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installing a twin coil calorifier HELP!! please


jayeddi

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hi I am new to this site but  after some help please  I took on job fitting out a narrow boat for a customer and confused when it comes round to plumbing the calorifier  in 

I have been researching the cylinder and so far I have got that it  is a telford twin coil calorifier being feed from a webasto heater and also running off the engine I get the basics of how it works twin coils heating the tank up cold feed at bottom flow and return for central heating then I get confused to were the hot water is surpose to being comeing out please can someone help before I have an internal flood or melt down and maybe the best way to plumb this system up valves, expansion tanks, regulators etc I have uploaded the cylinder any  diagrams of how things works makes more sense to me then technical terms many thanks 

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In simple terms the hot supply to taps should be coming off the top, where it is currently shown with (I think) just a pressure relief valve plumbed on.

 

Whilst a PRV can be fitted anywhere that allows it to take water at excess pressure away from the tank, they are often fitted on the feed at the bottom, because in that way they can usually be used for draining the tank if ever required.

Edited by alan_fincher
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It's not hard to  Google and find lots of diagrams instructions about calorifier installation.

This is one of the first I found by Googling "boat calorifier installation", but there are dozens more.

 

This might not be the best, but the included diagram covers all the basics, I think....

 

http://heatmyboat.co.uk/installing-a-boat-calorifier/

 

Edited to add....

I would definitely avoid the arrangement you have pictured of "rubber" heater hose pushed on to lengths of plain 15mm copper pipe, and secured with worm drive clips.  This is something almost guaranteed to give trouble over time.  Use proper barbed connectors, and you have a much better chance of the hoses not eventually etaching themselves.

Edited by alan_fincher
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2 minutes ago, alan_fincher said:

It's not hard to  Google and find lots of diagrams instructions about calorifier installation.

This is one of the first I found by Googling "boat calorifier installation", but there are dozens more.

 

This might not be the best, but the included diagram covers all the basics, I think....

 

http://heatmyboat.co.uk/installing-a-boat-calorifier/

Why does OP’s calorifier have two connections low down? One female and one male. 

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ive seen this one before it shows the basics witch I get but just doest show much detail on the cylinder and with you sayin the hot comes out the top its get me even more confused wondering why the boat builders would fit it like that makes me wonder now 

 

would that mean the prv is being fitted to the cold feed of the tank and would it need a exspanstion vessal would it be good practice to fit one thanks

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Would be worth talking to Telford's with the details on the label. I've not come across them before as suppliers of marine calorifiers and their web site doesn't mention them being in that market. The may be able to give details of the ports for you. In particular you need to check that it is designed for a working pressure around 3 to 3.5 bar. The picture in your post most resembles some of the vented cylinders on their web site, which are usually designed for lower working pressure and may not cope with 3.5 bar. It could be a tank designed for a combination of central heating boiler and solar thermal hot water, hence the twin heating coils. The two ports low down is weird. Would expect only one. Also the port 3/4 the way up.

 

Jen

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Just now, jayeddi said:

would that mean the prv is being fitted to the cold feed of the tank and would it need a exspanstion vessal would it be good practice to fit one thanks

Ideally you will have an NRV (non return valve) in the feed, to stop heated water being pushed back into your cold water supply.

If you do, then there should be an EV (expansion vessel) after that point, otherwise each time water is heated and expands, it will be ejected via the PRV (pressure relief valve).  The link I have posted shows the ideal arrangement, in my view.

2 minutes ago, WotEver said:

Drain maybe. He has a PRV point on the left above the sticker. 

Yes missed that....
 

Cold feed and drain at bottom.

 

PRV near sticker.

 

Hot out at the top.

