Calorifier

[ChrisPy]

hey, we should not degrade the noble profession of licensed heating engineers.

 

 

 

.............. mind you some of them actually do have a sense of humour. when we fixed up our kitchen this summer the plumper had "a little 'otter" scrawled on the side of his white van. He loved being called Tarka.

 

 

 

signed by an unlicensed pipe engineeer.

currently fitting 403km of class 900 48" welded steel around a few mountains.

PS we bury our leaks

I won't bore you with the list of engineering and professional qualifications, but none of them includes the word license or even licence, 'xept for that credit card sized plastic thingy the police are always looking at.

 

funny story about PRVs.

we commissioned an lpg pipeline into a storage and bottling plant, and we were making an inspection during the warranty period at the height of an Arabian summer.

at the pig receiving station connected to 20million litres of lpg storage we found all the valves isolating the PRVs (which we had left locked open with padlocks and seals) had been disturbed and were all closed.

when we enquired we were told by the licensed operator that the valves had been blowing off regularly in the heat, and he thought it was dangerous to have uncontrolled releases of lpg near the plant.

we made a hasty exit.

[Guest TerryL]

hey, we should not degrade the noble profession of licensed heating engineers.

 

 

 

.............. mind you some of them actually do have a sense of humour. when we fixed up our kitchen this summer the plumper had "a little 'otter" scrawled on the side of his white van. He loved being called Tarka.

 

 

 

signed by an unlicensed pipe engineeer.

currently fitting 403km of class 900 48" welded steel around a few mountains.

PS we bury our leaks

I won't bore you with the list of engineering and professional qualifications, but none of them includes the word license or even licence, 'xept for that credit card sized plastic thingy the police are always looking at.

 

funny story about PRVs.

we commissioned an lpg pipeline into a storage and bottling plant, and we were making an inspection during the warranty period at the height of an Arabian summer.

at the pig receiving station connected to 20million litres of lpg storage we found all the valves isolating the PRVs (which we had left locked open with padlocks and seals) had been disturbed and were all closed.

when we enquired we were told by the licensed operator that the valves had been blowing off regularly in the heat, and he thought it was dangerous to have uncontrolled releases of lpg near the plant.

we made a hasty exit.

It's just as well it's not me claiming to be a licenced/licensed heating engineer then! Some people just can't read!

 

I suppose this story makes you think whether you should actually have isolating valves before a PRV, or have other means of containing the expansion or have sun protection or even having LPG in the first place! Did no one realise 20million litres of LPG would expand quite a bit in a hot country?

[ChrisPy]

I suppose this story makes you think whether you should actually have isolating valves before a PRV ................

how would you temporarily remove them for 'popping' in a calibration laboratory every 6 months (to maintain safety certification of the plant) if you don't have isolation valves? For that reason every section has redundancy so you can remove one while leaving another in place.

 

watching for occasional fountains of lpg turning to mist in the midday heat is quite entertaining, a bit like waiting for a geyser in Yellowstone to blow

 

 

It's just as well it's not me claiming to be a licenced/licensed heating engineer then! Some people just can't read!

QUOTE : I'm a heating engineer and I have a license to install these things ....................

 

so by your own admission you are a heating engineer and you have a license (sic) but you are not claiming to be a licensed heating engineer.

 

 

.................................

[Guest TerryL]

how would you temporarily remove them for 'popping' in a calibration laboratory every 6 months (to maintain safety certification of the plant) if you don't have isolation valves? For that reason every section has redundancy so you can remove one while leaving another in place.

 

watching for occasional fountains of lpg turning to mist in the midday heat is quite entertaining, a bit like waiting for a geyser in Yellowstone to blow

 

 

 

QUOTE : I'm a heating engineer and I have a license to install these things ....................

 

so by your own admission you are a heating engineer and you have a license (sic) but you are not claiming to be a licensed heating engineer.

 

 

.................................

I appreciate they would need checking but it's hardly safe if they can be turned off as you described.

 

...licence to install these things refers to unvented hot water cylinders which is the subject of this thread.

[mikevye]

Only one person genuinely interested then? Hardly worth the effort if the only one has a closed mind and thinks hot water stratification is waffle! Learn about it and I won't need to repeat myself. http://wiki.diyfaq.org.uk/index.php?title=...#Stratification

 

BTW we might as well accept the ineviable and use the U.S spellings and terminology for things like licence/license much the same as someone claiming to be a math and physics major when they mean they've got two "O" levels!

