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Convert webasto header tank to pressured system


Sarah-H

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Hi Everyone,

 

I am hoping to convert my webasto system which is currently utilising a header tank to a pressurised system.  I have purchased some bits that were recommended on another thread (Which I now cannot find!)

 

Expansion Tank

Evolve Expansion Vessel Kit

Auto Air Vent - Bottle Vent

 

I am just a little confused on adding the Expansion Vessel Kit into the system. (especially the Gold 4 way manifold)

 

Does anyone have any guidance on what connects to what on the above image? or does anyone have any images of a pressurised system so I can try and follow it?

 

My webasto seems to be a typical set up - 'Flow' from Webasto to Radiators and then 'Return' via a Header tank and a calorifier back into the webasto using 22mm speedfit pipe.

 

Many thanks

Sarah.

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All the new fittings are for 15mm pipe, you will have to site the expansion bottle, manifold and fill loop somewhere where you have 15mm pipe.

 

The expansion bottle screws into the large tapping on the manifold, the manifold is inserted into the pipe run using a tee and the female cross connection. You  connect the fill loop to the male cross connection and using another tee connect the other tap end of the fill loop to the cold water pipe.

You then need to run a drain from the PRV outlet (under the red knob) either overboard or into a safe place for it to discharge very hot steam in the event of thermostat failure.

 

So you need 2 15mm tees in addition to what you have. And a male 1/2"Bsp adaptor to 15mm and  pipe for the PRV waste run.

 

 

Edited by Tracy D'arth
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2 hours ago, Tracy D'arth said:

And a male 1/2"Bsp adaptor to 15mm

Hi Tracy,

 

Thanks so much for your reply. I think I should be able to manage that but just one quick question if I may. What is the 'male 1/2"Bsp adaptor to 15mm' you referred to used for? Is this to connect the filling loop to the male connection? (If so, can I just use a piece of copper pipe between the 2 as they are both compression?)

 

Also, does it matter if the manifold is inserted into either the flow or return of the webasto?

 

Many thanks

Sarah.

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12 minutes ago, Sarah-H said:

Hi Tracy,

 

Thanks so much for your reply. I think I should be able to manage that but just one quick question if I may. What is the 'male 1/2"Bsp adaptor to 15mm' you referred to used for? Is this to connect the filling loop to the male connection? (If so, can I just use a piece of copper pipe between the 2 as they are both compression?)

 

Also, does it matter if the manifold is inserted into either the flow or return of the webasto?

 

Many thanks

Sarah.

The male 1/2" BSP adaptor is for the PVR outlet so that you can put a safety discharge pipe on it, plastic will do.

 

Matters not if its flow or return.

Edited by Tracy D'arth
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55 minutes ago, David Mack said:

 

Why?

It's usually to stop air entering the system hence alieviating the need to bleed radiators? However if system is correctly installed its not needed, I never bleed my rads for instance. 

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On 15/09/2020 at 13:41, David Mack said:

 

Why?

To make the system more complicated than it needs to be, the greater pressure makes leaks more likely. Domestic pressurised systems have much greater need of plumber visits than the old non pressurised systems, which often went decades between plumber visits.

Edited by Detling
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On 15/09/2020 at 13:38, Tracy D'arth said:

The male 1/2" BSP adaptor is for the PVR outlet so that you can put a safety discharge pipe on it, plastic will do.

 

Matters not if its flow or return.

Hi Tracy,

 

Thank you so much for your help. I can definitely follow that so will be tackling it this weekend!

 

Many thanks again!

Sarah

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On 16/09/2020 at 18:04, Tracy D'arth said:

The OP probably wants the space occupied by the header tank for some other purpose.

I do agree that making it more complicated is not the boat way of doing things but it is a valid option.

Yes this is partially the case. Unfortunately the previous owner fitted 2 towel rads that are approx 8ft in height!! and there is absolutely nowhere in the boat that a header tank can go (not above this height anyway) so the towel rads were only ever hot at the bottom. I know I could remove these rads and fit standard towel rads but they were custom made (height and width) and no standard rad will fit either the space they occupy or the pipework supplying them so this means also replacing the piework, which means dismantling cupboards etc to access the pipework.

 

After speaking with a couple of different engineers at a a local marina bar they both said they always fit pressurised now and almost never fit using the header tank method as it is the Webasto preferred method and they have less call outs for air inclusion into the system. Another couple of boaters said they are constantly topping up header tanks which for one was a PITA due its location inside/top a cupboard. (Apparently they had an engineer come out and check for leaks and confirmed that there were no leaks in the system and was likely just evaporation) Why would the header tank keep evaporating so much out of curiosity?

 

So for me the switch to pressurised is far simpler and cheaper than removing the 2 custom towel rads and half of the 2 bathrooms furniture. (One marine engineer quoted me approximately £1200-£1500 to swap out the towel rads whereas the pressurised kit cost approx £30.

 

Mant thanks again for all your help!

Sarah.

 

 

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16 minutes ago, Sarah-H said:

Yes this is partially the case. Unfortunately the previous owner fitted 2 towel rads that are approx 8ft in height!! and there is absolutely nowhere in the boat that a header tank can go (not above this height anyway) so the towel rads were only ever hot at the bottom. I know I could remove these rads and fit standard towel rads but they were custom made (height and width) and no standard rad will fit either the space they occupy or the pipework supplying them so this means also replacing the piework, which means dismantling cupboards etc to access the pipework.

