On Jan 29, 1:49*pm, "Dave Liquorice"
wrote:
Domestic CH circulator type pumps. The graphs giving flow rate use
"head" as the other axis. What head is this? Highest to lowest point
in the loop? Pump to lowest, pump to highest? Something completely
differnt like flow resistance of the entire loop?

I'd like to have a rough guesstimate as to the flow rate the load
controller on the woodburner is producing so I can get an idea of how
much energy is being transfered from the woodburners boiler to the
thermal store.

--
Cheers
Dave.

The head of a pump is the maximum pressure it can generate.
Usually expressed in feet or meters.
One foot head + 0.4336 psi.

The flow rate is the maximum flow it can put through.
Usuallty in gallons per minute or liters per second.

However, it can't do both at the same time, these are the limits of
it's performance, the two ends of the graph. In practice,you wouldn't
run it close to either end.

So, It can do max flow at zero pressure and max.pressure at zero
flow..

So, for practical purposes, it operates at less then maximum of
either.

There is a performance graph, the figures just outline the extreme
parameters on the graph.

So if you had a pump that was say 10m head and 20 litre/second it
would probably move about 10 liters.sec at 5m head.

This not exact because the performance curve is non-linear, you need
to look at the manufacturers graph.