hoshizaki txv problems?

[ac_tom77]

I'm working on a hoshi km630-mah. Had water circuit issues. Got all that worked out and got good water flow and clean water bar. Ran through a few batches and was doing much better but still noticed long feeze time. Pressures about 43/260 about 10-15 minutes into freeze cycle. it will drop to 40 psi just before harvest. harvest pressures are 90/200. Which corresponds ok with the manual. But the red flag to me was it is not making ice the last section of the evap before the out let. and the out let is not freezing back just sweat when it finally will harvest at about 43-45 minutes. I took the TXV bulb of the suction line and held it in my hand for a while and the suction went up about 2 psi to about 45-47. I didn't weigh in charge yet. To me this screams feeding issues but the pressures at 43/260 are per the manual. As i remember shouldn't the suction get down to about 35 or so just before harvest. The evap needs to be cleaned and i have that set up for next week. But that shouldn't affect the evap not producing 100 percent of the plate right? I know cleaning is important first step. Any other suggestions?

[crymtide]

That freeze time is massive. Pressures or not I think the charge might be low, or I have seen the txv bulb being loose and the suction line being uninsulated causing this problem. Hoshis definitely frost the tubing coming away from the evap. Water valve leaking by also causes long freeze with these.

[DoctorIce]

You could unplug the water pump during freeze to both check the freeze pattern and any incoming water problem.

[2sac]

You need to verify proper charge before you condemn the txv.

[bunny]

Verify the charge.

Then check the superheat to verify whether the TEV is performing correctly. Othewise...it's a guess at best.

[ac_tom77]

Got the machine running good now, actually had a leak at the cap tube for High press switch. I was mis lead by decent suction pressure, which was close to spec. I know ur right, gotta weigh in charge before condemming the txv. Thats what i get for trying to over diagnose. Lesson learned, moving foward, thanks for the input though everybody!