I bought an Isomac Tea used about two months ago from a local buyer. and have been using it for maybe 2-4 shots of espresso/cappuccinos every day ever since. A few days ago, upon turning the machine on, I noticed that it took longer than normal to heat up. As I had some time, I just waited another hour and then pulled my normal drinks.

But the next day, on turning the machine on, it didn't even get up to pressure or temperature. When I turn on the switch, the pump never engages (it usually goes on for 3 seconds or so right after I switch it on, then quiets down). The boiler pressure gauge never moves from it's 0 position, and the grouphead never gets hot. Neither the steam wand nor the hot water wand shoot out any water.

I'm not sure what could be going wrong---according to the previous owner, the machine was services by Chris' Coffee about 6 months ago, including descaling. I haven't descaled it myself since then. I figured I might as well take some pictures of the internals, so below are three pics:





Any help is greatly appreciated!

cheers,
leo

Do the lights come on? If you turn it on and raise the brew lever does the pump come on and pump water out the group? Could be dozens of things.

lfranchi wrote:When I turn on the switch, the pump never engages (it usually goes on for 3 seconds or so right after I switch it on, then quiets down). The boiler pressure gauge never moves from it's 0 position, and the grouphead never gets hot. Neither the steam wand nor the hot water wand shoot out any water.

First check for a sticky vacuum breaker valve failing to prevent false pressure. Does the heating element turn on once you open the steam wand valve? As Dave noted, if that's not it, then there are other less obvious possibilities (e.g., scale on water level sensor leading to boiler overfill), but let's start with the easiest answer.

The lights go on as normal when I turn the machine on. Moving the lever up into the brew position engages the pump, and cold water comes through the grouphead.

I don't think there's any false pressure, cracking open the steam wand doesn't release anything. Keeping the steam wand open and waiting, I can't notice any heat being generated at all.

Hmm, ok. I need to borrow a meter from a friend and see what the voltages are later today then.

cheers,
leo

So it's been a long time since I touched a voltmeter. But I think I did it correctly... i set the meter on 110V DC and touched each lead to the heating element leads (they come right out of the side of the boiler, yes?)

Anyway, the voltmeter didn't budge. So replacing the thermal fuse would be a good thing to try?

cheers,
leo

edit: fixed typo

I will assume that you meant that you set the voltmeter to "110" and not "10" volts....

So voltage is not getting to the heating element. Next step is to check the pressurestat. (the following is a generic description- your machine may vary):
The pressurestat is the control that switches the electricity to the heating element. If you trace the heating element wires back away from the heating element connections they should lead to the pressurestat. There will bet two "sets" of wires-
- Two from the heating element. These may have another pair connected that illuminate a lamp on the machine's face panel.
- Two that supply power to the pressurestat. These would be the next two to test to see if they are getting power to the pressure stat.
- There may be a ground wire as well.

If you have checked the thermal protection device (thermal fuse or resettable safety thermostat) and that is good, then:

- If power IS getting to the pressurestat, then either the pressurestat is not sensing pressure (or lack thereof) in the boiler correctly (scale or bad diaphragm or such), or the contacts in the pressurestat are bad or dirty.

If power is NOT getting to the pressurestat then the power switch may be bad.

Again, these are generic tests that generally apply to machines with a pressurestat. Yours may vary. These people are professionals. Don't get all deaded up from electricity. If you are not sure, have someone who is familiar with such tests perform them.

How do I go about checking the thermal fuse? From Eric's post, I understand where it is, but I'm not sure how to test it.

And then, to test if power is getting to the pressurestat, I should check the voltage on the wires that go from the pressurestat to the power relay?

cheers,
leo