Rotary pump conversion - how to bypass water tank cutoff?

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
daviddecristoforo

#1: Post by daviddecristoforo »

My trusty 20 year old LaScala Butterfly has finally decided to retire. To replace it, I have settled on a one year old Rocket Appartamento which I got for a very attractive price. I plan to swap out several of the parts from the old machine, flow control, joystick wands, etc.

Many years ago the Butterfly was converted to a rotary pump. I am considering doing the same thing to the Rocket. Forgoing the "why would ja" question and just going with "because I want to", here's the question.

The Rocket has a sensor that shuts the machine down if the water tank gets too low. Since the tank would not exist with the rotary pump setup, how would one go about defeating that function?

Nunas
Supporter ♡

#2: Post by Nunas »

I've seen two types of water reservoir sensors, magnetic and gravity. The magnetic sensors have a little magnetic float that triggers a switch. When the reservoir is low, the magnet is in the proximity of a magnetic switch on the machine's body. The gravitational sensors have a switch and a spring. When the reservoir is empty, the spring lifts the reservoir off the switch. In either case, it should be a simple matter of finding that switch, determining if it is normally open or normally closed with a full reservoir. If it is NC, then jumper the two contacts on the switch. If it is NO, then just remove a connection from the switch.

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JRising

#3: Post by JRising »

An appartamento's reservoir sensor is conductivity based. Just plug the sensor's wire onto a ground terminal instead of the receiver cup (white cup under reservoir). The Rocket machine's already have that huge stack of grounding terminals on the floor waiting to be used, use it and if you ever need to reverse the change, it's easy.

While modifying and maybe improving an appartamento, be sure to consider adding an SSR or a sacrificial relay for the p-stat/heating element circuit, so that the machine isn't burning its own powerboard's relay nor the p-stat.

daviddecristoforo (original poster)

#4: Post by daviddecristoforo (original poster) »

JRising wrote:...be sure to consider adding an SSR or a sacrificial relay for the p-stat/heating element circuit, so that the machine isn't burning its own powerboard's relay nor the p-stat.
That sounds scary! Could you possibly expand on this? I'm not at all sure I'm going to do this and I really don't want to bugger up the machine! My main reason would be so that I can direct plumb it and not have to bother with refilling the tank all the time. That was the main advantage with the conversion on the Butterfly.

PS since the vibe pump is 110, I should be able to power the rotary pump motor with the same leads, no?

NicoNYC

#5: Post by NicoNYC »

daviddecristoforo wrote:PS since the vibe pump is 110, I should be able to power the rotary pump motor with the same leads, no?
I wouldn't assume as much. The usual ulka vibe pumps draw 40-50W, vs a 1/4 HP motor for a rotary pump which draws about 200W. You can check the motor in your LaScala but I expect it to be in that ballpark. You run the risk of burning out a relay on the control board in your new machine.

EDIT: I found an image of the control board for an Appartmento, it looks like R2 (the pump relay) is rated for 5A, which should be ok for a rotary pump. but double check your control board and pump, don't rely on my numbers.
https://www.chriscoffee.com/products/ro ... 0v-3rd-gen

JRising

#6: Post by JRising »

daviddecristoforo wrote:That sounds scary! Could you possibly expand on this? I'm not at all sure I'm going to do this and I really don't want to bugger up the machine! My main reason would be so that I can direct plumb it and not have to bother with refilling the tank all the time. That was the main advantage with the conversion on the Butterfly.
PS since the vibe pump is 110, I should be able to power the rotary pump motor with the same leads, no?
Take a look at the wiring of the machine. Appartamentos come in two different wiring plans for the element circuit. Either with the Board reading the p-stat signal (2 p-stat wires, both connected to the Box) or with the Board supplying power through the P-Stat. The second, obviously, being the better of the two. Both being okay for a machine that is used on Sunday afternoon once a month to brew 2 or three espressos. But if the machine isn't going to be used like a real machine, there'd be no sense in installing a rotary pump.

There are plenty of threads in this forum that elaborate on the Appartamento's wiring issue. Rocket "Fixed" it by going from wiring plan 1 to wiring plan 2, but if you're going to fix it because it's your machine and you care, do better than Rocket's "Oh, it's not an R58, it's not meant to do more than a few espressos a month" attempt.

The pressostat topic got several responses in this thread:
Rocket Appartamento over pressure/loud squealing?

As for installing an SSR, you can actually drill holes in the metal pole that holds the receiver's breather tube, then the pole is a heat-sink for the relay and the reservoir carier can be removed without having to take the relay off of its mounting location. Have the p-stat operating the SSR instead of the board or element, and the SSR powering the element, right?

daviddecristoforo (original poster)

#7: Post by daviddecristoforo (original poster) »

When I converted the Butterfly I ran the pump wires to a relay. The motor was connected to the other side of the relay and drew power from the main 110 plug. It sounds like this would be the safest way to go. Then I would only have to defeat the low water level circuit. I'm not going to do this unless I'm confident that I'm not going to bugger the machine! Unless someone can provide me with a diagram of how to do it differently. I'll post some pictures of the insides as soon as I can.
Thanx for all the advice!