 

I have now read the article about stratification and can see why you made your comments re cold water in calorifier. But again when you were critical about the fitting of a NRV you have made an assumption as to the installation of the HW system in my boat and possibly others. You have not identified that I have a horizontal cylinder with three direct heat sources and an indirect source from the ambient temperature of the engine room which even in winter is a factor to be considered. Then there is the movement of the boat further evening out the temperature in the vessel. In a tall household cylinder with the heating element at the top I can go along with your comments but in a marine environment which is the discussion topic, NO WAY!

[chris w]

BTW we might as well accept the ineviable and use the U.S spellings and terminology for things like licence/license.........

....................or get an education and learn to spell - you will give heating engineers a bad name. And BTW, having a license (sic) doesn't make you an "engineer".

 

I realise now you are probably quite balanced, having a chip on both shoulders about your background and "education". The politics of envy..

[blackrose]

I am afraid that you are espousing nonsense again. I have an expenasion vessel on my calorifier on the hot water outlet and it is set at about 35psi (ie: between the water pump's cut-OUT pressure and the PRV setting). This is exactly what the supplier of the expansion vessel stated should be done and is entirely logical if you follow the sequence of events. If the expansion vessel pressure were lower than the pump's cut-OUT pressure then there would be no expansion space available. It would get "expanded into" everytime the pump came on.

 

"Surecal", the manufacturer from whom I obtained my expansion vessel (and one of the largerst manufacturers of calorifiers and expansion vessels etc) agree with my thinking if you care to check out their website.

 

Jabsco (Cleghorn Waring), also recommend fitting an expansion vessel (such as an accumulator tank normally used after the water pump), to the hot water side of the system, either on the cold water inlet side of the calorifier after the non-return valve (if one is present), or on the hot water outlet side of the calorifier. They sent me a nice diagram with my new waterpump, but unfortunately it's not on their website.

Edited November 6, 2008 by blackrose

[Batavia]

I appreciate they would need checking but it's hardly safe if they can be turned off as you described.

 

For most process plants and in many storage situations, you don't have the luxury of being able to shutdown the plant, drain down the system, etc. in order to remove a PRV for testing. Hence duplicated valves are frequently used, with procedures and/or mechanical interlocks being used to ensure that one PRV is always connected to the process.

 

There are alternatives to removing the valve, such as TREVI testing, but frequently there will be many interlocks associated with a PRV lifting and to do the testing you have to over-ride these - which in turn has a well-established history of causing yet more problems.

 

If a plant operator deliberatly over-rides safety devices - leave the area hastily....

 

Chris G

 

(Totally "unlicenced" engineer, but been doing it professionally for a while)

[chris w]

(Totally "unlicenced" engineer, but been doing it professionally for a while)

 

 

The thought police will be after you Chris. "unlicenced" (sic) is a past participle and therefore should be written with an "s" (ie: "unlicensed"). No offence to you, I just didn't want to confuse TerryL... he's easily confused.

 

Chris

Edited November 6, 2008 by chris w

[Gibbo]

Not my field at all but I'm gonna throw my thruppence in anyway coz it's wot a boat heating man told me who seems to do a good job.

 

On a boat with a horizontal calorifier (the norm), a NRV (the norm), NO expansion tank (the norm) and a PRV (the norm) then every time the water is heated the PRV will trickle water over the side. This will happen almost every time it is heated. If the PRV sticks there is a good chance the calorifier will burst. Apparently PRVs stick a lot so why do we not see loads of burst calorifiers?

 

The reason is that the hot water take off from the (horizontal) calorifier and the PRV are not usually right at the top. They're usually a few inches below, so when the calorifier is filled it leaves an airgap in the top which acts as an expansion vessel.

 

Just what I was told and it seems to make sense.

 

Gibbo

[blackrose]

Not my field at all but I'm gonna throw my thruppence in anyway coz it's wot a boat heating man told me who seems to do a good job.

 

On a boat with a horizontal calorifier (the norm), a NRV (the norm), NO expansion tank (the norm) and a PRV (the norm) then every time the water is heated the PRV will trickle water over the side. This will happen almost every time it is heated. If the PRV sticks there is a good chance the calorifier will burst. Apparently PRVs stick a lot so why do we not see loads of burst calorifiers?

 

The reason is that the hot water take off from the (horizontal) calorifier and the PRV are not usually right at the top. They're usually a few inches below, so when the calorifier is filled it leaves an airgap in the top which acts as an expansion vessel.

