CVHE320 PURGE UNIT urgent

[mr hottstepper]

I'm guessing your first language isn't English.

sorry for the spelling errors on my part i text a lot plus i'm using my mobile . and ,english is my first language lol.

[TheChillerMan]

sorry for the spelling errors on my part i text a lot plus i'm using my mobile . and ,english is my first language lol.

I was referring to servicetrane.

[TheChillerMan]

So what are your water pressures and what is the condenser approach?

[mr hottstepper]

because there may not be any non-condensables!

Are you sure about your entering condenser water temp and leaving condenser water temp?

96* entering water would probably cause your high condenser pressure.

You also need to check entering and leaving condenser water PRESSURE. What is the pressure differential? Too low flow will also cause high condenser pressure.

Is the chiller surging?

What are the approaches?

those are the correct wtr temps most of the chillers ive worked on here run with those temps, the ambient temp here is between 85 to 88degf, i cant confirm the water pressure cause guages are screwed, but if i run the back up machine it works fine with the jus about the same condensing temps,the condenser tubes were cleaned couple months ago so. we have good water pressure(assumed), alright heat exchange in tower, thats why i was suspecting the purge unit

[mr hottstepper]

I was referring to servicetrane.

lol sry

[TheChillerMan]

those are the correct wtr temps most of the chillers ive worked on here run with those temps, the ambient temp here is between 85 to 88degf, i cant confirm the water pressure cause guages are screwed, but if i run the back up machine it works fine with the jus about the same condensing temps,the condenser tubes were cleaned couple months ago so. we have good water pressure(assumed), alright heat exchange in tower, thats why i was suspecting the purge unit

I was just verifying because you said your ENTERING water was 96*.

Verify your water flow.

If that is good then check condenser approach.

Compare actual liquid temp to condenser pressure converted to temp. If there is a difference of more than 1-2 degrees then you may have air in the chiller. The wider the difference the more air you may have.

If you have air now check out the purge unit.

Troubleshooting the purge deserves a whole thread of it's own.

[mr hottstepper]

So what are your water pressures and what is the condenser approach?

i really cant tell how many gpms on d condenser cause of the defective guages, i will carry a couple when i return there,but the redundant machine when i run it works well with those condensing tem values

[mr hottstepper]

sorry 96 entering the cooling tower, which would be 96dgf leaving the condenser , sorry abt that

[mr hottstepper]

I was just verifying because you said your ENTERING water was 96*.

Verify your water flow.

If that is good then check condenser approach.

Compare actual liquid temp to condenser pressure converted to temp. If there is a difference of more than 1-2 degrees then you may have air in the chiller. The wider the difference the more air you may have.

If you have air now check out the purge unit.

Troubleshooting the purge deserves a whole thread of it's own.

k thanks alot really appreciate all the help . i didnt think about checking that but my guess is still the purge unit but. why could it have so much air and purge unit not come on ? or maybe there is water in the purge sump? hmmm

[triggerhappy]

k thanks alot really appreciate all the help . i didnt think about checking that but my guess is still the purge unit but. why could it have so much air and purge unit not come on ? or maybe there is water in the purge sump? hmmm

You may be missing the point here.

You need to determine if the machine has air in it first.

If the machine does not have air then your problem is not with the purge.

If the machine does have air and the purge is not pumping out then you need to determine what is wrong with the purge.

Loss of charge, bad compressor(will not pump),restriction or bad txv are the most likely if the compressor is in fact running on the purge unit.

Like I said earlier just valve off the purge unit and it will pump out if the purge is working. You can even introduce some air into the valved off purge to determine if it is working.

This thread has gotten alot more complicated than it really is.

[mr hottstepper]

You may be missing the point here.

You need to determine if the machine has air in it first.

If the machine does not have air then your problem is not with the purge.

If the machine does have air and the purge is not pumping out then you need to determine what is wrong with the purge.

Loss of charge, bad compressor(will not pump),restriction or bad txv are the most likely if the compressor is in fact running on the purge unit.

Like I said earlier just valve off the purge unit and it will pump out if the purge is working. You can even introduce some air into the valved off purge to determine if it is working.

This thread has gotten alot more complicated than it really is.

WILL try what u recommended and let yall know how it goes thanks again for your advice.

[jayguy]

here are the readings,
evap pressure 16hg
cond press-13.5psig
chwe-58degf diff 9degf
chwl-51degf
con-in-96degf
con-out-86degf diff 10degf
current limit setpoint is 81%
water temp set at 50degf...

and trigger is right...this is not that complicated. everybody needs to just slow down. most of the numbers to determine if there is air in the chiller are here.

for R123:
16"Hg = 46F Saturation Temperature
13.5 psig = 117F Saturation Temperature
96F = 4.6 psig Saturation Pressure

ASSUMING a low to very low condenser approach temperature (this can be determined by measuring the ACTUAL chiller liquid line temperature and subtracting the ACTUAL leaving water temperature)...he has about 8 psi of extra head pressure due to air or overcharge....most likely he has air. please verify that the displayed readings are accurate first (including the purge values)...if they are, then use them. if not, don't use them and continue using your measured values.

as for the purge not working, let's assume that the chiller has air in it. the purge compressor and purge fan should be running...if not, investigate and repair. if they are running, then measure the purge compressor suction line (use a bead probe and insulation...i am a HUGE fan of infra-red measuring techniques, but they have their limitations and small, copper lines are a big limitation). if the purge compressor suction temperature READING is the same as what you are MEASURING, then you can bet that it is probably a purge txv or low charge problem. if they do not match, then the purge suction temperature sensor has probably come loose. depending on the purge version, if you are reading an actual temperature on the screen then you have a small thermistor that is screwed into a 'tee' in the purge compressor suction line. the thermistor is NOT sensing the purge refrigerant. the 'tee' is a special fitting that has a small, threaded fitting...refrigerant removal is not required. the thermistor is to be 'baby finger tight' in the tee...more than that and you are going to strip out the thermistor and you will have to buy a new one (or 3 in my case!). do NOT just wire tie it to the side of the suction line...you will be very disappointed.

again, check for air first and when you are done, check it again. working on the purge can suck especially if there isn't any real air in the chiller anyway.

[cperk]

What is the purge operating mode? Is it in adaptive, on or auto? If it's in adaptive or auto it may not run until it's calculated time to purge. For e.g., if the machine has been tight in the past and it only pumped out 5 min. a week then it may have 24 hrs or so, till the purge unit comes on in adaptive mode. My suggestion is to put the purge operating mode to on and see if purge suction starts dropping. If not check purge suction temp. sensor, if O.K. you need to look at all of the things mentioned before. Approach temps. water flows, cond. water entering. Then pull the heads on cond. Question, purge isn't tripped out on max pumpout rate exceeded, is it?