Izzo Alex Duetto - Plumbed in yet my water tank fills with water?

When you check your plumbed in Espresso machines water tank, it always has some water in it.

Find and bookmark our home page at http://www.coffeetimeuk.com/

Also see:

Many people by now will have plumbed in a Duetto and either have kept some water in the tank, or a weight to ensure the pressure switch is held in the closed position and the machine can operate. Imagine their suprise when they check the tank after some days or weeks to find some water in it. If they have a weight in the tank and don't check it for 2-3 months they are likely to end up with a puddle of water under the machine.

As the Izzo Alex Duetto has been around for a few months in Europe not and around 3-4 weeks in the US….I thought it's time to write this article.

First…there is nothing wrong and if this water didn't appear in the tank, the brew boiler (used for making coffee) would rupture….let me explain.

The brew boiler is about 0.8 litres, plus another 80 cc for pipes etc.., when the water in this circuit is heated to brew temperature it expands by about 4%…this is around 30cc of extra liquid volume. This has to go somewhere, because water cannot be compressed, so it vents out of the OPV, one of the reasons this OPV is there. If it didn't vent out of the OPV the pressures generated would be so great they would easily rupture the brew boiler/filttings!

So if you ever have a faulty OPV and decide to dispense with it by capping the connection off……..dont'!

The OPV of course vents back into the water tank….and this expansion happens each time the machine is switched on. So if you switch it on once per day that's approx 30-35 cc per day or 210cc in a week. So if you are plumbed in and using a weight to keep the machine switched on, you should check you cold tank and empty it once per month (more often if you don't want it to go mouldy).

Note: This will happen with any Espresso Machine with a rotary pump that vents back into the tank. Although this OPV is not used for pressure regulation under normal circumstances, it does deal with expansion of water from within the sealed brew circuit of signgle Boiler non HX, HX and Dual Boiler Machines.

P.S. If like me you are lazy and prefer to do it once per month, simply break 1/4 of a Milton tablet off and place it in the tank before you put the tank back, this will keep it mould free.

To see who wrote this page….please click the "HISTORY" tab shown on the lower part of the screen.