A simple one for a Sunday morning..

[shabbaranks]

Hi guys,

Whats the proper name for the valves inwhich you connect up a hose or something to to empty the radiators? As I understand it you have the bleed valve which is at the top but what about the valves which are bolts\valves which are located at the bottom?

Also I notice where we are currently (new build 97) these are on all the downstairs radiator obviously to completely empty the system - would you have them on all?

And with regards to the bleed valves - self bleed or manual? And Im I correct in thinking you have a self bleed ad the highest point of the system too? And are there any specific requirements to its location?

Thanks
Shabba!!

 

[PrenticeBoyofDerry]

They are called Drain off Valves.

Untitled

• PrenticeBoyofDerry
• 8 Jan 2012
• 1

 

[shabbaranks]

Great thanks, I notice you can get ones which integrate with the return pipes - is it possible to buy ones which just adapt to the valves or are they complete units?

Also - would you have them on all rads? Thanks again

 

[PrenticeBoyofDerry]

they should be installed at the lowest point of the system possible otherwise they are a bit pointless.
You can get them integrated with the rad valve normally on the locksheild side, so one unit or you can buy them as a separate unit.

 

[shabbaranks]

Yeah I knew that, but what I am saying is I have seen examples where they are installed on all radiators (if in a house just downstairs) and examples where they are just installed in a single location (at the lowest point of the system). This is kinda where I am going... I guess if they were on all rads you could drain the complete system from them, if they were just at a single point you could drain the system apart from each rad loop and you would have to drain that from the valves/bleed points as opposed to the drain valves.

 

[PrenticeBoyofDerry]

If I get you right?
The lowest point of the central heating system may not always be at a radiator depending how that system is run.
There will also be a drain off on the rising main (cold water supply) so don't get these confused.

You could only really drain a total system off from the lowest point even if a drain off were fitted to each rad. So unless each rad was at a low point it would not be needed.
If you wanted to just remove one rad say from system you would normally close all the other rad valves to prevent them from emptying.

 

[picasso]

If the central heating is done on drops from upstairs then you would need a drain off cock on every drop, if the heating circuit is just one run on the ground floor you would just need one drain for the whole house.

 

[PrenticeBoyofDerry]

If the central heating is done on drops from upstairs then you would need a drain off cock on every drop, if the heating circuit is just one run on the ground floor you would just need one drain for the whole house.

valid point

 

[Charnwood]

They are sometimes called MT cocks.
In 40 years I've never found out what MT stands for, unless it is a b@stardisation of 'empty'.

Anyone any ideas?

The lowest point of the central heating system may not always be at a radiator

The lowest point of a system is rarely at a radiator. There is almost always pipework below radiators, therefore the lowest point will almost certainly be on a run of pipework below the lowest rad.

 

[shabbaranks]

Our lowest point is a rad - well the return running from the rad back to the loft. Nothing gets as low as the floor as all our runs are from the loft and back up again in a bungalow.

 

[PrenticeBoyofDerry]

Some properties do have cellars though or even accessible crawl spaces beneath them, where drain offs can be found.

 

[shabbaranks]

Where would you put the auto bleed valve? Is it possible to put it at the end of a pipe run?

Cheers

 

[PrenticeBoyofDerry]

They go on rads, why would you feel you need to install one?

 

[shabbaranks]

I thought they go at the highest point? So if theres air in the system it gets removed? Or have I mis-interpreted them?

Thanks

 

[Agile]

If you wanted to just remove one rad say from system you would normally close all the other rad valves to prevent them from emptying.

At least one other professional knows that then!

When I said that recently on a forum I got a lot of negative coments.

But I expect they were from the cowboys who charge by the hour and like to spin out the job.

On the other hand I do everything on a fixed price basis and its not in my interest to take a long time.

Tony