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6 minutes ago, alan_fincher said:

the hoses don't look to clever to be honest and didt even cross my mind when it heats up bound to come off at some point I think the hole on the left next to the sticker is maybe flow and return for central heating ive also asked telford them selfs and they cant seem to find this tank any more so was wondering if it was just a odd one laying about before being fitted into this boat 

 

 

this is what telford have sent back on to the only one they could find 

pic.jpg

5 minutes ago, Jen-in-Wellies said:

Would be worth talking to Telford's with the details on the label. I've not come across them before as suppliers of marine calorifiers and their web site doesn't mention them being in that market. The may be able to give details of the ports for you. In particular you need to check that it is designed for a working pressure around 3 to 3.5 bar. The picture in your post most resembles some of the vented cylinders on their web site, which are usually designed for lower working pressure and may not cope with 3.5 bar. It could be a tank designed for a combination of central heating boiler and solar thermal hot water, hence the twin heating coils. The two ports low down is weird. Would expect only one. Also the port 3/4 the way up.

 

Jen

this is what telford have sent back if that makes any sense

pic.jpg

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5 minutes ago, Jen-in-Wellies said:

Would be worth talking to Telford's with the details on the label. I've not come across them before as suppliers of marine calorifiers and their web site doesn't mention them being in that market. The may be able to give details of the ports for you. In particular you need to check that it is designed for a working pressure around 3 to 3.5 bar. The picture in your post most resembles some of the vented cylinders on their web site, which are usually designed for lower working pressure and may not cope with 3.5 bar. It could be a tank designed for a combination of central heating boiler and solar thermal hot water, hence the twin heating coils. The two ports low down is weird. Would expect only one. Also the port 3/4 the way up.

 

Jen

Good spot.

I think it probably says 1.5 bar on the label - but it is hard to tell.

 

If it does, then as Jen says, this is not a boat calorifier, but a domestic hot water cylinder.

It will almost certainly fail over time if it is subjected to the pressures associated with a boats pumped system, which are typically double what it looks like it says it is rated for.

 

If that label does say 1.5 psi, save a load of future grief by scrapping it, and buying an actual calorifier.
 

(This isn't scaremongering - the previous owner of my boat had fitted domestic hot water cylinders, and, unsurprisingly, they were found to be leaking, and I had to write them off).

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16 minutes ago, jayeddi said:

 

 

this is what telford have sent back on to the only one they could find 

pic.jpg

this is what telford have sent back if that makes any sense

pic.jpg

The cold water feed maximum pressure of 1.5 bar is low for a marine calorifier, which again suggests it is an vented domestic style cylinder. The water pumps typical to give decent flow rates on a narrowboat will be higher pressure than this. See @alan_fincher's post above. The 3 bar safety valve is a more typical value though and it is described as a marine calorifer. 1mm copper thickness seems too low to me. I'm with Alan. Replace it with a known marine calorifier. It is less likely to cause grief later.

 

Jen

Edited by Jen-in-Wellies
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Far from ideal but there is always the option of setting the domestic water pump cut out pressure to 1 bar (15psi). That may give enough flow for the customer, it did on my boat but I use a low pressure to minimise the possibility of leaks and hoses blowing off.

 

If the OP decides to do this I would suggest an expansion vessel is absolutely vital.

 

.

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10 hours ago, alan_fincher said:

So it is max 1.5 Bar.

I don't think you would get away with that for very  long - you need the proper marine item.

 

Just to point out that the title on the Telford tech drawing is ‘......twin coil marine’

 

The drawing also states a 3bar prv with a 1.5bar max supply pressure, which for me is a bit low as my whale pump is 2 bar, and I like having 2 bar.  So if the op keeps this tank he/she needs to confirm pump supply pressure is in spec.  If pump pressure is too high and/or an expansion vessel is not fitted to the system I suspect it will not be long before the calorifier cracks.

 

So whilst it does appear to be a marine calorifier it is not one I would have chosen.

Edited by Chewbacka
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2 minutes ago, Chewbacka said:

Just to point out that the title on the Telford tech drawing is ‘......twin coil marine’

Good spot, although it also says max 1.5 bar on the cold water inlet which seems incompatible with a typical narrowboat installation. This whole thing has "bodge" written all over it.