 

After speaking with a couple of different engineers at a a local marina bar they both said they always fit pressurised now and almost never fit using the header tank method as it is the Webasto preferred method and they have less call outs for air inclusion into the system. Another couple of boaters said they are constantly topping up header tanks which for one was a PITA due its location inside/top a cupboard. (Apparently they had an engineer come out and check for leaks and confirmed that there were no leaks in the system and was likely just evaporation) Why would the header tank keep evaporating so much out of curiosity?

 

So for me the switch to pressurised is far simpler and cheaper than removing the 2 custom towel rads and half of the 2 bathrooms furniture. (One marine engineer quoted me approximately £1200-£1500 to swap out the towel rads whereas the pressurised kit cost approx £30.

 

Mant thanks again for all your help!

Sarah.

 

 

About £1300 to swap a couple of rads??!!  So if the new parts are a couple of hundred quid then that leaves £1100 for labour.  At £75/hour that is 14 hours, so a day per rad.  My wife sometimes complains I’m a bit slow at diy, well now I can prove I am very fast compared to the professionals.

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7 hours ago, Chewbacka said:

About £1300 to swap a couple of rads??!!  So if the new parts are a couple of hundred quid then that leaves £1100 for labour.  At £75/hour that is 14 hours, so a day per rad.  My wife sometimes complains I’m a bit slow at diy, well now I can prove I am very fast compared to the professionals.

I agree but unfortunately it's mainly the labour involved in removing and rebuilding the cupboards that surround the towel rads. (Think of abuilt in fridge housing) The pipework for the rads is underneath/behind these and they need to be removed to do the work. I did wonder why he couldn't just use the pipework that is on show for the existing rads to extend out to the new rads but he said it's too short to connect new pipework to and as I really like the custom one's I'm happy to switch to pressurised system and save all the grief and expense!

 

Many thanks

Sarah

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3 hours ago, Sarah-H said:

I agree but unfortunately it's mainly the labour involved in removing and rebuilding the cupboards that surround the towel rads. (Think of abuilt in fridge housing) The pipework for the rads is underneath/behind these and they need to be removed to do the work. I did wonder why he couldn't just use the pipework that is on show for the existing rads to extend out to the new rads but he said it's too short to connect new pipework to and as I really like the custom one's I'm happy to switch to pressurised system and save all the grief and expense!

 

Many thanks

Sarah

Perfectly good reasoning.  Go for it. Don't forget antifreeze with corrosion inhibitor in the water at 30% when you fill up but how you are going to get it into the system will be tricky. I would suggest you fill a radiator with 80% first, then finish the fill with the fill loop in the kit. The tap end of the loop connects to the cold water feed.

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10 hours ago, Tracy D'arth said:

Perfectly good reasoning.  Go for it. Don't forget antifreeze with corrosion inhibitor in the water at 30% when you fill up but how you are going to get it into the system will be tricky. I would suggest you fill a radiator with 80% first, then finish the fill with the fill loop in the kit. The tap end of the loop connects to the cold water feed.

Hi Tracy,

 

Yes I have purchased the antifreeze etc and a radiator filling kit so as you suggested I will fill most of the system this way and then pressurise the last part. I was all set to be up early tomorrow and get stuck in but turned my webasto on this morning only to get a high voltage error! :o(

 

I have had a look through here and google for similar but can only find issues relating to low voltage. I have a multimeter I purchased when I purchased the boat and checked at the batteries and they were 13.2V but my webasto error was showing 16.5V so I think the conversion is going to have to go on hold in case I need to remove the webasto for repair. (No point spending out on antifreeze etc only to have to drain it down if the webasto has to be removed shortly!) - If I do end up removing it I think I will add a couple of ball valve/taps just before the webasto unit for future servicing! Oh well, 2 steps forward, one step backwards!! :o(

 

Thank you again for all your help. I do at least now feel confident making the required changes if I can get the webasto fixed.

Sarah.

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9 hours ago, Sarah-H said:

Hi Tracy,

 

Yes I have purchased the antifreeze etc and a radiator filling kit so as you suggested I will fill most of the system this way and then pressurise the last part. I was all set to be up early tomorrow and get stuck in but turned my webasto on this morning only to get a high voltage error! :o(

 

I have had a look through here and google for similar but can only find issues relating to low voltage. I have a multimeter I purchased when I purchased the boat and checked at the batteries and they were 13.2V but my webasto error was showing 16.5V so I think the conversion is going to have to go on hold in case I need to remove the webasto for repair. (No point spending out on antifreeze etc only to have to drain it down if the webasto has to be removed shortly!) - If I do end up removing it I think I will add a couple of ball valve/taps just before the webasto unit for future servicing! Oh well, 2 steps forward, one step backwards!! :o(

 

Thank you again for all your help. I do at least now feel confident making the required changes if I can get the webasto fixed.

Sarah.

If you fit valves make sure that they are full bore to get full flow, many ball valves are very restrictive.

Try disconnecting it from the power for a while, it may reset itself. Do a web search, someone may know.

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