CVHF surging

[murphman]

would love some input on surging on a trane cvhf. Both pressure drops match specs, no excessive pumpouts on purge, ref. level slightly high, tower water temp at 65. Also wondering if condenser approach is an indication of air in system or just fouled tubes?? Any input greatly appreciated.... just getting into chiller work thanks

[absrbrtek]

Crap shoot with the kinda info you gave. Need real information to give you a real answer. Water temp in, water temp out of both barrels, SH, SC, DSH, pressures, LL temp, type refrigerant, approaches, amperages, % of FLA, etc.

[ryjowy]

Both approaches should run pretty close to each other. Check your design delta T's. Make sure you have temp drop as well as pressure drop. Tubes could be fouled. Good rule of thumb is 10* @ full load. 1 degree less for every 10% short FLA.

[Tranetek]

It is usually one of three things. Air, condenser water to hot or fouled tubes. Condenser approach should be no more then 3 degrees at full load. Have you checked to see if your purge is actually working properly?

[manny238]

tower water temp at 65??

[chillrdude]

Have you put an actual gauge on the machine or are you getting your "pressures" from the micro.

[socal13]

No excessive pump outs ? What is your purge setting , auto, adaptive, on ,off.

[Healey Nut]

Gotta luv the newbies?????
" Chiller's Surging" whats up wiv it ?????
With 65 degree tower water and who knows what load maybe its a low load surge ????

[chiller mekanik]

Please post a log............

[Chiller Guy]

AS the other guys mentioned, there is not enough info in your post to arrive at a firm answer. However; if we look at the cause of " surge" perhapps you will find the cause.

Surge happens when the impeller "stalls" (will not pump) because the differential pressures (between Evap and Cond) are greater than the designed "Lift " of the impeller. In other words the impeller cannot lift the refrigerant vapor from the evap pressure to the cond. pressure.

Anything that is causing your machine to have a higher than normal pressure (cond) OR, a lower than normal pressure (evap) can cause surge.

AS mentioned also, do not depend on the micro to give you correct readings. Go for the service tools (gauges and thermo's) to double check.

Good luck and keep us posted

[absrbrtek]

A stall is not a surge. Stalling occurs before surging.

Surge happens when the impeller "stalls" (will not pump) because the differential pressures (between Evap and Cond) are greater than the designed "Lift " of the impeller. In other words the impeller cannot lift the refrigerant vapor from the evap pressure to the cond. pressure.

[turbomaster]

I have a paper around here somewhere that describes what "York" put out as "rotating stall". It was primarily a low load condition that I was assured would not harm the machine. This was on a single wheel 123 chiller. It sounded like a loud grumbling sound, not a whole lot of amp fluctuation or pressure swings like you see with a "surge" surge. I'll have to dig it out of the archives, be a good excuse to go get another cold one!!!

[turbomaster]

Found it, let me get it scanned in and I'll be happy to send it to those interested, it is a very good description of what is going on in a stall condition.