I have been slowly but surely refurbishing a GB5. I am very close to finishing but have run into a challenge I believe is off my knowledge....here is what's up...machine gets to proper temperature and all lights come up...however when you press the brew button, pump motor does not kick in.

I check voltage and realized fuses were blown away, replaced fuses and as soon as the machine turns on again one of the fuses blows up...sometime it happens it blows up after I enhance the brew button. The fuse that blows up is the one that comes from the same terminal to which the yellow wire from pump motor goes to.

Could it be the pump motor itself that is shorted and creating the trouble? Any way to diagnose the motor before I go buy a new motor and realize that is not the problem?

Thanks in advance for any suggestions

Ricardo

I have only seen GB5's so, naturally, I defer to the GB5 pros wherever they may be.

Do you have the machine plumbed in? If so, you can always operate the machine functionally with reasonable line pressure and the pump electrically disconnected.

Why not simply electrically disconnect the pump and see what happens?

Next step would be to get some equivalent adaptors from your local Radio Shack or electronics supply house and rig up a 220-240 vac light bulb to the wiring from the machine. Sourcing a 220-240 vac bulb could be a little challenging.

Although I don't know much about this topic, I hope you get your GB/5 up and running soon.. beautiful machine both stylistically and functionally.

Good luck!

Without the pump motor Eric I am only getting a water pressure of 3 bars from the water line, which I doubt is adequate for brewing espresso.

It is not (obviously) adequate for proper espresso but it would test all of the other machine functions especially if this is an AV model.

Certainly Eric and so far everything seems okay...well besides the flowmeter...it gives me a flowmeter alarm but can still brew continuously. Other than that, all lights come up and the both boilers reach proper temperature, pressure stat works, probes work...the pump motor or somehow voltage to it seems to be the problem... Would a short in the motor cause the fuses to blow up? I disengange the pump from motor to see if it was a pump issue but the shaft is doesn't move even without pump...but again how would it move if it has no voltage to it as the fuses blow up right after I replace them! Am going in circles at this point

Would a short in the motor cause the fuses to blow up?

Yes, but that is likely not your problem. The motor shaft should spin freely. If it does not, then you are drawing what's called LRA (locked rotor amperes) for enough time to easily blow the fuse(s).

I would remove the motor and have it checked at a motor repair shop. As necessary, they can EASILY replace the bearings as that APPEARS to be the fault. They would also run a check on the motor and compare to the nameplate data.

As per a friend suggestion, I disconnected the motor from the wire that comes from the machine to see a couple things:

1) was I getting 220v at the end of the wires? Yes, 210v was measured at the end of the wires thus voltage is there to energize the motor.

2) did the fuses blow up after engaging the brew button? No, without the motor attached to it, fuses didn't get blow up.

The motor does have continuity though and the shaft does move with my fingers...not sure how freely it should move but let's say that it keeps on moving for merely a second after I give it a spin with a flat screwdriver.

Am attaching an image of the motor plate. Perhaps is not the right motor?

You should be able to EASILY spin the motor with your finger tips and it should continue to spin for several seconds.

This is a replacement motor but does appear up to the task (if all was well with it). My previous recommendation still applies. You could also "plug" the motor into a 220-240 vac source but the problem I see with that is the typical outlet for that is protected with a higher amperage breaker than the fuses in your machine.

Yes, I believe the motor is the problem but a "motor shop" would still be your best bet dollar wise.