refilling CH system

[Boaty McBoaty]

Do I refill an empty CH system through the CH expansion tank??

 

I have a Webasto heating the radiators on Boaty. I think the CH circuit also runs through the calorifier somehow to give me hot water.  Have decided I want to re-carpet the side walls which means draining down system and removing the radiators but before I do that I want to be sure I know how to top the system back up .  I assume I can just fill it up through the expansion tank?  

 

Thanks 🙂

[Tony Brooks]

18 minutes ago, Boaty McBoaty said:

Do I refill an empty CH system through the CH expansion tank??

 

I have a Webasto heating the radiators on Boaty. I think the CH circuit also runs through the calorifier somehow to give me hot water.  Have decided I want to re-carpet the side walls which means draining down system and removing the radiators but before I do that I want to be sure I know how to top the system back up .  I assume I can just fill it up through the expansion tank?  

 

Thanks 🙂

 

I don't think you will have to drain down unless it is a gravity system with a pipe at the top and bottom of the radiator. I suspect that you could get a couple of blocks of a suitable size, just loosen the couplings on the radiator valve, so you can lift each rad off its bracket, twist forward and lay it on the blocks.  A little liquid may leak out, but a couple of old towels on the floor should  deal with that.

 

If you have an open expansion tank, then yes, you do fill through it.

[BEngo]

Yes, fill via the expansion tank. It will speed things up if you  let the air out with the radiator bleed valves if fitted. 

You may need to crack one or both of the calorifier coil fittings if the calorifier loop does not self-fill. Check it again about 48 hours after filling.

 

Use 50% car antifreeze already diluted or central heating mixture as sold by Screwfix et al.   Never put neat antifreeze in as it tends to settle at the bottom of the pipework and hinder circulation. Check the stiff you fancy is compatible with your Webasto.

 

N

[Boaty McBoaty]

Many thanks indeed both.  Very useful. 

 

Tony, mine are on a normal system with in/out valves at the bottom I think and plumbed in with speedfit fittings and pipes. And yes the expansion tank is about A4 size with a loose lid on.   Like the idea of just being able to keep system flooded although with the narrow corridor not sure how easy it will be to work around them when 'detached' so to speak. 

 

BEngo.  Not sure I know enough yet to understand the calorifier loop system yet but will take a look tonight as on board.  I know the rads are plumbed in using speedfit pipes throughout the cabin so presumably I should just be looking for a part of the speedfit loop that connects in/out of the calorifier and if need be crack open these fittings to let air in when refilling you mean?  

 

Out of interest do you know if all wall rads have the same pitch when it comes to hanging brackets?  Just wondering if I take them off a) it will be easier to do the carpet work but b) there is an opportunity to install sparkly new rads maybe if the wall brackets are a standard pitch/type?  

[Tracy D'arth]

2 minutes ago, Boaty McBoaty said:

Many thanks indeed both.  Very useful. 

 

Tony, mine are on a normal system with in/out valves at the bottom I think and plumbed in with speedfit fittings and pipes. And yes the expansion tank is about A4 size with a loose lid on.   Like the idea of just being able to keep system flooded although with the narrow corridor not sure how easy it will be to work around them when 'detached' so to speak. 

 

BEngo.  Not sure I know enough yet to understand the calorifier loop system yet but will take a look tonight as on board.  I know the rads are plumbed in using speedfit pipes throughout the cabin so presumably I should just be looking for a part of the speedfit loop that connects in/out of the calorifier and if need be crack open these fittings to let air in when refilling you mean?  

 

Out of interest do you know if all wall rads have the same pitch when it comes to hanging brackets?  Just wondering if I take them off a) it will be easier to do the carpet work but b) there is an opportunity to install sparkly new rads maybe if the wall brackets are a standard pitch/type?  

If the make and size is the same then likely the same brackets and positions but depends how old the rads are. If a different size or make then no way.

[Boaty McBoaty]

Rads are dated and the chap who fitted out Boaty did it in back in 1990 so likely to be rads from back then.  Probably regular B&Q household types but I will try and measure the pitch at least and compare to some new rads.  Tempted to bite the bullet and plan to install new brackets and rads but current ones work fine but just look a bit dated thats all.  Plus the job is to upgrade the carpets which for me is a big enough project right now so might plan to make it easy and reinstall existing for now and update them in a year or two! 

[Tracy D'arth]

New ones won't work any better than old ones.  A coat of paint perhaps?

[BEngo]

4 hours ago, Boaty McBoaty said:

so presumably I should just be looking for a part of the speedfit loop that connects in/out of the calorifier and if need be crack open these fittings to let air in when refilling you mean?  

That is it  yes, except you want to let the air out of the pipes and calorifier🙂

 Yoh can find the route easily.  Put the Webastardo on and turn off the radiators.  There will be a pipe going to the calorifier that gets hot.  That is the inlet pipe.  In due course one of the other  pipes will start to warm up.  That is the outlet pipe.

 

N

Edited September 19 by BEngo
Add last bit

[Boaty McBoaty]

Great help everyone, many thanks indeed. 

[JoeC]

I flushed my system recently, took the radiators off and invert flushed them with hose and a tap to get rid of any crud in the bottom - only a little brown liquid came out with no rust or sludge. I used PTFE white tap when connection the radiators back up.

 

As others have said, use pre-diluted car anti-freeze - my Webasto said to only use IAT mono ethylene antifreeze - which I diluted to about 40%. Poured it in via the expansion tank and then opened up the lowest bleed point to get it to flow to that point. Then bled each radiator until all air came out - keep an eye on the expansion tank and top up if it gets near the low mark otherwise you could be bringing air back into the system if the tank empties. Then switched on the Webasto to do the automatic final system bleed itself (the Webasto should bleed itself). All worked perfectly and I have run it a few times to make sure.