I'm working on other issues with my espresso machine and tested the flow rate of my ULKA EX5 pump today through the grouphead (no showerscreen and jet breaker) and open steam wand. I got 580ml/min and read somewhere that i should be expecting 660ml/min. Also, I read, they loose flow rate over time. So the question I have for you is after how much flow rate loss should I be changing my pump? Do I need to change it or would a rebuild help? Thanks!

Hello:

bengee wrote: ... tested the flow rate of my ULKA EX5 pump ...
... should be expecting 660ml/min.
... Do I need to change it or would a rebuild help?

It all depends. In any case you are not too far from your expected flow rate.
Look for a flow/pressure graph for the EX5 and check that info. Besides that, what you suppose is zero pressure is not really zero pressure.
To measure flow at zero pressure you have to measure it at the pump's exit and not after it has pumped water through your espresso rig's innards.

Your pump is probably OK.

BTW: you don't rebuild Ulkas as there are no available replacement parts for them.
If you lose anyone of the thinguies inside it when taking it apart, you can try to get an old one (burned coil) and salvage the parts.
The only possibility I know of.

Check this site out, it explains everything you need to know about cleaning an Ulka pump.
The only thing is to be very careful lest a thinguie fly off the table and hide somewhere forever.

http://ulkapumprepair.blogspot.com.ar/2 ... -page.html

A search on HB, Google et al will get you a wealth of information regarding Ulka repair/take apart/ etc.

Cheers,

CIV

civ wrote:In any case you are not too far from your expected flow rate.

Your pump is probably OK.

CIV

I'll focus on this part of your answer! Thanks for all the great info.