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Electrical Tests:
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Check line in for power.
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Check thermal fuse for continuity.
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Check thermostats for continuity.
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Verify audibly that pump runs.
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Verify by touch that boiler gets hot.
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Verify that 3-way solenoid valve works (dumps
water in drip tray at end of shot).
Water Tests:
Water
debit test;
(Goal=65±5
ml water in 20 seconds)
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With a cold machine, test pump
output by checking output volume using the tube that connects the pump &
boiler. It's advisable to buy a two foot piece of tubing to make sure you
don't pump water over the electrics.
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Switch pump on and measure the
quantity of water in 20 seconds (If it's not at least 60ml. the pump is
defective.)
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Reconnect tube between pump &
boiler. Test output volume again, this time at the portafilter (no filter
basket).
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If the test at the pump output
was OK, (and if your machine has one and the 3-way valve tests OK; dumps water
after a shot is pulled), & the test at the portafilter fails there is a problem with the brew
group. It could be calcified or it could have a faulty group valve (if
equipped with one).
Water
pressure test; (Goal=130 psi/9 Bar)
The oscillating pumps in Gaggia home espresso
machines are rated at 14+ bars, and conventional wisdom supposes that espresso
is best extracted at 9 bar (130 PSI). To test
the actual pressure at the group you'll need to either buy a
portafilter
pressure gauge or
assemble one yourself & then
adjust the pressure relief valve (OPV/PRV) until
you achieve 9 bar dynamic pressure in the group.
Brewing water
temperature test; (Goal=200±5 °F)
Is the boiler getting the water hot enough? Find out using
Styrofoam cup
method. Or, if you need
to be super accurate & do this for a living there's the
Scace
Device.
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