Multiplex

[Rango]

Anyone have any experience with Multiplex drink coolers? I have a few questions.
thanx

[chemi-cool]

YES,
TRY ME.
CHEMI

[Rango]

Many of our units have been retroed with 414b by one of our guys long since gone. How do I tune the charge without any docs. One of our guys says charge to clear glass. Dupont says leave bubbles. But from leak condition (48 degree water) leak repair, evac.

where do we go from here and as I said, how to tune, thats a lot of water to cool before getting an ice bank.

[Peter_1]

This factory is just round the corner (i can see it from here)http://www.packo.com/en/products_pro...&product_id=73
Worked several times on there ice bank systems and they also have milkcoolers working on the same principle.
I should say, fill the sightglass always full with a TEV (of course preferable subcooled liquid). A TEV always needs full liquid, whatever the gas may be, otherwise it will not function properly.
Of course, the Lp will be high, even very high when starting up. Normally, those units have mutch bigger condensors then normal units have, mostly even with HP controlled fans. They also have bigger liquid receivers to store liquid after a normal high-load startup. All the rest remains the same I presume.
Remind that big liquid receivers aren't a necessity. We already installed Carrier chillers of +/- 160 HP without a receiver at all(according to the recommendations of Carrier) It was for me on the 1st sight a very strange recommandation.
They state that the condensor (with a properly selected subcooling coil) must be selected for full load condition. Once you come to partial load condition, you don't need that huge condensor area anymore and there is then plenty 'volume' available for storing the refrigerant.
An i must say, we worked already on full and partial load (till 20%) under outside conditions of -10°C to 35°C without any problem.

[Gary]

If, under heavy load, the coil is fully utilized and the temperature is dropping, then by definition there is enough refrigerant in the system to do the job.

At the other extreme, if there is liquid backing up into the condenser then its capacity is effectively reduced, and the head pressure unnecessarily elevated.

A few intermittant bubbles now and then would seem to indicate the ideal charge.

I prefer to check subcooling and superheat temperatures, and tend to think of the sightglass as a moisture indicator.