Binder Test Points, Ball filters and other plumbing mysteries

[Chris George]

Dear All I am installing a heat pump and have had a group of engineers to design the installation. Inter alia I have been asked to install a "Binder Test Point" either side of the two pumps between the pump and their associated Isolation valves. Addtionally, the HP supplier has asked to install a Filter Ball on the low pressure side (whatever he meant by that) quoting =A3160 and a Filter Ball (Copper) on the other side at respective prices of =A3160 and =A380. On the basis that his prices were 3x more for most other items I suspect the true cost is circa =A350 and =A330 odd! Trouble is I have not the faintest idea what he meant by these terms and Gooling them does not help. Any ideas? Chris

[Aidan]

Binder test points are an industry standard pressue test-point device. It has a neoprene/rubber plug in a brass housing. The rubber plug has a hole through it, but the housing compresses the plug so water can't leak out. You can shove a test probe through the hole, usually to measure pressure, sometimes temperature. They're very useful for diagnosing faults with plant. They're usually found in pairs on commissioning valves or orifice plates, where they're used to measure differential pressure and flow rates. Like this;

the one place where you shouldn't install them is near pumps; confidence goes pop. The local turbulence causes a temporary loss of pressure; the pressure recovers downstream. You need 10 x straight pipe diameters downstream of a pump (e.g.,

15mm pipe =3D 150mm), 5x diameters downstream of any other fitting. Trying to diagnose pump faults with the pump curve and with binder points installed adjacent to the pumps suggests technical naivety.

Filter ball, dunno, better ask him. You can get ball valves with a filter in the bore of the valve. I think that's what he meant; a strainer on the pump inlet (low pressure) would stop entrained particles & prevent them damaging the pump. You'd be better off with a standard Y-pattern strainer with separate full-bore ball valves to isolate for draining. If that is what he meant, =A3160 or =A380 is taking the Michael in a big way.