

No.

[WotEver]

And use heat resistant cable. Available all over the place - even B&Q. 

[RichM]

Thanks again all.

Does anyone know if it should be cheaper than using an Eberspacher to heat water?

[rusty69]

Just now, RichM said:

Thanks again all.

Does anyone know if it should be cheaper than using an Eberspacher to heat water?

I would think so, unless your electric costs are high

[Drayke]

Much quieter. 

[colinnorth]

Although I cannot see it clearly stated, I assume the proposed immersion heater will only be used when on shore power or 240v independent generator?

[RichM]

34 minutes ago, colinnorth said:

Although I cannot see it clearly stated, I assume the proposed immersion heater will only be used when on shore power or 240v independent generator?

Yes, indeed.

[AndrewIC]

Modern immersion heaters have two thermostats, wired in series with the element. One is adjustable and is set to the desired temperature and opens and closes as the temperature rises and falls. The other is for safety and is set to a higher temperature (and on mine had a sticker over the dial). This one opens if the temperature exceeds the safety limit, and does not reclose, it needs a manual reset.

On mine, the safety stat needed tweaking upwards a bit, because after a good thrash the engine heated the water to a temperature which caused it to trip. This wasn't apparent until the next time the immersion was used and found inoperative!

[RichM]

Thanks again

I figure removing the blanking plate itself might be easier said than done given the age of the calorifier. (16 years) What's the best tool for the job? 30mm socket wrench? Pipe wrench? Or will I likely encounter the same problem with those?

Cheers

[nbfiresprite]

7 minutes ago, RichM said:

Thanks again

I figure removing the blanking plate itself might be easier said than done given the age of the calorifier. (16 years) A gas spanner (30mm?) seems to fit on to the blanking plate but it won't loosen it.

What's the best tool for the job? Would a stilson style pipe wrench do it or will I likely encounter the same problem? 

Cheers

Did you remember to dipresureise the calorifier first?. limescale does buld up over, so lightly tap around the edge of the blanking plate to losein it, 30mm socket is best to use to remove it. A length of pipe on the socket wrench will give more leverage. As a last resort take the calorifier out and blank off the outlet pipe, turn upside down and pour in a few pints of cheap vinegar. give a good shake and leave for a few hours, by which time the vinegar will have soften the limescale, once the blanking plate is off, give the inside a good rinse out. It may take a few hours, but it is still better than paying for a replacment calorifier.       

[Robbo]

5 hours ago, RichM said:

Thanks again all.

Does anyone know if it should be cheaper than using an Eberspacher to heat water?

Diesel is around 10kwh per litre, electric is. 1kwh per unit.   The Ebersputtrr would be around 90% efficient and the electric is 100%.  The Ebersplutter uses electric as well ofcourse lowering its efficiency further, then you have service costs.    So on paper the ebersplutter is prob ahead due depending on your diesel costs.  If it’s around the £1 per litre mark, and you get electric at 12p/unit then that’s prob about even point.

however with electric it good for peaceful heating, better at keeping it hot if wanting heat all day as it can cycle with no issue, etc. So can be just left on.

Edited September 4, 2017 by Robbo

[nicknorman]

90% efficiency for an Eber sounds very optimistic to me.

im sure that when all factors are taken into account, the immersion is much cheaper.

[Flyboy]

10 hours ago, RichM said:

Thanks again all.

Does anyone know if it should be cheaper than using an Eberspacher to heat water?

When you fit the immersion why not sort out that top connection (marked A), it looks like the pipe is in at an angle and straining the fitting. A possible future leak scenario.

[MtB]

9 hours ago, RichM said:

Thanks again

I figure removing the blanking plate itself might be easier said than done given the age of the calorifier. (16 years) A gas locker wrench (30mm?) seems to fit on to the blanking plate but it won't loosen it.

What's the best tool for the job? Would a stilson style pipe wrench do it or will I likely encounter the same problem? 
Cheers

 

Assuming your Calor spanner is a good fit then just give the end of the spanner a good hard whack with a claw hammer or club hammer. Just to loosen it and break the seal 

Do this with the tank FULL of water though, and ideally very hot too. Don't try it when drained, you'll split the tank. 

Once you've cracked the joint and moved it, it probably still won't leak any water until you've rotated it about 90 degrees, but if it does, hand tighten it again. 

Now drain down, remove the plug and fit your heater element, and re-fill test and wire it up. 

1 hour ago, nicknorman said:

90% efficiency for an Eber sounds very optimistic to me.

im sure that when all factors are taken into account, the immersion is much cheaper.

 

Surely that depends on the price being paid for the leccy, which varies widely and hasn't been mentioned yet. 

[Ex Brummie]

If the plug is scaled in, then a sharp tap to tighten it often helps to break the seal before unscrewing. Always loosen with the cylinder full, only emptying it when there is no resistance. Is your calorifier horizontal with the plug at the top?

Posted whilst MTB was replying in the same tone.

Edited September 4, 2017 by Ex Brummie

[MtB]

14 minutes ago, Ex Brummie said:

If the plug is scaled in, then a sharp tap to tighten it often helps to break the seal before unscrewing.

 

I'm inclined to disagree with this bit. If a sharp tap is going to break the 'stiction', it might as well be in the direction of loosening it. I see no upside in tightening it further, only downside!

[nicknorman]

23 minutes ago, Mike the Boilerman said:

 

Surely that depends on the price being paid for the leccy, 

Isn't it unlawful to mark up electricity unit costs? They can add a charge for the infrastructure but that is normally based on calendar time rather than units consumed. But yes, I'm sure there are folk around who don't mind breaking the law to make a few quid.

of course it depends on how you factor in the capital cost of the Eber. If you assign all the cost to heating the radiators and none to heating the water on the basis that you need to have the unit anyway for central heating, that will make a big difference (cheating, though!). Bearing in mind the likes of Ebers' dislike for short cycling, I think using it to heat water when not heating the radiators is likely to cause significant maintenance costs.

for me, the lack of fuss when using an immersion vs a diesel heater would make it worth it even if it were slightly more expensive (which I don't think it is).

[MtB]

Just now, nicknorman said:

Isn't it unlawful to mark up electricity unit costs?

 

It is, but plenty of evidence here that it still happens. 

The problem is who to raise it with, apparently. When it happens to you, you make a complaint to the regulator and nothing happens. Radio silence IIRC. So you pay up or change moorings.  OR, you make a complaint and your moorings agreement gets terminated so peeps are reluctant to make an issue of it.

But in addition tariffs vary hugely. The boater actually has no idea what price is being paid by the moorings provider unless they choose to fess up. So how would they know?

[MtB]

6 minutes ago, nicknorman said:

for me, the lack of fuss when using an immersion vs a diesel heater would make it worth it even if it were slightly more expensive (which I don't think it is).

 

I very much agree with this though. Using an Ebasto to heat water is plain daft. Either a Morco or use the shoreline if on your mooring. 

Lots of peeps run their engine though, which I think is pure bad manners done regularly. I accept some do this for a couple of hours to heat the water and charge the batteries daily, which some here hold is necessary. 

[WotEver]

2 minutes ago, Mike the Boilerman said:

charge the batteries daily, which some here hold is necessary. 

They'd be the ones whose batteries last more than a couple of months I guess?