help finding immersion boss

[paulmellors]

as a newbie, I'm looking for help identifying an immersion boss on my calorifier.

 

I don't know for certain that there is one but Leigh Guest at Thorne Boat Services has said it is very likely that there will be one seeing as it's less than 10 years old.

 

I have been instructed to look for likely areas under the insulation and then remove it with a stanley knife. Any suggestions as to which part looks favourite greatly appreciated.

 

Thanks

 

Paul

 

Calorifier by rainbowconnection_pics, on Flickr

 

 

 

Calorifier by rainbowconnection_pics, on Flickr

Calorifier by rainbowconnection_pics, on Flickr

 

[keble]

Hi Paul, it doesn't look like mine - here's a photo with immersion fitted:

 

 

 

 

ETA 2nd photo which shows immersion cover removed. I can't see this kind of housing in your photos Paul

Edited April 10, 2013 by keble

[blackrose]

That looks like it to me, under this lump of insulation.

 

Calorifier by rainbowconnection_pics, on Flickr

Cut the insulation off that area with a knife to get a better look. You can always use a can of hand-held sprayfoam to re-insulate the area if it's the wrong one.

Edited April 10, 2013 by blackrose

[Ark Right]

 

Hi Paul

 

You will find it below the lump of insulation in this photo, you will also find that the sealing plug for the immersion boss has been or still is leaking.

A

 

 

Calorifier by rainbowconnection_pics, on Flickr

[paulmellors]

Thanks so much for the quick replies. Really helpful. Am I correct in thinking tat the mid tank option would be the better choice, if there are in fact 2 boss'?

 

Unless there's any reason that this is a complex job, I'm thinking of attempting it. The 240v consumer unit has only 2 trips, which are both used, so it seems to me the simplest and tidiest option would be to replace that unit with a 4 way unit.

[ditchcrawler]

 

 

Hi Paul

 

You will find it below the lump of insulation in this photo, you will also find that the sealing plug for the immersion boss has been or still is leaking.

A

 

 

Calorifier by rainbowconnection_pics, on Flickr

I think this is the ONLY one

[blackrose]

I think this is the ONLY one

Mine looked more like the other lump before I got the insulation off.

 

Thanks so much for the quick replies. Really helpful. Am I correct in thinking tat the mid tank option would be the better choice, if there are in fact 2 boss'?

 

Unless there's any reason that this is a complex job, I'm thinking of attempting it. The 240v consumer unit has only 2 trips, which are both used, so it seems to me the simplest and tidiest option would be to replace that unit with a 4 way unit.

You'll need an immersion spanner. Retighten the immersion heater once you've refilled the tank and the tank has warmed up.

Edited April 10, 2013 by blackrose

[BEngo]

Mine looked more like the other lump before I got the insulation off.

 

You'll need an immersion spanner. Retighten the immersion heater once you've refilled the tank and the tank has warmed up.

 

Don't force the plug when undoing it- you will distort the tank if you do.

 

Don't use ordinary PTFE tape when replacing- it doesn't seem to like threads as big as an immersion and leaks. Use either the thicker ptfe tape for gas, and lots of it or Boss White and hemp. I suppose Fernox LS1 might do but I always thing that stuff is a bodgers gift.

 

N

[ditchcrawler]

An immersion heater SHOULD seal with nothing on the thread as it has a gasket or jointing material between the faces. A smear of boss white on the flange joint.

[paulmellors]

The good news is that there is a single boss on the side of the tank as suggested. It's going to be tight for clearance because there is only 2 1/2" from the top of the blanking plate to the bed.

 

The mattress sites on loose slats (one can be seen in the pic), so I'm thinking that the immersion can fit between the slats and maybe a piece of heat resistant something or other across the slats.

 

Once again, thanks for all advise and help so far.

 

Paul

[the grinch]

as i said on FB its likely that your tank has an 11" and a 27" boss the 11" on the top and the 27" under the blob on the end they would be 2kw / 3kw you can use either they will both heat the cylinder but the 27 will be 33% quicker (approx)

[keble]

Thanks so much for the quick replies. Really helpful. Am I correct in thinking tat the mid tank option would be the better choice, if there are in fact 2 boss'?

Unless there's any reason that this is a complex job, I'm thinking of attempting it. The 240v consumer unit has only 2 trips, which are both used, so it seems to me the simplest and tidiest option would be to replace that unit with a 4 way unit.

Paul, there was a previous thread on this topic, might be worth a look http://www.canalworld.net/forums/index.php?showtopic=53993&hl=

[paulmellors]

Paul, there was a previous thread on this topic, might be worth a look http://www.canalworld.net/forums/index.php?showtopic=53993&hl=

 

I've been reading and re-reading that over the past couple of days, very helpful.

 

I'm undecided about whether to power the immersion directly from the shoreline or from the consumer unit which is fed from the inverter. The inverter automatically detects shore power.

 

http://www.sterling-power.com/images/downloads/ProCombiQ_fitting_instructions.pdf

 

Feeding from the inverter will make cabling much cleaner and then we just need to make sure we only switch it on when on shore power.

 

The intention is to run the immersion off a fused, lit switch.

 

Does anything special need to be done with the earth or can this be wired from immersion to switch and then on to the consumer unit?

 

Again thanks for the ongoing help. It's giving me the confidence to take on the job myself.

