A question for my brother, who hasn't worked out how to access usegroups.

He has a Worcester Bosch boiler he is about to connect up, but realises that
he doesn't understand how the 'Flow' and 'Return' pipes are identified.
His sytem has an external pump. He reasons that 'flow' is the pipe connected
to the output of the pump, and 'Return' is the pipe entering the pump.

I have a combi, where of course the 'Flow' pipe leaves the combi carrying
the
CH water away, and the 'Return' pipe brings the CH water back in to be
warmed
up again.

These two definitions have opposite meanings for the CH pipes at the
boiler/combi.
Which definition is correct for a boiler?

Andy.

In message , andrewpreece
writes
A question for my brother, who hasn't worked out how to access usegroups.

He has a Worcester Bosch boiler he is about to connect up, but realises that
he doesn't understand how the 'Flow' and 'Return' pipes are identified.
His sytem has an external pump. He reasons that 'flow' is the pipe connected
to the output of the pump, and 'Return' is the pipe entering the pump.

I have a combi, where of course the 'Flow' pipe leaves the combi carrying
the
CH water away, and the 'Return' pipe brings the CH water back in to be
warmed
up again.

These two definitions have opposite meanings for the CH pipes at the
boiler/combi.
Which definition is correct for a boiler?

If you think about it, water can only flow one way round the system, it
doesn't matter whether it's through the pump or boiler

Flow is out of the boiler and return is back into the boiler. If his
pump is indicating the other way around, then it's back to front

--
geoff

"raden" wrote in message
...
In message , andrewpreece
writes
A question for my brother, who hasn't worked out how to access usegroups.

He has a Worcester Bosch boiler he is about to connect up, but realises
that
he doesn't understand how the 'Flow' and 'Return' pipes are identified.
His sytem has an external pump. He reasons that 'flow' is the pipe
connected
to the output of the pump, and 'Return' is the pipe entering the pump.

I have a combi, where of course the 'Flow' pipe leaves the combi carrying
the
CH water away, and the 'Return' pipe brings the CH water back in to be
warmed
up again.

These two definitions have opposite meanings for the CH pipes at the
boiler/combi.
Which definition is correct for a boiler?

If you think about it, water can only flow one way round the system, it
doesn't matter whether it's through the pump or boiler

Flow is out of the boiler and return is back into the boiler. If his
pump is indicating the other way around, then it's back to front

Aah, but flow OUT of the pump ( flow ) is flow INTO the boiler ( return ).
So is the pipe leaving the pump in the direction of flow called FLOW,
because if it's all relative to the pump, then the pipe entering the pump
must be labelled RETURN, yet it is the same pipe that carries water OUT
of the boiler. Looking at Flow/Return from the pump's point of view ( i.e
flow=out,
return=in ) gives a different labelling of the pipes than looking at it
from the boiler's point of view.

All a bit metaphysical, I imagined that it is always referenced to the
boiler/combi,
not an external pump, but my bro' is always thinking up imaginary problems
and
I can't argue what the correct termnology is by force of logic.

Andy.

andrewpreece wrote:
Aah, but flow OUT of the pump ( flow ) is flow INTO the boiler ( return ).
So is the pipe leaving the pump in the direction of flow called FLOW,
because if it's all relative to the pump, then the pipe entering the pump
must be labelled RETURN, yet it is the same pipe that carries water OUT
of the boiler. Looking at Flow/Return from the pump's point of view ( i.e
flow=out,
return=in ) gives a different labelling of the pipes than looking at it
from the boiler's point of view.

All a bit metaphysical, I imagined that it is always referenced to the
boiler/combi,
not an external pump, but my bro' is always thinking up imaginary problems
and
I can't argue what the correct termnology is by force of logic.

Aristotle style reasoning (IOW without looking at an actual pump to
check reality matches speculation - the pump is in the loft after all):

Is the pump labelled 'flow' and 'return'? The term 'return' makes sense
to a boiler. The pump presumably does not have a preordained plan of if
the water it is pumping will return or not. I would expect an arrow (or
'in' and 'out') on the pump instead of 'flow' and 'return'.

I am not a plumber. We need an engineer and fewer
scientists/philosophers. I am curious to know the real answer...

Rem

andrewpreece wrote:

Flow is out of the boiler and return is back into the boiler. If his
pump is indicating the other way around, then it's back to front


Aah, but flow OUT of the pump ( flow ) is flow INTO the boiler ( return ).

Whoa there! Firstly forget about the pump. Flow and return are terms
relative to the boiler. Hot water comes out of the flow, goes to all the
rads / cylinder(s, and is then piped back to the return of the boiler.

So is the pipe leaving the pump in the direction of flow called FLOW,
because if it's all relative to the pump, then the pipe entering the pump
must be labelled RETURN, yet it is the same pipe that carries water OUT
of the boiler. Looking at Flow/Return from the pump's point of view ( i.e
flow=out,
return=in ) gives a different labelling of the pipes than looking at it
from the boiler's point of view.

