Radiator without bleed valve

[dave mackie]

I've a radiator that has a pin hole in it and I'm going to repair it, however there is no bleed valve at the top of the radiator and I was wondering how I would go about bleeding the system ( webasto Evo top ). Any ideas please.

[Tonka]

1 minute ago, dave mackie said:

I've a radiator that has a pin hole in it and I'm going to repair it, however there is no bleed valve at the top of the radiator and I was wondering how I would go about bleeding the system ( webasto Evo top ). Any ideas please.

What is in the holes that are at the top of the radiators. Are you sure they are not self bleeding ?

[dave mackie]

There's nothing at the top of the rad, it's a completely sealed unit apart from the two valves at the bottom .

[ditchcrawler]

1 minute ago, dave mackie said:

There's nothing at the top of the rad, it's a completely sealed unit apart from the two valves at the bottom .

Are you sure there are not plugs in there, most come with a tapping at each corner

[Sea Dog]

16 minutes ago, dave mackie said:

There's nothing at the top of the rad, it's a completely sealed unit apart from the two valves at the bottom .

Hmm, air usually rises in water, so I'm not sure how you'd ever expel all the trapped air to get that rad to be hot all the way to the top. Instead of repairing the pin hole it it (and there may well be more coming along soon if it's been corroding from the inside) why not take the opportunity to replace the old unvented rad with a new one that you can bleed?

Edited July 10, 2023 by Sea Dog
Changed the text back to unvented from invented.

[GUMPY]

I've never seen a radiator without some way of getting the air out.

Its got to be worth a picture.

[David Mack]

There's no way you can effectively repair a radiator that has corroded through. And even if you do, the one pinhole that has corroded right through is indicative of others that are almost as bad, so you will soon have another.

Time to bite the bullet and fit a new radiator (with bleed valve). And make sure you have the right amount of inhibitor in the system to prevent further corrosion.

[system 4-50]

Some rads have air bleeeeds in the back rather than the ends!

[Batavia]

20 minutes ago, system 4-50 said:

Some rads have air bleeeeds in the back rather than the ends!

We had one like this many years ago and the previous occupier had managed to break off the head of the bleed screw flush with the radiator, with the result that it was more or less invisible.

[blackrose]

1 hour ago, dave mackie said:

I've a radiator that has a pin hole in it and I'm going to repair it, however there is no bleed valve at the top of the radiator and I was wondering how I would go about bleeding the system ( webasto Evo top ). Any ideas please.

 

If you want to bleed the system just take the cap off the header tank and remove a hose from the Webasto with a bucket underneath. You might want to have a wetvac handy.

 

I'm assuming there is a header tank in the system and it's higher than the radiators.

[ditchcrawler]

23 minutes ago, blackrose said:

 

If you want to bleed the system just take the cap off the header tank and remove a hose from the Webasto with a bucket underneath. You might want to have a wetvac handy.

 

I'm assuming there is a header tank in the system and it's higher than the radiators.

How will that get the trapped air out of the radiators?

[blackrose]

50 minutes ago, ditchcrawler said:

How will that get the trapped air out of the radiators?

 

Just loosen a connection at/near the the top of that rad with a spanner.

 

The other way of doing it is to take off the flow and return hoses from the Webasto and suck all the water out of the system with the wetvac that I said might come in handy.

 

Anyway, if trapped air in the radiator (just one without a bleed valve as I read it) is such an issue then how on earth did someone manage to get the water/antifreeze into that rad in the first place?

 

Once the OP takes the radiator off to replace or repair it that should remove any trapped air! 😋  I think it needs a bleed valve.

Edited July 10, 2023 by blackrose

[Tony Brooks]

4 minutes ago, blackrose said:

 

Just loosen a connection at/near the the top of that rad with a spanner.

 

Anyway, if trapped air in the radiator (just one without a bleed valve as I read it) is such an issue then how on earth did someone manage to get the water into that rad in the first place?

 

Who seems not to have read the whole thread

[blackrose]

3 minutes ago, Tony Brooks said:

 

Who seems not to have read the whole thread

 

??? Not me. I read the whole thread.

 

Perhaps I'm just reading it differently to you Tony. Had you considered that different people interpret things differently?

Edited July 10, 2023 by blackrose

[Tony Brooks]

2 hours ago, dave mackie said:

There's nothing at the top of the rad, it's a completely sealed unit apart from the two valves at the bottom .

 

I think that say that as far as the OP is concerned there are no fittings in the top, I would agree that sounds unlikely, but as neither of us have seen it who knows.

[system 4-50]

We need a pic!

[dave mackie]

There's No fittings/ bleed valve at top of rad only the feed in and out ( with valves ) at the bottom of rad

[Sea Dog]

2 minutes ago, system 4-50 said:

We need a pic!

A pic of it in the skip or of the new one installed might be the most effective resolution of the OPs issue... 

[system 4-50]

There must be something!  A blank, something.

 

[David Mack]

2 minutes ago, dave mackie said:

There's No fittings/ bleed valve at top of rad only the feed in and out ( with valves ) at the bottom of rad

Then the only way of bleeding it is to slacken off the pipe connections at either end, lift the radiator out of its brackets (assuming the pipework is loose enough to allow this) then laying it down on the floor, so that the top of the radiator is lower than the pipe connections. I have in the past done this to decorate behind a radiator without draining the system down, but I wouldn't like to rely on it for bleeding.

[Sea Dog]

Just now, system 4-50 said:

There must be something!  A blank, something.

 

A radiator without a bleed valve? Haven't we all drawn a blank?

[Tracy D'arth]

Some round top radiators (Myson) have a bleed nipple hidden in the folded end of the radiator or they have a nipple on the back face of the radiator aprox, 15cm from one end. A double such radiator  will have it between the panels, very difficult to get a key onto.

[hovrin]

Maybe you could extend the pipe work at each end upwards and then fit the radiator upside down -  just a thought.😇

Edited July 11, 2023 by hovrin

[Ronaldo47]

Mounting it upside-down would mean that hot water entering would remain at the top and  flow straight out again, leaving the water at the bottom of the radiator cold. You would need to mount it sideways with the hot entering at the higher port.

[Tracy D'arth]

It will have a bleed point, you have just not found it yet.  No point in fixing pin holes, its corroded, fit a new one.