Kentish RenoExtension

10 minutes ago, Jeremy Harris said:

Yes, with a pump that probably works just fine.  They were originally designed to just thermosyphon, as shown in the top diagram in the first post in the thread

Which is where rethinking was introduced. Huge differences in flow rates / turbulence inside the heater body. 
No decades of feedback in honesty, but two seasons heating a 300m2 build with the stats set to ~40oC without even a single sniff of bother is evidence enough to ‘argue’ the toss afaic.

Discussing this now with my electrician, over a pint or 3, and even he said it’s counter-intuitive to have the electrified head under the heater. I’ve seen enough immersions leaking through the seals to be cautious. Over cautious maybe, but I’ve deliberated and forged ahead from my own findings. 
So far, so good. 

Horizontal being discussed now......

 

Eventually.....

 

20 minutes ago, Nickfromwales said:

Which is where rethinking was introduced. Huge differences in flow rates / turbulence inside the heater body. 
No decades of feedback in honesty, but two seasons heating a 300m2 build with the stats set to ~40oC without even a single sniff of bother is evidence enough to ‘argue’ the toss afaic.

Discussing this now with my electrician, over a pint or 3, and even he said it’s counter-intuitive to have the electrified head under the heater. I’ve seen enough immersions leaking through the seals to be cautious. Over cautious maybe, but I’ve deliberated and forged ahead from my own findings. 
So far, so good. 

 

 

Frankly I'd not risk it, Nick.  Much, much easier to just plumb the things the right way up and have done with it.  They work fine like that, have been for decades without any issues.  It's no more risky for the electrical connections than an immersion fitted in the bottom of an insulated tank, anyway, probably less so, as any leaks are likely to bypass the electrics and run down the outside.  These things have been running the right way up all over NI without causing any problems with the electrics.

 

I just can't see any good reason for wanting to fit the thing upside down.

also worth noting that some (ours anyway) are a soldered-up sealed unit so not much chance of a leak. Oh and the fitting at the top is a standard one so the pipe won't slide on in...

9 hours ago, Jeremy Harris said:

 

 

Frankly I'd not risk it, Nick.  Much, much easier to just plumb the things the right way up and have done with it.  They work fine like that, have been for decades without any issues.  It's no more risky for the electrical connections than an immersion fitted in the bottom of an insulated tank, anyway, probably less so, as any leaks are likely to bypass the electrics and run down the outside.  These things have been running the right way up all over NI without causing any problems with the electrics.

 

I just can't see any good reason for wanting to fit the thing upside down.

Thanks Jeremy. The review board will reside over this today   

 

53 minutes ago, dpmiller said:

also worth noting that some (ours anyway) are a soldered-up sealed unit so not much chance of a leak. Oh and the fitting at the top is a standard one so the pipe won't slide on in...

Which supplier did you use? The one I used, not only were there no MI’s but the pipe does indeed slide all the way in and hit the element. Had to mark depth on the pipes to check they’re well clear as that would be disastrous for the element of a DIY warrior were to assume the element was a depth stop.  

15 minutes ago, Nickfromwales said:

Which supplier did you use? The one I used, not only were there no MI’s but the pipe does indeed slide all the way in and hit the element. Had to mark depth on the pipes to check they’re well clear as that would be disastrous for the element of a DIY warrior were to assume the element was a depth stop.  

 

https://www.ebay.co.uk/itm/Willis-Jacket-Complete-External-Immersion-Heater-Prewired-fully-assembled/202416631247?epid=1588852290&hash=item2f20f8adcf:g:wAgAAOSwfEJeHIev

 

even had MIs...

4 hours ago, dpmiller said:

https://www.ebay.co.uk/itm/Willis-Jacket-Complete-External-Immersion-Heater-Prewired-fully-assembled/202416631247?epid=1588852290&hash=item2f20f8adcf:g:wAgAAOSwfEJeHIev

 

even had MIs...

 

That's interesting since that's who I used to get my two heaters from as well. Perhaps they have more than one supplier (the elements themselves are from Tesla). One heater allowed me to 'drop' the pipe all the way down into the cylinder and with the other it hit the element (which i had assumed was the stop depth until I realised what was going on). Anyway, something to watch out for when fitting these - if your copper starts to glow nice and red.....

I have a feeling that either Willis didn't patent these things, or if they did, then it's now expired, as there seems to be several different manufacturers of them.  This probably explains why there are now several different types of essentially the same thing.  Once upon a time, the only manufacturer was Willis Heating, in Belfast (https://willis-heating.com/ ), but it seems that Willis have expanded into lots of related areas and don't seem to make the Willis heaters any more.

 

I first came across them nearly 30 years ago, as they were pretty commonplace in parts of SW Scotland, as well as NI (probably because it was often quicker to get stuff from Belfast than it was from Ayr or Dumfries, at least for those out where we used to live).  Not often fitted to new builds, but they seemed a pretty common fit  to houses that had things like back burners providing hot water.  The second house we bought when living there had a Baxi stove for hot water, with a Willis heater fitted alongside the cylinder.  Seemed to work very well, really handy for heating a bit of hot water very quickly if the stove was out. 

