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Hello everyone Alto this is my 1st post on here I’ve been reading the forum for some time. I’m at the plumbing stage of fitting out a Dutch barge. I was wondering if anyone could point out anything I’ve missed or need to think about with my central heating plans. I’ve attached a basic diagram of what I hope to do. 
 

I’ll be using a Webasto thermo top C 

55L calorifier 

22mm speedfit for feed and return ring

15mm outlets to the rads and calorifier 

double pipe header tank

 

isolation valves are black “no entry” symbols

oneway valves are light blue direction symbols

 

Thanks 

 

 

3CBF462C-2703-4AD0-871A-2040A21D958D.jpeg

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This is taken directly from the Webasto installation manual 

 

”Balance the system
Balance the radiators with the lockshields and remember to fit a lock shield / balancing valve to the Calorifier coil outlet pipe. Also, do not pipe the Calorifier in series with the spine

 

thanks for pointing that out tho as I’ve just noticed it says to put the balancing valve on the outlet  not the inlet as per my diagram 

Edited by Greenhorn
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1 hour ago, WotEver said:

Wouldn’t it be more normal to have calorifier in series with the rads to prevent the system taking a short cut through it?

Normal yes, but problematic. My boat has a cauliflower and a couple of rads heated by a gravity circulated stove back boiler all in series through big bore copper pipes, caloriifier before the rads. If I come to the boat and the cauliflower is stone cold it sucks all the heat from the stove for several hours after lighting it till the water is up to temperature. Only then does the boat itself start to warm up. With a pumped system and parallel balanced feeds to the cauliflower and radiators the boat would heat up more quickly, with a corresponding longer time to get hot water.

Jen

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You don't need the one way valves. They will just hinder the flow from the Webasto pump.

As drawn, you have no way to heat  your hot water without having the radiators on, unless you turn them off individually (and you don't have a valave on the far radiator). Better to have an additional valve in the main hot pipe just after the T to the calorifier, so you can turn off the whole of the radiator circuit. Equally, having this valve open and the calorifier valve closed will give a quicker heating up of the cabin space if you arrive at the boat in cold weather.

The diagrammatic presentation doesn't show the pipe gradients, but you should arange the pipework so that there is a continuous rise in the main pipework towards the radiators and the main header tank (with bleed valves fitted to the radiators). Otherwise you will have difficulty getting air out of the system when filling.

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44 minutes ago, David Mack said:

You don't need the one way valves. They will just hinder the flow from the Webasto pump.

As drawn, you have no way to heat  your hot water without having the radiators on, unless you turn them off individually (and you don't have a valave on the far radiator). Better to have an additional valve in the main hot pipe just after the T to the calorifier, so you can turn off the whole of the radiator circuit. Equally, having this valve open and the calorifier valve closed will give a quicker heating up of the cabin space if you arrive at the boat in cold weather.

The diagrammatic presentation doesn't show the pipe gradients, but you should arange the pipework so that there is a continuous rise in the main pipework towards the radiators and the main header tank (with bleed valves fitted to the radiators). Otherwise you will have difficulty getting air out of the system when filling.

Pipe gradients are not needed. As long as the header tank is as high as possible it will bleed easily at the farthest radiator and self bleed through the 2 pipe header tank.

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Calculate the total expansion of your speedfit when it heats up. The expansion on mine turned out to be 6" and wiggled all over the place so I re-did it all in copper.

 

Calculate the total heat output of your radiators etc and ensure that it meets Webasto's recommendations.

 

I installed mine without any check valves or whatever they're called whatsoever and I haven't found a need for them on my double-pipe system.  The pipes go straight in and out of each radiator.  I don't have a cauliflower.  I have a 2 pipe reservoir with bypass as in the Webasto manual "best option" and I don't have any problems with bleeding though I can't see any way around loosening the boiler top hose but that only required doing once so far and was easy.

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1 hour ago, David Mack said:

You don't need the one way valves. They will just hinder the flow from the Webasto pump.

As drawn, you have no way to heat  your hot water without having the radiators on, unless you turn them off individually (and you don't have a valave on the far radiator). Better to have an additional valve in the main hot pipe just after the T to the calorifier, so you can turn off the whole of the radiator circuit. Equally, having this valve open and the calorifier valve closed will give a quicker heating up of the cabin space if you arrive at the boat in cold weather.

The diagrammatic presentation doesn't show the pipe gradients, but you should arange the pipework so that there is a continuous rise in the main pipework towards the radiators and the main header tank (with bleed valves fitted to the radiators). Otherwise you will have difficulty getting air out of the system when filling.

My only reason for not being able to turn off certain radiators is for correctly loading the wabasto. I plan to keep the towel rail and top rad open to deal with this. The bottom one can be closed when not needed (in summer)

Edited by Greenhorn
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34 minutes ago, system 4-50 said:

Calculate the total expansion of your speedfit when it heats up. The expansion on mine turned out to be 6" and wiggled all over the place so I re-did it all in copper.

 

Calculate the total heat output of your radiators etc and ensure that it meets Webasto's recommendations.

 

I installed mine without any check valves or whatever they're called whatsoever and I haven't found a need for them on my double-pipe system.  The pipes go straight in and out of each radiator.  I don't have a cauliflower.  I have a 2 pipe reservoir with bypass as in the Webasto manual "best option" and I don't have any problems with bleeding though I can't see any way around loosening the boiler top hose but that only required doing once so far and was easy.

Maybe a silly question but how do I workout expansion? 

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53 minutes ago, system 4-50 said:

Calculate the total expansion of your speedfit when it heats up. The expansion on mine turned out to be 6" and wiggled all over the place so I re-did it all in copper.

 

Calculate the total heat output of your radiators etc and ensure that it meets Webasto's recommendations.

