Fitting an Immersion Heater to a New Calorifier

[alan_fincher]

I have just bought a calorifier, and also an immersion heater, supplied unfitted.

I am well aware of warnings about possible leaks, or using too much force when fitting.

However no instructions were supplied, and the box for the immersion contains both a gasket and an O ring.  The O ring is smaller than the immersion tread, but could presumably be stretched over it.

I presume only one or the other should be used, but not both?

Googling the topic (immersion fitting in general, not specifically to a marine calorifier), yields lots of conflicting views expressed by people claiming to be professionals.  Some say add Boss White or PTFE as  well as whatever gasket or ring, whereas others suggest that's a bad idea.  Some also suggest use of tape will make it easier to remove if required a later date, others that it will make it harder?

So what are people's thoughts on the best way to do it?  Gasket ?? Ring??  And just those or do I apply anything to the threads as well?

What tips to avoid doing anything daft?

Edited October 29, 2017 by NB Lola
Smelling pisstakes

[bizzard]

8 minutes ago, alan_fincher said:

I have just bought a calorifier, and also an immersion heater, supplied unfitted.

I am well aware of warnings about possible leaks, or using too much force when fitting.

However no instructions were supplied, and the box for the immersion contains both a gasket and an O ring.  The O ring is smaller than the immersion tread, but could presumably be stretched over it.

I presume only one or the other should be used, but not both?

Googling the topic (immersion fitting in general, not specifically to a marine calorifier), yields lots of conflicting views expressed by people claiming to be professionals.  Some say add Boss White or PTFE as  well as whatever gasket or ring, whereas others suggest that's a bad idea.  Some also suggest use of tape will make it easier to remove if required a later date, others that it will make it harder?

So what are people's thoughts on the best way to do it?  Gasket ?? Ring??  And just those or do I apply anything to the threads as well?

What tips to avoid doing anything daft?

I fit quite a few here for fol, very limescaley district. I always use the rig if provided, but make sure the bushes surface on the calorifier is clean and true first. I just squirt a little silicone spray on the ring and tighten the element only a little over hand tight, easy to remove in the future. They never leak.  The gasket I usually use blue Hylomar on it and tighten it well. Much prefer the rings.

[ditchcrawler]

Nothing on the threads

We didn't use O rings in my day so that wasnt an option

[alan_fincher]

4 hours ago, bizzard said:

I fit quite a few here for fol, very limescaley district. I always use the rig if provided, but make sure the bushes surface on the calorifier is clean and true first. I just squirt a little silicone spray on the ring and tighten the element only a little over hand tight, easy to remove in the future. They never leak.  The gasket I usually use blue Hylomar on it and tighten it well. Much prefer the rings.

So to be clear your preference is the ring with nothing else, if one is supplied.  (You said "rig" but I assume that meant ring).

[bizzard]

38 minutes ago, alan_fincher said:

So to be clear your preference is the ring with nothing else, if one is supplied.  (You said "rig" but I assume that meant ring).

Yes, ring, no gasket, with just a touch of silicone spray or Vaselene on it. If the threaded bush surface is a touch uneven the ring will adapt to it much better too.

[adam1uk]

Having read that you were wondering how it went, I can now understand why you called it an ummersion!

[MtB]

My preference is to use the gasket. 

I fit hundreds of immersion heater elements each year professionally and I need a leak rate of absolutely zero, given the ball-ache of draining down again (unpaid!) to do it a second time.

A thin film of LSX or silicone on each of the two faces of the gasket - NONE on the threads - then nip up the element fairly tight makes a bulletproof watertight joint. Easy to break the joint later when the element needs replacing.

I experimented with the O rings when they first started being supplied and about one in 10 or 20 leaked, I found, grrrr....

[alan_fincher]

59 minutes ago, Mike the Boilerman said:

My preference is to use the gasket. 

I fit hundreds of immersion heater elements each year professionally and I need a leak rate of absolutely zero, given the ball-ache of draining down again (unpaid!) to do it a second time.

A thin film of LSX or silicone on each of the two faces of the gasket - NONE on the threads - then nip up the element fairly tight makes a bulletproof watertight joint. Easy to break the joint later when the element needs replacing.

I experimented with the O rings when they first started being supplied and about one in 10 or 20 leaked, I found, grrrr....

Until you posted this, I had become persuaded to use the O ring - now do I just toss a coin ?

Actually , though, I find nothing much generally gets past LS-X, so I'm not doubting that should be fine.