The pump does not have a flow and return - it has an in and out. The
pump will have to be in either the flow from the boiler, or the return
to it (where is dictated by which side of the heating load it is
installed). On the feed side it is installed in the flow, on the other
side it is in the return. Hence *both* sides of the pump are either part
of the flow *or* the return - but not both.

It is far more common to have the pump installed on the flow side before
any valves etc. In this case the flow comes from the boiler into the
pump, and then the flow carries on out of the pump to the heating load.

All a bit metaphysical, I imagined that it is always referenced to the
boiler/combi,

You are right - it is.

not an external pump, but my bro' is always thinking up imaginary problems
and
I can't argue what the correct termnology is by force of logic.

He is working from the assumption the pump has a flow and return - if
you make that mental leap things get confused!

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm" wrote in message
...
andrewpreece wrote:

Flow is out of the boiler and return is back into the boiler. If his
pump is indicating the other way around, then it's back to front


Aah, but flow OUT of the pump ( flow ) is flow INTO the boiler (
return ).

Whoa there! Firstly forget about the pump. Flow and return are terms
relative to the boiler. Hot water comes out of the flow, goes to all the
rads / cylinder(s, and is then piped back to the return of the boiler.

So is the pipe leaving the pump in the direction of flow called FLOW,
because if it's all relative to the pump, then the pipe entering the
pump
must be labelled RETURN, yet it is the same pipe that carries water OUT
of the boiler. Looking at Flow/Return from the pump's point of view (
i.e
flow=out,
return=in ) gives a different labelling of the pipes than looking at it
from the boiler's point of view.

The pump does not have a flow and return - it has an in and out. The
pump will have to be in either the flow from the boiler, or the return
to it (where is dictated by which side of the heating load it is
installed). On the feed side it is installed in the flow, on the other
side it is in the return. Hence *both* sides of the pump are either part
of the flow *or* the return - but not both.

It is far more common to have the pump installed on the flow side before
any valves etc.

It isn't. Most combi's have the pump on the return, as many system boilers.

In this case the flow comes from the boiler into the
pump, and then the flow carries on out of the pump to the heating load.

All a bit metaphysical, I imagined that it is always referenced to the
boiler/combi,

You are right - it is.

not an external pump, but my bro' is always thinking up imaginary
problems
and
I can't argue what the correct termnology is by force of logic.

He is working from the assumption the pump has a flow and return - if
you make that mental leap things get confused!

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Doctor Drivel wrote:

It is far more common to have the pump installed on the flow side before
any valves etc.


It isn't. Most combi's have the pump on the return, as many system boilers.

Why do you bothering to clutter threads with non information like this?

If you bothered to read the OP you would see that we are talking about a
boiler with an external pump - not a combi or a system boiler.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm" wrote in message
...
Doctor Drivel wrote:

It is far more common to have the pump installed on the flow side before
any valves etc.


It isn't. Most combi's have the pump on the return, as many system
boilers.

Why do you bothering to clutter threads with non information like this?

Because what you said was misleading.

Thanks Folks,

Boilers have Flow and Return, pumps have In and Out. That'll do
nicely!

Andy.

In message , andrewpreece
writes

"raden" wrote in message
...
In message , andrewpreece
writes
A question for my brother, who hasn't worked out how to access usegroups.

He has a Worcester Bosch boiler he is about to connect up, but realises
that
he doesn't understand how the 'Flow' and 'Return' pipes are identified.
His sytem has an external pump. He reasons that 'flow' is the pipe
connected
to the output of the pump, and 'Return' is the pipe entering the pump.

I have a combi, where of course the 'Flow' pipe leaves the combi carrying
the
CH water away, and the 'Return' pipe brings the CH water back in to be
warmed
up again.

These two definitions have opposite meanings for the CH pipes at the
boiler/combi.
Which definition is correct for a boiler?

If you think about it, water can only flow one way round the system, it
doesn't matter whether it's through the pump or boiler

Flow is out of the boiler and return is back into the boiler. If his
pump is indicating the other way around, then it's back to front

Aah, but flow OUT of the pump ( flow ) is flow INTO the boiler ( return ).
So is the pipe leaving the pump in the direction of flow called FLOW,
because if it's all relative to the pump, then the pipe entering the pump
must be labelled RETURN, yet it is the same pipe that carries water OUT
of the boiler. Looking at Flow/Return from the pump's point of view ( i.e
flow=out,
return=in ) gives a different labelling of the pipes than looking at it
from the boiler's point of view.

Moist pumps which I have seen just have an arrow pointing in the
direction of flow.

As I said, just take a step back - whether the pump is near the flow or
return , it's still pushing the water into the return so it can flow out
of the return side

--
geoff

raden wrote:
Moist pumps which I have seen just have an arrow pointing in the
direction of flow.

Do the dry ones point the other way?

Rem