Backyard Aquaponics
A place to discuss aquaponics

Thought it was time to add a little plumbing advice to the forum. I, along with others I am sure, suffered from lack of knowledge of plumbing terminology so when at the plumbers shops, it was hard to get across exactly what was needed to do the job you want.

Try and find your local plumbing supplies, sort out what you need (go in at a time when they are quiet) and you'll have a fair chance at getting trade price if you buy it all at once. It certainly doesn't hurt to ask, and if you go to a smaller trade style place, some of them only sell at trade price, and their service is better too. Large stores like the B are generally expensive for pressure pipe fittings.

Just make sure you know exactly what pipe and fittings you need- dwv or pressure. ie sort out your pump to grow beds with elbows, non returns, tee's etc in pressure IMHO is the only way to go. Call it insurance. Also, Barrel unions and stuff like that which you need for easy removal of pumps from the system only come in pressure.

Then grow beds to sump or anything gravity feed, use DWV (hooks up to plug and waste traps). Initially I though 40mm dwv and 40 mm pressure would be the same size but NO, and this can cause all the problems in the world

The confusion can start when you get pressure pipe, say, and dwv fittings. They just don't fit, and never will.
At my local DWV pipe and fittings are a bit cheaper than pressure, which will generally be the case..

IMO, it's not worth stuffing around fabricating fittings to try and save a few quid. Be careful not to mix and match pressure and dwv.

second picture is pressure pipe non return valve, used so that your pump always is primed. Prolongs their life

Third piccy is pressure pipe on the left, dwv on the right, note the size difference (both are called 40mm).

Is non return valve needed if pump is under water?

I thought these were important when pump was above water, so that you don't have to prime them as you say.

What effect would water running the wrong way through a pump have?

For example when the float switches off the water runs back down the pipe and into the pump...

IMO, better to have one with a submersible pump too. Happy to stand corrected, but it's insurance. I think as the cycle stops, the pipes will keep trickling like a syphon esp if grow bed outklets are lower than tank water . The non return valve will stop this syphon effect and create a continuous head for the pump.

Here's a classic example of trying to make things work when you mix up your plumbing types, what might have been one cheap small reducing bush to get from your T piece, onto the valve, has ended up being 3 different types of fittings, mixing DWV, Philmac and standard pressure/irrigation..

pipes are measured either ID or OD -inside diameter or outside.
Depending on whether it is pressure or vent.