 

Just what I was told and it seems to make sense.

 

Gibbo

 

I suspect there's a bit of expansion in the plastic pipes too, but personally should the PRV get stuck I wouldn't want to rely on the flexibility of the pipes or a bit of air in the top of the calorifier from preventing it exploding .

[Gibbo]

I suspect there's a bit of expansion in the plastic pipes too, but personally should the PRV get stuck I wouldn't want to rely on the flexibility of the pipes or a bit of air in the top of the calorifier from preventing it exploding .

 

I agree completely. I have no expansion vessel on my boat. But I think I am now going to fit one!

 

Gibbo

[Guest TerryL]

The thought police will be after you Chris. "unlicenced" (sic) is a past participle and therefore should be written with an "s" (ie: "unlicensed"). No offence to you, I just didn't want to confuse TerryL... he's easily confused.

 

Chris

Yes you do confuse me, I'm still trying to work out how you get an RCD to work without an earth connection on the supply, according to you it just works with an imbalance on a loop circuit!!! It doesn't work but it's spelt proper!

[chris w]

Yes you do confuse me, I'm still trying to work out how you get an RCD to work without an earth connection on the supply, according to you it just works with an imbalance on a loop circuit!!! It doesn't work but it's spelt proper!

You're a f****** liar cos I've never said that. One MUST have an earth to ensure an RCD operates. Don't worry the registered letter will be arriving at your place within a few more days.

[chris w]

You still have never explained why you recommend people should disconnect the alternator from their battery while the alternator is running. !!!!!!Totally nuts. Neither Gibbo nor I would agree with that. It's one of the warnings he gives on his web site.

[Guest TerryL]

You're a f****** liar cos I've never said that. One MUST have an earth to ensure an RCD operates. Don't worry the registered letter will be arriving at your place within a few more days.

 

Oh dear, temper, temper Chris, f****** liar am I? You know what that means don't you? I think you'd better stop this before it gets out of hand, say sorry!

 

(chris w @ Nov 11 2006, 12:54 PM) <{POST_SNAPBACK}>

 

Actually, the beauty of an RCD is that it detects current imbalance between the Live and Neutral lines, so will work if any imbalance arises even if the diverted current is not to "earth"

 

 

 

You still have never explained why you recommend people should disconnect the alternator from their battery while the alternator is running. !!!!!!Totally nuts. Neither Gibbo nor I would agree with that. It's one of the warnings he gives on his web site.

No you are wrong again, I said you can disconnect the battery, not the alternator, a big difference that Sir Nibble agrees with.

[chris w]

No you are wrong again, I said you can disconnect the battery, not the alternator.......

If you disconnect the battery (ie: remove the B+ cable) you will almost certainly destroy the rectifier diodes. So what do YOU mean by "not disconnecting the alternator" but it's OK to "disconnect the battery"????????????????????

 

Taking off the B+ cable at either end (alternator or battery end) whilst the alternator is running can destroy the diodes. You however say this is OK.

 

The only other leads one could detach are the D+ lead or the field wire (if fitted externally). Disconnecting either of these will not do any harm to the alternator.

 

So explain the difference in what you mean. You won't of course, you never do.

Edited November 6, 2008 by chris w

[chris w]

Oh dear, temper, temper Chris, f****** liar am I? You know what that means don't you? I think you'd better stop this before it gets out of hand, say sorry!

 

QUOTE (nick the boats @ Oct 20 2008, 09:41 AM) QUESTION

 

As this is a long topic and I am a slow reader, this may have already been covered, but here goes.

My shore power only connects to my battery charger, charger to batteries, batteries to inverter (own cables) to 240 sockets via trip fuse.

Also from batteries to 12 volt fuse panal and buzz bar (own cables).

The battery negatives are common and are connected to the engine.

My question is, is this acceptable or should there be anything else?

thanks

Nick

 

ANSWER

 

Yes Nick.

 

1. You need to earth the incoming mains to the hull.

 

2. Install an RCD (Residual Current Device) on the mains circuit before the "trip fuse" (MCB= miniature circuit breaker).

 

3. You also need to double check that the engine is actually connected to the hull. Don't assume it is - measure it. It is sitting on rubber mounts. If it isn't then you need to connect the engine to the hull.

 

4. You need to connect the earth and neutral of your inverter together and ensure the inverter case is earthed to the hull. Otherwise the RCD will not blow if there is an inverter live fault. Some inverters come supplied already like this (eg: Sterling)

 

Chris

[mikevye]

I agree completely. I have no expansion vessel on my boat. But I think I am now going to fit one!

