Idea, but need to check something...

[Jen-in-Wellies]

7 minutes ago, BWM said:

I was going to suggest a sight glass but thought it would quickly become unreadable due to the nature of the fluid in heating systems, i suspect that the above would end up the same. 

 

An ex boating neighbour had an aluminium header tank for their heating system with an external plastic sight tube and this is exactly what happened. It eventually became entirely opaque. I suppose an open ended one and a scrub with a small bottle brush every once in a while could help prevent this. I think the float with an indicator stick @robtheplod proposes is a better solution. 

[Tony Brooks]

14 minutes ago, BWM said:

I was going to suggest a sight glass but thought it would quickly become unreadable due to the nature of the fluid in heating systems, i suspect that the above would end up the same. 

I think the same when you think about the tall Alde header tanks, but it was just an arguably better way without drilling the tank etc.

[David Mack]

4 hours ago, Tony Brooks said:

I think the same when you think about the tall Alde header tanks, but it was just an arguably better way without drilling the tank etc.

My translucent Alde header tank was too opaque to see the water level. I always had to remove the pump and do the wet finger test to see if it was full enough.

[Opener]

On 17/08/2021 at 09:29, MtB said:

 

I think the taper is a parallax effect in the taking of the photo. I have what I think is the same make and model of header tank in my own boat and mine is exactly parallel. 

 

Mine came with a lid though! 

 

So, once you have solved the problem of how soluble your proposed float is in water/auntie-freeze, you drill a suitable sized hole in said lid so that your 'vertical'/ indicator sticks and slides through it. Much more stable.

[cuthound]

On 18/08/2021 at 12:54, David Mack said:

My translucent Alde header tank was too opaque to see the water level. I always had to remove the pump and do the wet finger test to see if it was full enough.

 

On my Webasto system I put a torch under the translucent header tank which nicely illuminates the level.

 

One day when I'm really bored I might even wire up a lamp and push button, to make checking the level even easier 😁

[ditchcrawler]

2 hours ago, cuthound said:

One day when I'm really bored I might even wire up a lamp and push button, to make checking the level even easier 😁

Now why didn't I think of doing that