I'm a homeowner currently finishing-up a control board for a 4-zone hydronic baseboard retrofit. The system has been designed, and components provided, by a reputable and professional radiant design firm.

The control board piping is really simple and only includes the supply and return manifolds, motorized zone valves and the necessary shut-off and drain valves. Everything is sweated copper connections.

The board is sitting on the bench right now and is not connected to a boiler (leaving that to the professionals), nor any distribution piping. I'm wondering if, when the pros bench-build control boards, they pressure test them before installation in a system?

From my decidedly non-professional perspective, it seems like preparing a board (e.g. capping all the supply & return branches), especially those for large and complex systems would be a real chore. Any enlightenment would be most appreciated.

I'm also a non-pro, but have installed three different systems over the last couple of years and always pressure tested with air before charging with fluid.

It's really up to you as to bench pressure test or not...depends on the schedules you'll need to work around. If you're paying a pro by the hour to plumb your board in to the boiler and he discovers a leak in your work, well, then he'll have to fix it at your expense before he continues.

True, you'll ultimately save time by pressure testing only after all hook ups are made. Quetion is do you pay for corrections with $s or time?

I pressure tested in two phases...one with the PEX hooked up to the manifolds, (and this was where I discovered one of two staples through the PEX in the living room loops...the second one DIDN"T LEAK AIR, but did leak water weeks after being brought up to temperature) and the second with the boiler, circ pump, guages, etc hooked up.

air test it first. The higher the PSI the better. Get some leak detector spray, or soap spray and hit all the connections.

If you use plain spray bottle soap wash it down or you will get green gooey copper in a day or two The detector sprays will not go green. Must be a ph balanced product?

I agree also that some leaks only appear after hot boiler water has run through them for a while. Generally caused by a bad solder joint that had "burnt flux" glueing it together Disassemble that joint and you will see the reason for the delayed leak.

Glycol has a knack for leaking where no other product I know of will. Sometimes years later. Usually these appear at threaded and packing joints.

hr

Bench Test It!! as everyone else has said. It sounds like you have a relatively small system and if you do not already have you could possibly add a ball valve shutoff prior to each of your manifolds. This would allow you to test the remainder.
It is much easier to fix any leaks on the board before it gets installed.... versus after it is all hooked up.

Good Luck....... Alex

Thanks to all for the replies... much appreciated.