OK, please be patient, I'm a little woozy from some surgical shenannigans last week, but thought that I could usefully spend this recovery time fussing with my espresso setup which is currently as follows:

An original Isomac Ritual with the dual boiler/brew pressure gauge, which is using an Ulka Vibe pump with a Chris's Coffee plumb-in conversion kit, and is being fed from a 5 gallon water jug via a Flojet integrated pump system.

I also have an Italian-made 110V rotary pump and motor assembly sitting here on the bench which is just begging to be patched in to replace the Ulka pump.

The rotary pump appears to use pretty standard 3/8" compression fittings, so I hung some 42" braided hose off the pump, dropped the input into the water bottle, and when I applied 110V to the pump was rewarded with a pretty spectacular spray of pressurised water from the output tube.

So far, so good, it looks like the rotary pump could be externally mounted and take its input directly from a 5 gallon water jug, its output could be plumbed to where the Ulka pump is currently feeding, and its electrical control 'stolen' directly from the wires to the Ulka pump.

I pulled all of the sheet metal off of the Isomac and located the Ulka pump, which is being fed by some 1/8" low-pressure tubing with a John Guest press-on fitting, and what appears to be an electronic anti-syphon valve - I am assuming that all of this section is part of the Chris's Coffee plumb-in conversion. The output from the Ulka pump looks to be 1/4" compression which feeds a short 6" high pressure hose covered with metal braid. Unfortunately, a standard 1/4" compression fitting doesn't fit on to the boiler end, and appears to be both oversized and the wrong shape.

Now, here are the questions:

1) Does anyone know what type of fitting the Isomac uses between the Ulka pump and the Boiler? My hunch is that it will be metric, and I'll need to either be creative or start tearing my hair out.

2) What would be the best way to convert from the Rotary pump's 3/8" output to the Isomac's boiler input?

3) Before I start tearing hoses apart, does either Chris's or EPNW have stock on the original hose - so I can easily switch back if I pooch the conversion, or be able to restore the machine's original configuration when it's time to sell?

4) Assuming that I can solve the hose conversion issue, I'm also wondering if the stock Isomac-provided control relay would be capable of handling the increased load of the external pump, or should I use an external 110V relay switched by the Isomac's control unit?

5) If a relay is a good idea, does anyone have a recommended part? I don't think that there's an operational need to use an SSR unit, but that a quality 15amp, fast-acting, double-pole, single-throw relay should do the trick - but am open to all opinions.

6) Finally, I have beat the pooh out of Google trying to find any web pages covering this sort of conversion, but haven't been able to find anything substantive - any useful URL's would be gratefully received.

Cheers - wishing you all a Merry CMOS and a Joystick Novell

Dr Jim

Hi,

While I don't have the information on this exact machine, I can give you some general knowledge. Most European machines don't, oddly enough, use metric threads, but BSPP (British Standard Parallel Pipe), probably for the same reason the old Morris Minor had its distributor coming out the bottom of the block, which is: nobody knows. At any event, McMaster-Carr has some stainless NPT-to-BSPP adapters from the Parker instrumentation catalog, which is what I used when I plumbed in my Techno. The pumps seem to use something called a 3/8" gas fitting, for what that's worth.

Best,
David

David -

You were spot on - if anyone else ends up in the same situation, the Isomac uses a male fitting with 1/4" BSPP (British Standard Pipe Parallel) threads on the manifold which the Ulka pump feeds.

Fine, a short trip to the helpful folks at 'Fittings Inc' here in Seattle and we now have the correct bits to adapt from 3/8" NSP (National Standard Pipe) to 1/4" BSPP - which I believe is all of the plumbing adaptation I'll need.

Still unanswered is the question of whether or not the Crouzet relay number 84137011 on the Isomac will be able to source enough power to run the pump - according to Chris's Coffee pages, this relay is rated at 25 amps, which I will assume should be sufficient to run the following motor:

"Ulka tipo 128P" rated 110v 180 watt...

But I am guessing about this.

Cheers

Jim

Dr Jim wrote:...according to Chris's Coffee pages, this relay is rated at 25 amps, which I will assume should be sufficient to run the following motor:

"Ulka tipo 128P" rated 110v 180 watt...

amps = Watts/volts; the switch is more than sufficient.

Indeed the Crouzet relay was more than ample for the task - I was concerned that the traditional V/O/Watt calculations might not have correctly predicted the sort of reactive inrush current which the startup capacitor looked like it might require - but I think I was over-engineering in my brain, narcotics will often have that effect, even when legal...

Lessons learned:

1) If there is a way to pooh up perfectly good plumbing, trust the British to find it - mutter, mutter, mutter - I now have a potentially useful assortment of BSPP and BSPT fittings tucked away for future use.

2) When dealing with vane-pressure pumps always pre-prime and run until they drool all over the counter BEFORE hooking them up to an unreachable fitting, your knuckles will like you much more afterwards.

3) The pressure profile on a vane pump is vastly different and apparently more stable than a vibe pump - it will also be even more unforgiving of stupid tamping/packing errors.

4) However, a properly prepared shot seems to have more OoompH! bite, clarity, and even crema than I was getting with the vibe setup that was in there.

So, considering that I'm into this entire conversion less than $75, it seems like a worthwhile undertaking - the noise level has dropped, and I believe that my poor abused Rituale is now capable of producing better shots.

The next phase will be to replace the CEME pressurestat with some form of solid state temperature controller.

Cheers

Jim