ACS Minima pump constantly on after powering on

CyB0rgg

@DavecUK I need your expertise, oh mighty one.

Was working happily for 4+ years but yesterday the tragedy struck ;)

My wife reported that machine (that we leave on for the whole day with just the brew boiler on) have started pumping water as it does from time to time. This time however it did not stop, was just going and going.

It wasn’t until I smelled something acrid from upstairs and ran downstairs to see what happened, when I have realised that something was amiss.

I have initially thought that the pump burned as it was going for a good 10 minutes, but after the cooldown period it seems to be working.

When I turn the machine on, it starts instantly pumping water and it overflows immediately via the silicon tube back into the water tank. I assume that most likely the water level sensor in one of the boilers have malfuctioned and that’s why it keeps pumping the water. I have also assumed (by the method of elimination) that the water level sensors are the super-thin wired ones in the brass nut on top of the boiler. They both have resistance of around 56kOhms and that does not change when the pump is running.

With no schematics for the machine I am not sure what to do next, so any pointers would be appreciated.

As I last resort I would be willing to ship the machine for the repair, but not sure who repairs them in UK ?

Thanks !

DavecUK

CyB0rgg I have initially thought that the pump burned as it was going for a good 10 minutes, but after the cooldown period it seems to be working.

When I turn the machine on, it starts instantly pumping water and it overflows immediately via the silicon tube back into the water tank. I assume that most likely the water level sensor in one of the boilers have malfuctioned and that’s why it keeps pumping the water. I have also assumed (by the method of elimination) that the water level sensors are the super-thin wired ones in the brass nut on top of the boiler. They both have resistance of around 56kOhms and that does not change when the pump is running.

The pump can only run for 2 or 3 minutes then a safety system kicks in and stops the pump….to save it.

The super thin brass things with thin wires are the temperature sensor. and you should not try and measure their resistance…in fact it’s best to leave the wires to them alone, unless you want to buy new temp sensors.

Temp sensor = red arrow Level Probe = Green arrow

Check the wire to the level probe is attached and not loose. Follow the wire back to the black box (Gicar Box), check it’s connected and check for a black grounding wire from the Gicar box, Check it’s grounded to the frame and not loose, on early machines it was grounded to the boiler, if it is, move it to ground on the frame.

If all the wiring looks fine, it might be the level probe has scaled up…but that depends on the water you use?

CyB0rgg

Many thanks for the swift reply - my bad, I have assumed that there will be 2 water level sensors.

The ground wire from the gicar box indeed goes back to the top of the brew boiler but it is a solid connection to the ground so that’s not it.

After taking the gicar box out and trying to turn on the machine I have noticed the same smell again - this time pinpointed to the gicar box, so I guess I have found the problem ..

Is there anywhere I can get them in the Old Blighty ?

P.S. The machine has never seen the tap water, it was always bottled (initially) and then double RO.

Do you know what should be the reading on the sensor when the boiler is full ? Is that simple rod that touches the top of the water when the boiler is full or something more sophisticated ?

Thanks !

DavecUK

CyB0rgg The ground wire from the gicar box indeed goes back to the top of the brew boiler but it is a solid connection to the ground so that’s not it.

Ideally, it should be earthed on the frame

CyB0rgg After taking the gicar box out and trying to turn on the machine I have noticed the same smell again - this time pinpointed to the gicar box, so I guess I have found the problem ..

Undoubtedly, sounds like it may have burned out.

CyB0rgg Do you know what should be the reading on the sensor when the boiler is full ? Is that simple rod that touches the top of the water when the boiler is full or something more sophisticated ?

No, it’s exactly as you say, when the tip of that rod is earthed by the water, the pump stops and the heating elements come on. Are you in the UK or US?

Regardless you need to get the right Gicar box from ACS, because they are programmed with custom firmware and are made by Gicar for ACS. They are not cheap, but shouldn’t be too bad for replacement cost.

CyB0rgg

I am based in U.K., I saw the part on a couple of us websites but nothing in U.K. how do I contact ACS ?

Thanks

DavecUK

CyB0rgg Maria at sales@mevsrl.net