My main gripe with LS-X, not being a professional plumber, is that I always find that any opened tube I have, however well the cap is on, has gone off by the next time I need some.  Mental note - add LS-X to my BES order when I make it!

[NMEA]

It depends on the Boss, some are designed to use the O ring and have a tapered recess, some just have a flat surface for the gasket, so use the apropriate one, if it is designed for the gasket or O ring I use a little liquid PTFE more as a lubricant than a sealent to allow the gasket or O ring to spread, you shouldn't need anything on the threads of an Immersion, or any parallel threads, sealants are reserved for taper threads.

 

[Ex Brummie]

I only ever use the gasket, making sure the mating surfaces are flat and clean, and tightening just enough to stop any leaks.  Using the 'o' ring where you are screwing down offers a moving surface to the ring and often distorts it. I am also inclined to a turn or two of PTFE on the threads to facilitate demounting. Any form of sealer on the threads is a big no-no, as removal can become impossible.

[bizzard]

2 hours ago, Mike the Boilerman said:

My preference is to use the gasket. 

I fit hundreds of immersion heater elements each year professionally and I need a leak rate of absolutely zero, given the ball-ache of draining down again (unpaid!) to do it a second time.

A thin film of LSX or silicone on each of the two faces of the gasket - NONE on the threads - then nip up the element fairly tight makes a bulletproof watertight joint. Easy to break the joint later when the element needs replacing.

I experimented with the O rings when they first started being supplied and about one in 10 or 20 leaked, I found, grrrr....

Strange Mike, I respect your professionalism on the subject but Maybe the rings are of improved quality now, they would be something like silicone or Viton I expect. Were you using a lubricant,''Silicone, vasalene even a smear of brake fluid does the trick, like on an oil or fuel filter ring and not overtightening is crucial, especially if dry which might scuff or even snap the ring. The limescale is incredible here, one boat gets through elements every two years. I might suggest removing it once a year and de scaling and refitting it. One type of colorifier that I know of, may be Surecal, can't remember, a stainless steel one which does only use O rings.

[MtB]

4 minutes ago, Ex Brummie said:

Any form of sealer on the threads is a big no-no, as removal can become impossible.

 

Not true in my experience. In 40 years I have never failed to remove an immersion eater element, thread sealed or not.

Far more difficult when threads sealed, but certainly not impossible.

[MtB]

40 minutes ago, bizzard said:

 

It depends on the Boss, some are designed to use the O ring and have a tapered recess, some just have a flat surface for the gasket, so use the apropriate one,

 

Firstly, this quoting bug is getting worse. NMEA said this, not biz but I can’t correct it on this phone.

Secondly, I agree with NMEA, not all cylinder bosses have a nice champher machined at the top of the thread for the O ring. The O ring only seals by luck when the chamfered seat is missing. The gasket ALWAYS works. 

 

 

[bizzard]

7 minutes ago, Mike the Boilerman said:

Firstly, this quoting bug is getting worse. NMEA said this, not biz but I can’t correct it on this phone.

Secondly, I agree with NMEA, not all cylinder bosses have a nice champher machined at the top of the thread for the O ring. The O ring only seals by luck when the chamfered seat is missing. The gasket ALWAYS works. 

 

 

The stainless steel calorifier I mentioned have the tapered recess and the element fitting threads are of smaller diameter.

[ditchcrawler]

4 hours ago, Mike the Boilerman said:

My preference is to use the gasket. 

I fit hundreds of immersion heater elements each year professionally and I need a leak rate of absolutely zero, given the ball-ache of draining down again (unpaid!) to do it a second time.

A thin film of LSX or silicone on each of the two faces of the gasket - NONE on the threads - then nip up the element fairly tight makes a bulletproof watertight joint. Easy to break the joint later when the element needs replacing.

I experimented with the O rings when they first started being supplied and about one in 10 or 20 leaked, I found, grrrr....

As I said I fitted them pre O ring days, that was also pre LSX and other silicone substances so we smeared Boss White on both sides of the washer. Like Mike, we didn't want to go back. Working in Norfolk quite often the drain off didn't work due to hard water and I have siphoned many a cylinder with a hose stuffed down the hot water take off at the top.

[smileypete]

If using LS-X on a thread, I always put it on the male side of the thread so any excess squishes out to the non water side.

As for the cap annoyingly splitting off when the tube isn't used for ages, last night I found a random nut of what looks like M12 size is a passable fit on the tube. If anyone's interest, in the cause of advancing the human race I could splash out on a couple from Ebay, and report if they fit OK.

Edited October 29, 2017 by smileypete