"Andy Hall" wrote in message
news
On 25 Oct 2003 10:54:56 -0700, (Danny)
wrote:

one problem after another! Now I'm back to my orginal problem, CH
valve shuts off, boiler cuts out! Interestingly enough though, when I
fully open the gate valve into the HW storage tank, turning the pump
on full speed, you can hear water rushing through, air being expelled,
and then gushing water into the FE tank? I've heard about
over-pumping (?) but why would this cause water to be expelled though
the FE tank this way?
I would have thought that considering the pump
is sited after the pipe work leading to the FE tank (ie water is being
sucked rather than pumped) that the water would only flow up this pipe
if there were a blockage?


If the feed pipe and the vent pipe are on opposite sides of the pump,
pumping over or sucking down of air will tend to occur depending on
which way round they are. This would in any case be a fault in the
design.

However, you can get the same effect if they are both on one side but
that there is a pressure differential between them - it doesn't have
to be very much.
This can happen if they are connected to points on the circuit that
are too far apart or if there is a flow restriction. Winding up
the pump speed will exacerbate this.

Based on what you've found at the bypass, I suspect that other parts
of the system are full of sludge as well......

I would suggest you drain the system and if you can undo a fitting
near the points that the feed and vent pipes join the system see if
there is more sludge, or take a look at a nearby radiator.

I'd be willing to bet that there is a lot of grot in the system.




.andy



Or it could be a leak from the coil in the HW tank.


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