(First a story, mainly ranting and letting off steam, then there's a
question at the end)

Just bought a pair of Pump Ball Valves (screwfix id 13885) and a Pegler
Terrier Circulating Pump - TC5 (screwfix id 67174) to replace an ageing
and
noisy central heating pump. Didn't intend to use the Ball Valves - rather
hoping to re-use the originals, and isolate the pump with those for a 10
minute replacement job, bought them simply to bugger up Murphy's law and
use
as back-up, well, they were cheap.

Four Hours; Four Sodding Hours. That's how long to try to remove old pump,
go out to B&Q with nut off new valve to get big-chuffing-spanner, then to
Wickes, then Machine Mart, then finally to a pretty testosterone-pumping
real tool shop. All to no avail, cannot get anything of fixed size to fit
the 40-something mm across-flats nut on the ball valve. Did get an
eye-catching 32mm open ended spanner (that's good for the 22mm side of the
valve, also, causes any number of yobs on street corner to pass on to the
other side of the road - hey, it's a Big Spanner), and a rather more
robust
adjustable wrench for the Big Nut. "Job's a good-un", I thought.

Thirty minutes later, with the best (and newest) tools to hand, could I
shift the Big Nuts on the original Ball Valves attached to pipework and
original pump?, could I buggery. We're talking
full-arm-shaking-pipe-rattling force here, of a 30-something 6 foot male.
Could remove the compression fittings onto the 22mm pipework (Big Spanner
to
the rescue), but no play in pipework to allow the pipes to be removed from
Ball Valves, and still no hope in hell of removing the Big Nuts from the
Ball Valves to slip the old pump out (previous problem with a leak from a
3-port-valve did, I think, cause a lot of the problems resulting in
corrosion between Ball Valve and Big Nut).

Finally, undid both compression nuts (top and bottom Ball Valve - pump's
aligned vertically) and hack-sawed through one of the compression fittings
to allow all components to slide off the existing, non-moveable pipework.

That's when the real fun started...

Having now had to drain the system to get the original ball valves off the
pipework / pump, and replaced with the screwfix ones I try to mate the
pump,
and tighten Big Nuts. Nuts (or ********, if you prefer) - would they
thread
onto the pump?, have a guess. Had to remove one of the Ball Valves to
prove
to myself that the threads were compatible - they were. The problem seems
to
be that the Big Nut will only sit properly, and flush, once it is fully
in
place past the valve actuator on the Ball-Valve, that is, in its final
position. Problem - if there's (for example) a pump already in place
between
two of these Ball Valves, tight fit and all with non-malleable pipework,
then you cannot easily (more later) offer the Big Nut upto the thread on
the
pump housing without risking cross-threading the nut.

Looking at the mangled remains of the old pump it appears the original
installation suffered much of the same problems (with apparent
cross-threading on one of the Ball Valves).

Examining the Ball Valves (I did a lot of this between cursing and
screaming) its quite obvious that there is a design flaw that prevents the
nut seating properly unless it can move freely to the end of its travel,
something not possible with a pump / thread in its way. In the end, I had
to
resort to a combination of straining the pipework (bound to fail, now,
expecting leaks by the morning) and forcing the nut onto the thread of the
pump using a strong pair of hefty pliars. In the end, a 10 minute job took
me 4 hrs.

SO

The question is... for someone with experience of plumbing and central
heating... Just what is the trick of the trade to mating the Ball Valves
to
the pump bodies?, I imagine with play in the pipework it would be fairly
straight-forward, but for existing installations, with no such play, how
do
the Pro's handle this?



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