 

You can now get versions with a 1 kW immersion, and I have wondered whether one of those, fitted with a thermostat set for around 45°C and plumbed in to the hot feed under the basin might not make for a handy way to get instant hot water for hand washing.  They hold around 4 litres, more than enough for a quick hand wash.

 

Found this close up of the labels on a Willis (actually an Emerald Geyser version) that shows clearly the direction of flow and has a sensible warning that the whole thing has to be filled with water:

 

 

 

Surely mounted on its side would lead to a bigger air pocket inside??? I notice that one above must be fitted to a vented system only?

Yes, it's odd that that Emerald Geyser label sort-of implies that it should be mounted horizontally with the “side” connection downwards (assuming writing upwards). I'd think if you wanted to put one on its side, which seems sensible to me from the point of view of avoiding an air pocket but not having electrics under water, you'd put that connection on the top.

 

I also wonder why they say “vented system only”. Do they really mean max pressure 1.5 bar or something like that?

round these parts, upright mounting would be a given. But if on its side then side connection up yes.

 

 

16 hours ago, joe90 said:

Surely mounted on its side would lead to a bigger air pocket inside??? I notice that one above must be fitted to a vented system only?

 

14 hours ago, Ed Davies said:

Yes, it's odd that that Emerald Geyser label sort-of implies that it should be mounted horizontally with the “side” connection downwards (assuming writing upwards). I'd think if you wanted to put one on its side, which seems sensible to me from the point of view of avoiding an air pocket but not having electrics under water, you'd put that connection on the top.

 

I also wonder why they say “vented system only”. Do they really mean max pressure 1.5 bar or something like that?

 

 

If I turn the photo the right way up, so it shows it in the mounted position, does that help?

 

Isn't the idea to not get any air trapped because air is compressible.  This can store more energy than the equivalent volume of liquid.  It is why pressure vessels are tested with oil and not gas.  If they do fail, then only a little oil comes out.

We used to fit this sort of heaters to spa baths back in the 1980s.  I can't remember one failing.

1 hour ago, Jeremy Harris said:

If I turn the photo the right way up, so it shows it in the mounted position, does that help?

 

So why did they put the writing on sideways? If you wanted to give people a big hint as to which way round it has to go you'd orientate the writing to match unless, of course, you were a not-very-good industrial designer which is not entirely uncommon.

 

My only interest in this is that I'm thinking I might have a couple of these in the hot water system for my house (largely as PV diversion loads) which will be in the bottom corner of the A-frame on the south side of the house so will have quite a bit of volume available but not a lot of headroom. Mounting the things horizontally would help as you then don't need the extra height to be able to get the element out.

1 minute ago, Ed Davies said:

So why did they put the writing on sideways?

Agreed, also, most things that have to be orientated correctly have “this way up (arrow)”. Has anyone seen the MI,S for these things (not that most people read the instructions ?).

4 minutes ago, Ed Davies said:

 

So why did they put the writing on sideways? If you wanted to give people a big hint as to which way round it has to go you'd orientate the writing to match unless, of course, you were a not-very-good industrial designer which is not entirely uncommon.

 

My only interest in this is that I'm thinking I might have a couple of these in the hot water system for my house (largely as PV diversion loads) which will be in the bottom corner of the A-frame on the south side of the house so will have quite a bit of volume available but not a lot of headroom. Mounting the things horizontally would help as you then don't need the extra height to be able to get the element out.

 

 

My guess is that Emerald Geyser are just one of a handful of companies that have copied the original Willis heater.  These things were, to the best of my knowledge, only ever fitted in NI and the immediately surrounding area.  When I first came across them around 30 years ago, I'd not seen anything like it before, but one of the NI chaps at work assured me they were really common over the water, especially around the Belfast area.  Everyone there just know which way up they went, as they were in pretty common use.

 

These things were designed to be fitted alongside an existing hot water cylinder, within the confines of a hot press/airing cupboard.  The vertical mounting allowed this, as the thing can sit within the corner space pretty neatly, and just attach to the existing plumbing.

 

It's only in the last few years that people have been looking at using them for other purposes, and I have a faint suspicion that I may be partially to blame for this, as I remember mentioning them on Ebuild as a possible way to build a cheap and cheerful water heating system for UFH.  IIRC, this was around the time that @TerryE opted to fit them for just this purpose.  Before that, I'd not heard of them being used for running UFH before, although that doesn't mean that someone hadn't done it.

 

 

1 hour ago, joe90 said:

Agreed, also, most things that have to be orientated correctly have “this way up (arrow)”. Has anyone seen the MI,S for these things (not that most people read the instructions ?).

 

 

Yes, and the diagram (copied again below) I posted earlier is a direct copy of the original Willis instructions (Willis sold these as "Economisers" originally, as you can get a small volume of hot water quickly, without waiting for the whole tank to heat up).

