Maximum deviation from horizontal before air lock?

[crosbie]

Yes, good practice avoids high points, so in pursuit of good practice (and a lack of problems), I need to know what a 'high point' is in terms of rise & fall height, and how high a high point has to be that a vent should be incorporated where one occurs.

 

[Last Plumber]

I agree that there's no need to be sarcastic (I intended none). I'm not here for a flame war, but for informed advice & opinion.

I agree that any air pocket could cause an issue, and that no size of air lock is ok.

It's at what height of rise & fall that these things occur that's the mystery. :-/

I agree that there's no need to be sarcastic (I intended none). I'm not here for a flame war, but for informed advice & opinion.

I agree that any air pocket could cause an issue, and that no size of air lock is ok.

It's at what height of rise & fall that these things occur that's the mystery. :-/

There is no set height. Each system ( although a lot use the same design ) is unique.

They will all behave slightly differently.

Different rads/emitters, pipe sizes, the number of fittings and bends, lengths of tube, valves, boilers etc, all have differing flow rates and frictional resistances to contend with amongst many other things. Therefore, there is no "rule of thumb" for poor practice being acceptable. It's best not to try.

If it is not level or rising to a vent point, it will collect air/gas.

 

[joni os]

Shutting down rads. or back filling at mains pressure are both solutions to remove air and promote flow. How these are defined by "lack of problems".will relate to the definition you are seeking.

 

[crosbie]

Thanks for the tips. I knew about the mains filling one, but shutting down rads to maximise flow through certain parts of the circuit is a good one.

As to the key heights, unless someone with the requisite figures or formula posts them (eventually), I guess it may be a matter of setting up an outdoor experiment with a 2m high tank of coloured water, and transparent 15mm dia polythene pipe strung out over the ground with 'rises & falls' of varying heights. Then one can see at what heights air-pockets remain, and what height of rise & fall prevents flow entirely.

Place your bets...

 

[crosbie]

For the experiment, I should add that as the circuit is at 1m head pressure, then the supply tank (simulating a circulator of 5m head) would have to be at 3-3.5m and the end of the pipe would have to go up from the ground to a 1m high outflow.

 

[SimonG]

Thought this had been discussed on a previous thread?

 

[Last Plumber]

For the experiment, I should add that as the circuit is at 1m head pressure, then the supply tank (simulating a circulator of 5m head) would have to be at 3-3.5m and the end of the pipe would have to go up from the ground to a 1m high outflow.

You've misunderstood the concept entirely !

 

[SimonG]

Not a full deck. Must be some sort of engineer.

Sometimes things don't need over thinking.

 

[Best]

A waste of time. The system will work anyhow, unless you create serious high spots, although even then it probably will work.
As I said earlier, have a sealed heating system installed if possible, so that air will generally not be a problem once it is removed on any fill up.
Then install all pipework to give consideration for where the air can escape to, so as to do a reasonable job. If hard copper pipework can be installed, then have it done. But plastic plumbing or soft microbore copper have worked for years and still will do the job.
By the time you waste thinking about it, asking questions and experimenting, - you could have the job done properly and with best materials and methods

 

[jonnyswamp]

Knock yourself out fella
Just make sure you post your video on youtube and supply a link

 

[Dotty]

I think the point has been made now.

Thread closed.