 

Gibbo

 

Our calorifier (horizontal) failed after only 15 months and I'm now aware of a boat built just afterwards that had a similar problem, similar systems in both boats. I've fitted an expansion tank if he doesn't in just over a years time we should have a reasonable argument for and against the fitting of a tank! After removing the lagging from mine to see if it would repair I found out that it had actually cracked so in my mind the fitting of an expansion vessel is essential to prevent a similar occurence. Having established that it was beyond repair I weighed it in and got £30, bonus against the cost of a bare shell which cost half the price of a retail unit.

 

 

 

 

PS chris w and terryl please don't change I log on every day for an update on your latest arguments

[RLWP]

Our calorifier (horizontal) failed after only 15 months and I'm now aware of a boat built just afterwards that had a similar problem, similar systems in both boats. I've fitted an expansion tank if he doesn't in just over a years time we should have a reasonable argument for and against the fitting of a tank! After removing the lagging from mine to see if it would repair I found out that it had actually cracked so in my mind the fitting of an expansion vessel is essential to prevent a similar occurence. Having established that it was beyond repair I weighed it in and got £30, bonus against the cost of a bare shell which cost half the price of a retail unit.

 

To help you build up your picture, we do not have any expansion vessels or NRVs. We do have a horizontal cylinder which, as Gibbo pointed out, almost certainly contains some air. There is about 50-60ft of plastic pipe to the calorifier and 6-70ft after it. We are five years into our ownership and the cylinder wasn't new when we bought the boat. No split calorifier yet.

 

Richard

[mikevye]

To help you build up your picture, we do not have any expansion vessels or NRVs. We do have a horizontal cylinder which, as Gibbo pointed out, almost certainly contains some air. There is about 50-60ft of plastic pipe to the calorifier and 6-70ft after it. We are five years into our ownership and the cylinder wasn't new when we bought the boat. No split calorifier yet.

 

Richard

 

I can go along with Gibbos comment but if you've fitted Hep2o piping I can only accept a nominal expansion in a linear direction but virtual nil around the circumference.

[Phoenix_V]

Not my field at all but I'm gonna throw my thruppence in anyway coz it's wot a boat heating man told me who seems to do a good job.

 

On a boat with a horizontal calorifier (the norm), a NRV (the norm), NO expansion tank (the norm) and a PRV (the norm) then every time the water is heated the PRV will trickle water over the side. This will happen almost every time it is heated. If the PRV sticks there is a good chance the calorifier will burst. Apparently PRVs stick a lot so why do we not see loads of burst calorifiers?

 

The reason is that the hot water take off from the (horizontal) calorifier and the PRV are not usually right at the top. They're usually a few inches below, so when the calorifier is filled it leaves an airgap in the top which acts as an expansion vessel.

 

Just what I was told and it seems to make sense.

 

Gibbo

 

What happens with vertical cylinders/

[Smelly]

Might I just say YYYAAAAAAAAAAAAAAAYY Gibbo's lurkin' At last a voice of educated reason! Welcome back matey in whetever limited way you might see fit.

 

We've got two vertical calorifiers, linked in series with a fancy valve/NRV arrangement so we can choose between either depending on whether we've a fire lit. There's not an expansion vessel anywhere, however the bath, where the PRV's drain, is a few mm deep on a cold night. I open the PRV's once very couple of months to make sure and blow any scale off.

 

I will fit an expansion vessel, or two, one day, in the meantine the PRV's, both of em, stop everything ballooning like Troll's.

 

When I fitted the dump load for the solar connection earlier in the year I was pleased to note that there was not a drop of air on the top of the cal's... Being a biologist by training I reckon any opportunity for aerobic respiration is a bad thing (says he who regularly gets hot hot water WAY above 60 degC).

 

What I'm getting at, as Richard has said above... if you don't mind losing a bit of water, then a PRV is as good a control measure as an expansion vessel, and is always (or should be) the last measure. I understand a want for them, especially in a resource strained world, however there's a couple of decades past where they weren't the norm so why the fuss now?

 

I'd argue a PRV is essential though.

[Guest TerryL]

What happens with vertical cylinders/

Probably means you're sinking stern first!

[ChrisPy]

PS chris w and terryl please don't change I log on every day for an update on your latest arguments

they are one and the same - alter egos ................