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Stone Boat Building supplied 1.5 bar copper marine calorifiers for many years and they were OK providing the pump was a low pressure one and the PRV was also a low pressure release.

 

It is easier to use a steel calorifier designed for a 3 bar PRV and pump set up but there is no reason why the present calorifier needs changing providing all the other bits are compatible. 

 

Whale supply 1 bar pumps and I find that pressure is sufficient for most boats if the plumbing is well done. Higher pressures = bigger floods when something fails.

Edited by Boater Sam
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1 hour ago, Tony Brooks said:

Far from ideal but there is always the option of setting the domestic water pump cut out pressure to 1 bar (15psi). That may give enough flow for the customer, it did on my boat but I use a low pressure to minimise the possibility of leaks and hoses blowing off.

 

If the OP decides to do this I would suggest an expansion vessel is absolutely vital.

 

.

It is an option. Depending on the layout of the boat and the pipe diameters and run lengths, the flow rate to a shower might be frustratingly low as a result. I can see an owner in the future deciding to fit a higher pressure water pump to get round this and the cauliflower failing shortly after. If the OP does decide to go this way, then using 22mm, rather than 15mm pipe for as much of the runs from the water tank to the shower as possible would help to minimise pressure drop.

 

Jen

Edited by Jen-in-Wellies
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2 hours ago, Chewbacka said:

The drawing also states a 3bar prv with a 1.5bar max supply pressure

What on earth though is achieved by putting a 3bar PRV on a cylinder rated to only have a maximum 1.5 bar supply pressure?

 

It hardly inspires confidence.

 

The OP is not giving the impression they know enough about boat plumbing to install a deliberately low pressure pump, and then try and compensate for poor delivery rates by large bore pipework, (or any other suggestion just made by others).

 

All I can say is I have had a boat that came with a 1.5 bar rated cylinder and water pissing out of it.

I know what I'd do in this case, and it wouldn't involve trying to use this cylinder.

 

At the end of the day, though, I guess it is up to the OP if they want to risk it.

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13 hours ago, David Mack said:

Am I alone in thinking that if the OP know as little about marine plumbing

as his posts and photos suggest, he should not be taking money from a paying customer for this sort of work?

well to be polite I no plenty about plumbing but unsure of weather to plumb this system in hence me getting proper advise depending on what I think ill eaither take the course weather to do it my self or get a plumber whos done this before but thanks for your concern

1 hour ago, alan_fincher said:

What on earth though is achieved by putting a 3bar PRV on a cylinder rated to only have a maximum 1.5 bar supply pressure?

 

It hardly inspires confidence.

 

The OP is not giving the impression they know enough about boat plumbing to install a deliberately low pressure pump, and then try and compensate for poor delivery rates by large bore pipework, (or any other suggestion just made by others).

 

All I can say is I have had a boat that came with a 1.5 bar rated cylinder and water pissing out of it.

I know what I'd do in this case, and it wouldn't involve trying to use this cylinder.

 

At the end of the day, though, I guess it is up to the OP if they want to risk it.

the diagram of the cylinder is what telford can only match it up to its not the actual one they have shown only said its very simaler 

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14 hours ago, alan_fincher said:

Good spot.

I think it probably says 1.5 bar on the label - but it is hard to tell.

 

If it does, then as Jen says, this is not a boat calorifier, but a domestic hot water cylinder.

It will almost certainly fail over time if it is subjected to the pressures associated with a boats pumped system, which are typically double what it looks like it says it is rated for.

 

If that label does say 1.5 psi, save a load of future grief by scrapping it, and buying an actual calorifier.
 

(This isn't scaremongering - the previous owner of my boat had fitted domestic hot water cylinders, and, unsurprisingly, they were found to be leaking, and I had to write them off).

I have a feeling you might be right there as I cannont find it anywere as marine one but only as a domestic and to be honest the label looks like its just been stuck on with no care im in two minds weather just to plumb all the hot cold and rads up as they should be then leave it before it gets connteced to the tank and seek professianl advise whats yours thoughts 

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