QUESTION
When we open our cottage in the spring, the first thing on the agenda is to reconnect and start up the water-supply system from the lake. Last year when we did this, we tightened all connections to avoid air leaks and primed the system, but on starting the pump we could not get any pressure. The system is a two-pipe variety with a venturi unit connected to the incoming pipe from the lake. By process of elimination, we established that the venturi was the problem. Upon dismantling it, we discovered the unit was heavily corroded. What is the easiest way to remove all the rust?

ANSWER

First of all, excellent detective work in identifying the venturi as the problem, says Brad Hallam, manager of The Pump House in Richmond Hill, Ont., which sells and services every kind of cottage pump imaginable. Most cottagers faced with the same dilemma mistakenly replace the pressure switch and their problem persists.

Unfortunately, knowing where the problem is and fixing it are two different things. First, let’s explain how a venturi unit works. It’s a conical-shaped metal or, more often, plastic piece with a nozzle at the smaller end, hidden inside the injector. When water travels through the nozzle, it increases in speed; then, when it hits the venturi, it is slowed down, which creates pressure.

That your venturi is corroded isn’t a big deal. Because they sit in water, they’re almost always corroded, says Hallam. The problem is likely that the nozzle at the small end is clogged. You could try using a coat hanger to clean it out, but that won’t prevent more gunk from coming through. What you really need to do is disassemble the injector itself to get at the nozzle. If you have any difficulty getting the pipe fittings to come off, Hallam recommends soaking the whole unit in CLR. (Just be sure to give it a good rinse before reusing.) Once you get at the nozzle, he says, it should unthread easily and can be cleaned out. If your nozzle is metal, you could also use a propane torch to heat the fittings until they come loose, says Norman MacKenzie at Norm’s Pumps in Marten River, Ont. And if all that seems like too much trouble and everyone is clamouring for water, you can buy a whole new injector unit for less than $100. (When you have time, keep working on the old one and hold on to it as a spare.)

Christine Langlois

* Published in the April 2008 issue of Cottage Life