PID & Cooling Flushes

Kelsey

Read an interesting post over on Home Barista about the BZ07 and its odd behaviour around flushes:

http://www.home-barista.com/espresso-machines/temperature-measurement-bezzera-bz07-pid-t16214.html

One of the things I'd said in chat was that for whatever reason, the BZ07, unlike the BZ99, didn't seem to need a cooling flush before a shot.

I'd assumed that was the PID doing its job, but the guys over at HB have done some interesting tests - according to the OP, flushes wind up *warming* the system rather than cooling it.

That seems fairly consistent with my own experience too.

On another note, I wonder if it's possible to install the dual temp gauge as the current boiler pressure isn't massively useful.

Lacehim

on 1341117524:

Read an interesting post over on Home Barista about the BZ07 and its odd behaviour around flushes: http://www.home-barista.com/espresso-machines/temperature-measurement-bezzera-bz07-pid-t16214.html One of the things I'd said in chat was that for whatever reason, the BZ07, unlike the BZ99, didn't seem to need a cooling flush before a shot. I'd assumed that was the PID doing its job, but the guys over at HB have done some interesting tests - according to the OP, flushes wind up *warming* the system rather than cooling it.

Cooling flushes are usually used for machines that when idle overheat the water in the HX tube, so the first time you brew water it's super heated.  If you don't need a cooling flush count yourself lucky!

on 1341117524:

On another note, I wonder if it's possible to install the dual temp gauge as the current boiler pressure isn't massively useful.

I might be wrong but you usually need a flowmeter, so you can't just slap a new gauge in, it requires more plumbing and a flowmeter to work.  I wouldn't bother, just be happy the way it is!

Kelsey

Thanks Lacehim, that's what I thought - on both counts. I'm assuming the connections for the gauge plumbing are in place, just not sure what's involved. It actually feels like a much smoother process using the 07 than the 99.

Brett H

Could you install an e61 temp gauge in the top of the group head and get a second dual gauge to report on oPV settings as well as your current boiler pressure?  :stir OR Shot answer: buy a second machine and mod away. Long slightly medicated answer: Just enjoy your fabulous new toy and use ya taste buds as a guide!  :thumb: Don't fall into the trap of modding a machine before you've lived with it for a while.  I had the Unico Splendor which was great but then after a number of years I wanted to mod it to make the temperature changeable.  I completed this mod by phoning Attilio and purchasing a machine that was intended for this purpose.  He was thrilled to sell it to me I'm sure safe in the knowledge that my sphere of palatal experience only extended to green apples and not green apples; but, nonetheless I now have a machine that I don't want to mod myself.  Why not you all ask.. It'd be bitchin' And awesome if a musician redesigned an espresso machine :thumb:  Alas despite being very confident with brick saws up ladders and angle grinders with no guards to cut extra deep I'll leave those mods to the guys who do it for a living. Don't get me wrong, modding is fun and awesome if it's done within safe parameters but it's not fun when your primary method of coffee deliver is 'out of action' and 'experimental'!!!  We pay big money so that we have better than cafe coffee how we want it, when we want it.  Don't kill the rainforest by jeopardizing that precious luxury! EDIT:  Lacheim said it best, "just be happy the way it is."

beanflying

Warming flushes needed on the Izzo if I am using it outside with a cool breeze blowing over the group after an idle period. On a reasonable day or indoors it otherwise sits nice and stably. PID won't help or hinder the need for a flush either way either as it is just keeping the boiler within closer tolerances and apart from that has no effect on the group that a P/Stat wouldn't have. Needing a heating or cooling flush has to do with mechanical design of the group/hx distance to boiler etc. The only other thing does this particular group have a small electric element fitted like the Strega one?

Kelsey

on 1341123093:

The only other thing does this particular group have a small electric element fitted like the Strega one?

Yes, it does.

beanflying

Makes more sense then. The head will be set to run cooler than ideal but then tweak it electrically up toward the correct temp (possibly adjustable) so if that set point is a touch low (as described and found) then the hot water will raise it up toward brew temp

Kelsey

I guess the real test will come when we next have guests! I never make enough shots in a row to know if a cooling (or heating!) flush would be necessary! Looking forward to finding out tho. Wise words, all - particularly Brett - there's not a chance in hell I'd be doing ANY kind of cutting on this machine!

Kelsey

on 1341126907:

Makes more sense then. The head will be set to run cooler than ideal but then tweak it electrically up toward the correct temp (possibly adjustable) so if that set point is a touch low (as described and found) then the hot water will raise it up toward brew temp

Certainly one aspect of the machine I love is that heated group - the 09 had it too and it really made a difference to the temp stability, I believe. In fact, this machine seems to run hotter than either the BZ09 or the BZ99 - my cups are at an absolutely ideal temperature - verging on being hot. The 09 got them warm, the 99 managed to raise the two espresso cups you can fit in the warmer slightly above ambient.