 

Paul

[bottle]

Paul

 

With my inverter (Victron) it is possible to set it up so that the immersion heater will only run when a 240v supply is available, so it is impossible to run the immersion from the batteries.

 

Do not know if this is possible with the Stirling but someone on here may.

[paulmellors]

Ordered a sure cal 750w immersion to be on the safe side. The shore power at the boat club doesn't like big loads and a friend of ours has a 1kw and can't switch anything else on without tripping the power. Going to attempt the job sometime next week I think.

[bizzard]

Ordered a sure cal 750w immersion to be on the safe side. The shore power at the boat club doesn't like big loads and a friend of ours has a 1kw and can't switch anything else on without tripping the power. Going to attempt the job sometime next week I think.

The heater element for that calorifier will probably have a synthetic rubber ''O'' ring as gasket so no sealant needed, perhaps just a spot of silicone grease.

[smileypete]

I've been reading and re-reading that over the past couple of days, very helpful.

 

I'm undecided about whether to power the immersion directly from the shoreline or from the consumer unit which is fed from the inverter. The inverter automatically detects shore power.

 

http://www.sterling-power.com/images/downloads/ProCombiQ_fitting_instructions.pdf

 

Feeding from the inverter will make cabling much cleaner and then we just need to make sure we only switch it on when on shore power.

 

The intention is to run the immersion off a fused, lit switch.

 

Does anything special need to be done with the earth or can this be wired from immersion to switch and then on to the consumer unit?

 

Again thanks for the ongoing help. It's giving me the confidence to take on the job myself.

 

There should be a breaker between shoreline inlet and combi. If so an RCD fused spur could be wired downstream of the breaker and fitted with a 5A fuse to serve the 750W immersion.

 

That way the immersion still has RCD protection and appropriate fusing, and the shoreline inlet has protection from both immersion and combi drawing too much current. The immersion earth would be wired via back to the shoreline inlet via the fused spur as normal.

 

Here's an example of one but it's worth shopping around:

 

http://www.ebay.co.uk/itm/RCD-Fused-Spur-/330899730161

 

If cable with fine stranded conductors is used between fused spur and breaker, the stranded ends are best fitted with ferrules or crimp on pins/thin blades using a decent ratchet crimper, This is because normal domestic elec bits aren't designed for this sort of cable. Also any mains cable around the calorifer needs to be heat resisting cable.

 

If you haven't done this sort of thing before it'd be well worth getting a qualified spark or someone similarly competent to check it over before using. Even if a spark does the whole job, shouldn't cost more than around £100 if you source the bits first, any decent spark should be able to finish the cable ends properly as above.

 

ETA: Personally when fitting the immersion I'd use some Fernox LS-X jointing compound on the male thread and a very sparing amount of the female thread. The combination of metal to metal thread, plus water, heat and limescale could make the immersion quite hard to remove later, so filling the thread with a suitable JC could make it a lot easier. Have a look at UK Plumbers Forum for more info.

 

cheers, Pete.

~smpt~

Edited April 11, 2013 by smileypete

[paulmellors]

Thanks for the really informative post Pete.

 

I've been and had another look today. Some of the cabling is behind a panel (which I haven't had off yet).

 

We have s switch which can select shore power of inverter power and then a consumer unit with 2 a main breaker plus 2 trips 16a and 6a.

 

Nothing appears to be connected to the 2 trips and all 240v (either from the inverter or direct shore power) is just connected to the main trip.

 

If I went from the immersion to a 20a fused switch with light and then to the 6a breaker in the consumer unit, would that do the job?

 

I do intend to use 20a heat resistant cable for all the wiring.

 

Thanks everyone for the continued help. Wouldn't attempt this without the advice.

 

Paul

[keble]

Paul, there's a useful web site here:

http://www.smartgauge.co.uk/nb_ac_sys.html

which shows boat AC wiring schemes

[paulmellors]

Keble, that's a great help. Thank you

[paulmellors]

Looking at those diagrams, we seem to have a different variation.

 

We have a manual change over switch and one RCD. The RCD does break the 240v power irrespective of the whether we're on shore power or inverter power.

 

I need to get a couple of panels off to see what's happening from the shore power inlet to the manual switch.

[smileypete]

It does sound like there isn't any overcurrent protection between the combi and shoreline inlet. As the combi instructions call for it, the existing install isn't all that competent if it's missing.

 

Probably best to get another RCB/MCB 'garage consumer unit', fit after the shoreline inlet, and both it's RCD and 16A MCB can feed the immersion fused spur and combi or switch, as per the third diagram on the Smartgauge page.

 

From the questions you're asking it does sound like you're not too familiar with this sort of thing, and the existing install isn't all that good, so I'd still advise getting it done by a registered and qualified spark or someone equally knowledgeable and competent, or at the very least get it checked by them before it's used.

 

cheers, Pete.

~smpt~

[paulmellors]

Thanks for the advice Pete. Which I intend to take. I'm going to fit the immersion and do all the cabling, then get someone to finish it off.

 

Paul

[paulmellors]

Immersion is installed and working:-) Went for a surecal 750w heater. Bit of a big getting the blanking plug off but all done.

 

Thanks everyone for all the valuable advice.

 

Paul

[Grace and Favour]

OP:

 

Excellent stuff!

 

The warm water to shave in will seem the worthwhile luxury!!!!!