 

I installed mine without any check valves or whatever they're called whatsoever and I haven't found a need for them on my double-pipe system.  The pipes go straight in and out of each radiator.  I don't have a cauliflower.  I have a 2 pipe reservoir with bypass as in the Webasto manual "best option" and I don't have any problems with bleeding though I can't see any way around loosening the boiler top hose but that only required doing once so far and was easy.

Are you sure about that? That seems like an awful lot of expansion.

Edited by Flyboy
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1 hour ago, Flyboy said:

 

Are you sure about that? That seems like an awful lot of expansion.

I'll post the before & after pics if I can find them but it may take some time.  I posted here somewhere more details a little while ago.

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1 hour ago, Flyboy said:

 

Are you sure about that? That seems like an awful lot of expansion.

JG Guest say "On long exposed runs of pipework, the expansion of Speedfit Pipe when warm (1% on length between 20 to 82°C) can cause it to sag between clip fixings."

 

150 mm thermal expansion is what you would expect in a 15 metre run - so 6 inches in 50 feet.

 

 

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12 minutes ago, TheBiscuits said:

JG Guest say "On long exposed runs of pipework, the expansion of Speedfit Pipe when warm (1% on length between 20 to 82°C) can cause it to sag between clip fixings."

 

150 mm thermal expansion is what you would expect in a 15 metre run - so 6 inches in 50 feet.

 

 

Thanks for that.  It just seemed a lot to me.

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10 hours ago, TheBiscuits said:

JG Guest say "On long exposed runs of pipework, the expansion of Speedfit Pipe when warm (1% on length between 20 to 82°C) can cause it to sag between clip fixings."

 

150 mm thermal expansion is what you would expect in a 15 metre run - so 6 inches in 50 feet.

 

 

Many years ago I was working in South Africa as an advisor to a company building automotive cable harnesses. They had a huge problem with 'expansion' (harness growing / shrinking)

 

This resulted in the harness fixing clips not lining-up with the holes in the car body.

 

There could be several inches difference in harness length between a harness built in the morning and one built in the afternoon because of the 'growing' of the individual wires as the temperature increased (no air-con in the factory - just 'open doors').

 

We finally developed a 'sliding' fixing for them to take up the tolerances..

 

Temperature has some funny side-effects.

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I installed my system using Speedfit some months ago, using a central backbone under the floor with tees up to the radiators in copper because of tight bends and tidyness when pipes are in view. Speedfit is much quicker but I did have to allow for expansion of the pipes and used expansion sleeves which I think made it more time consuming. I have easy access to all the joints so I am hoping it will work out over time. In retropect I wished I had used copper throughout as when it gets up to full temperature the plastic becomes quite soft and if you had an overheat I am not sure what would happen. I used 22mm rubber hose from the engine room webasto to the underfloor pipes. I didn't consider just using automotive water hose for the main system but in hindsight that could be a good option if you hava an awkward route. Not exposed to sunlight it would last a good many years.

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32 minutes ago, Greenhorn said:

Thanks for all the reply’s 

 

so other than not needing the non return valves on the outlets back to cold line everything else looks ok? 
 

 

Yes, but I don't see any need for the isolation valve between the header tank connections.

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23 hours ago, Greenhorn said:

thanks for pointing that out tho as I’ve just noticed it says to put the balancing valve on the outlet  not the inlet as per my diagram 

It’ll make no difference which line you put it in. If it’s closed then there will be no flow through the cauliflower loop wherever you put it. 

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2 hours ago, Flyboy said:

Yes, but I don't see any need for the isolation valve between the header tank connections.

This is a webasto official recommendation. You close the valve when first commissioning the system which forces all the flow through the header tank. This gets gross embedded air out of the system more quickly.  When that is done, then the valve is opened for normal operation and most of the flow bypasses the header tank and flows more efficiently but there is still an opportunity for small amounts of air to escape up to the header tank. It is claimed to help bleeding the initial system quicker and easier.  It 's in the manual.

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6 minutes ago, system 4-50 said:

This is a webasto official recommendation. You close the valve when first commissioning the system which forces all the flow through the header tank. This gets gross embedded air out of the system more quickly.  When that is done, then the valve is opened for normal operation and most of the flow bypasses the header tank and flows more efficiently but there is still an opportunity for small amounts of air to escape up to the header tank. It is claimed to help bleeding the initial system quicker and easier.  It 's in the manual.

I've never had any connection between the the two pipes on the header tank so all the flow goes through it. Never had any problem bleeding it.

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2 hours ago, Flyboy said:

I've never had any connection between the the two pipes on the header tank so all the flow goes through it. Never had any problem bleeding it.

You wouldn't. You just get some extra bends which reduce the speed of the flow by a probably tiny amount which will only matter if you are operating at the limits of the tiny pump.

The bleeding problem occurs in the converse, where the valve has been eliminated and the two pipes to the header have been reduced to a single pipe.

 

Scenarios:

1. 1 pipe to header, no valve.  Hard to bleed.

2. 2 pipes to header, no valve.  Added drag to flow, header acts as radiator.

3. 2 pipes to header, with valve. Easier bleeding over [1], better flow in normal operation than [2].

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33 minutes ago, system 4-50 said:

You wouldn't. You just get some extra bends which reduce the speed of the flow by a probably tiny amount which will only matter if you are operating at the limits of the tiny pump.

The bleeding problem occurs in the converse, where the valve has been eliminated and the two pipes to the header have been reduced to a single pipe.

 

Scenarios:

1. 1 pipe to header, no valve.  Hard to bleed.

2. 2 pipes to header, no valve.  Added drag to flow, header acts as radiator.

3. 2 pipes to header, with valve. Easier bleeding over [1], better flow in normal operation than [2].

As you say it’s stated within the Webasto manual so that’s why I included the valve. 

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