 

Well our Willis has been heating the house for the last two years without any problems and it is mounted with the electrics at the top!

12 minutes ago, JanetE said:

Well our Willis has been heating the house for the last two years without any problems and it is mounted with the electrics at the top!

 

 

I don't doubt that they will work for a time mounted upside down, the issue is whether the inevitable air space that this causes will lead to longer term problems.  I'm not a fan of fitting things contrary to the designer's intentions, and when Willis designed these things they were very definitely intended to be mounted as shown in that diagram, and included warnings to ensure that the case must be completely filled with water (which cannot be the case if they are mounted upside down - sooner or later there is going to be air trapped in that big space above the side pipe).

34 minutes ago, Jeremy Harris said:

the issue is whether the inevitable air space that this causes will lead to longer term problems.

 

possibly not, immersion heater elements usually have 'cold zones' at each end (usually about 50mm apparently) 

 

http://www.tpfay.co.uk/information/glossary-descriptions-heating-elements/#ColdEndDef

 

http://www.tpfay.co.uk/our-products/straight-elements/#.Xiw24IV2vIU

37 minutes ago, A_L said:

 

possibly not, immersion heater elements usually have 'cold zones' at each end (usually about 50mm apparently) 

 

http://www.tpfay.co.uk/information/glossary-descriptions-heating-elements/#ColdEndDef

 

http://www.tpfay.co.uk/our-products/straight-elements/#.Xiw24IV2vIU

 

 

Yes, they do, but I bet heat will still be conducted up the cores to the air space (which may well be taller than 50mm anyway), and the manufacturer's instructions do state clearly that there should not be any air space within the thing.  That warm air space is also going to make corrosion around the brazed joins where the element and thermostat pocket are attached to the threaded part and around the exposed parts of the element themselves more likely, I suspect..

 

I just cannot see any logical reason for wanting to mount these things upside down, I'm afraid.  They have a long track record of working well for decades when mounted the right way up, yet now it seems some just want to mount them upside down because they think that the original manufacturer has got it wrong for all these years.  It's not even as if it's any harder to mount them the right way up, the work involved is exactly the same, and they don't take up any more room when mounted correctly.

I still think it is a safety issue.  Sometimes instructions seems counter intuitive, not following them is how nuclear power plants melt down.

Anyone willing to put an old paint pot half full of water on a stove, then compare it with a full paint pot on a stove.

See which lid flies the furthest.

Edited January 25, 2020 by SteamyTea

Ours didn't have the orientation diagram on it and IIRC minimal fitting instructions.  The arrows indicated water flow and there was no "this way up" orientation arrow.  

 

The gas accumulation issues are completely different for the standard in unvented cylinder installation where the Wills uses thermal circulation in a potable water environment where the water turnover might be ~1m³ / day, but in our usecase we have about 35 ltr of water in our UFH loops -- the same 35 ltr as 2½ years ago when it was first flushed and bled, so there is no further introduced gas to accumulate.  I can't see where this ~100 cm³ gas could come.

 

Whilst the inverted position might avoid a potential gas trap, IMO the device can't have been designed for this because of issues of electrical safety:  there is no appropriate IPS protection for the wiring contacts and thermal cut out so any seal failure on the element ring in the inverted position would result in electrical shorting.  TBH, I think that there are also pragmatic maintenance advantages in having the heater threaded end up, as the element is pretty much at the highest point in the circuit and being upright it could be replaced with minimal water loss if the element failed, thus simplifying refill, flushing, repressurising the system.

 

Incidentally our thermostat cutout is trimmed to ~50°C and I can't recall logging a peak temperature over ~35°C since the system was commissioned.

 

Notwithstanding this, the next time I do some maintenance to the system (possibly over the summer) I might add "cracking the coil" with a heater element key to see if it bleeds any gas to the todo list.

 

Edited January 26, 2020 by TerryE

16 minutes ago, TerryE said:

Whilst the inverted position might avoid a potential gas trap, IMO the device can't have been designed for this because of issues of electrical safety:  there is no appropriate IPS protection for the wiring contacts and thermal cut out so any seal failure on the element ring in the inverted position would result in electrical shorting.  TBH, I think that there are also pragmatic maintenance advantages in having the heater threaded end up, as the element is pretty much at the highest point in the circuit and being upright it could be replaced with minimal water loss if the element failed, thus simplifying refill, flushing, repressurising the system.

 

 

 

 

I can assure you that it was indeed designed to be fitted with the electrical connections at the bottom.  There must be many thousands of these in use in NI, all fitted the right way up.  The only cases I've seen of people fitting them upside down are on this forum and it's predecessor, so it seems to be something that has sprung up here.

 

We have a few members here from NI, and I'm sure they will confirm that they are always fitted the right way up over there, as shown in that diagram I posted above that is a copy of the original Willis instructions.

On a rainy morning with little to do I tried to find instructions fir fitting a Willis heater and all I could find was the diagram that @Jeremy Harris posted above. Also the Navitron forum talked about little information on the right way to fit them.