Webasto heating problem

[rgriffiths]

So ... after a break from trying to resolve this I have got under the bed and fitted a couple of valves. I closed 1 and left 2 open and bled from the bleed valve. Then closed 2 and and opened 1 and bled again. I have no idea if this is good practice or not but it seemed to work and now get piping hot water. The strange thing is that I watched very carefully for any air to come out. I was bleeding into a container with the hose submerged below the surface so I would see any bubbles but none. Then again I might have missed it and maybe it doesn't need much to scupper the system.

 

So all sorted and set for a warm winter. Thanks to all as ever - especially Mike - for all your help and advice.

 

Edited October 24, 2018 by rgriffiths

[Sea Dog]

11 minutes ago, rgriffiths said:

So ... after a break from trying to resolve this I have got under the bed and fitted a couple of valves. I closed 1 and left 2 open and bled from the bleed valve. Then closed 2 and and opened 1 and bled again. I have no idea if this is good practice or not but it seemed to work and now get piping hot water. The strange thing is that I watched very carefully for any air to come out. I was bleeding into a container with the hose submerged below the surface so I would see any bubbles but none. Then again I might have missed it and maybe it doesn't need much to scupper the system.

 

So all sorted and set for a warm winter. Thanks to all as ever - especially Mike - for all your help and advice.

 

Good job! Now, adjusting a valve (they should be full flow types, but it may not matter) in either the red or blue lines will allow you throttle the flow to balance the flow between the radiator circuit and the calorifier, as too much will return hot water to your webasto and cause it to short cycle (shut down early and restart) which, as well as meaning you don't get full output from your radiators, is a life shortener for these systems. Too little flow through the calorifier will mean it's slow to heat the hot water, so the balance is important.

[rgriffiths]

All valves are fully open (apart from the bleed of course). I had an interesting chat with a Webasto engineer who said (as you did Sea Dog) that we want the system to 'overwork'. You do not want the unit to slow down at any time as they are designed to run and not idle. Therefore I have set the valves all fully open so water is not restricted. It may alter what gets hot first I suppose but wanted to keep the system work as hard as it can. Seems to be working.

[MtB]

2 hours ago, rgriffiths said:

So ... after a break from trying to resolve this I have got under the bed and fitted a couple of valves. I closed 1 and left 2 open and bled from the bleed valve. Then closed 2 and and opened 1 and bled again. I have no idea if this is good practice or not but it seemed to work and now get piping hot water. The strange thing is that I watched very carefully for any air to come out. I was bleeding into a container with the hose submerged below the surface so I would see any bubbles but none. Then again I might have missed it and maybe it doesn't need much to scupper the system.

 

So all sorted and set for a warm winter. Thanks to all as ever - especially Mike - for all your help and advice.

 

 

I suspect that in draining to fit the valves then re-filling, you cleared an air lock anyway. But whatever, well done! Getting something working with one's own fair hand is deeply rewarding, innit!

 

And thanks for coming back and updating your thread with the good news. Not everyone does.