how much is enough

[devlin maguire]

Hi all now I know that this is something that is done at design stage, but, I have replaced the comp on a dx system I recovered 21K,s of R22 and the original installer no longer has any record of the work done, what can I do to calculate the total charge without going down the heat load route and can you tell me that if 21 kilo is the correct charge what can I expect for L/S and H/S there is 17 mtr of pipe run 1.1/8 inch and 7/8 inch comp is a maneruo SM 160 scroll
Devlin

[james10]

was it leaking? did it hold pressure after you tested it when you installed compressor, if it held, the charge is more than likely is correct

[NoNickName]

Just do it the old fashion way: sight glass and subcooling.

[devlin maguire]

Hi and thanks for the replys, the comp ran its bearings through oil loss via the stuffing gland so I assume that gas was lost also, so it,s air off minus air on is it. unfortunatly at filter change I did not fit a sight glass and the original is up three flights of steps in an attic ?( yeah I know why is the condensing set not on the roof outside on the same floor as well ?) so whats the TD 4-7 deg C today I put back in the recovered gas but the oil level has risen did the recovered gas bring out the remaining oil and has this now gone in as well will it entrain this excess through the system ? I intend stating it up tomorrow any advice
Devlin

[devlin maguire]

today I put back in the recovered gas but the oil level has risen did the recovered gas bring out the remaining oil and has this now gone in as well will it entrain this excess through the system ? I intend stating it up tomorrow any advice
Devlin

[nike123]

today I put back in the recovered gas but the oil level has risen did the recovered gas bring out the remaining oil and has this now gone in as well will it entrain this excess through the system ? I intend stating it up tomorrow any advice
Devlin

Probably yes.
Oil level should be checked when compressor works for at least 20-30 min at full capacity. If then oil is still high level, than you should remove excess oil . Check oil acidity.
What is application of that unit? Is piping done as it should be (oil traps, etc...)?

[devlin maguire]

Its a air con unit for three seperate areas supplied via trunking with I assume some sort of air flow restrictors/ reducers but I have not got to that stage yet. it was done by Ariedale so it should be cushty, I have not found a trap at all but some of this system has been built around, and some are behind boarding as the pipe runs though a games hall
Dev

[devlin maguire]

I started the unit today and the comp is noisier than I would have expected oil has returned to its proper level, unfortunatly the AHU will not come off heating mode I suspect a controls issue and as there is no documention for this a engineer from the installer is coming to reset the paramaters and trouble shoot the faults,as to the comp noise could this be becuase its trying to cool an excessive heat load, and is a crankcase heater on all the time? also I get light frosting at the second upstream filter and beyond the solenoid up to the tev a danfoss tex 12 with a 3 orifice I check this when the comp was of as I did not want to leave it running unattended as it's a good bit from the outside unit any help would be great
Dev

[devlin maguire]

started the unit today and the comp is noisier than I would have expected oil has returned to its proper level, unfortunatly the AHU will not come off heating mode I suspect a controls issue and as there is no documention for this a engineer from the installer is coming to reset the paramaters and trouble shoot the faults,as to the comp noise could this be becuase its trying to cool an excessive heat load, and is a crankcase heater on all the time? also I get light frosting at the second upstream filter and beyond the solenoid up to the tev a danfoss tex 12 with a 3 orifice I check this when the comp was of as I did not want to leave it running unattended as it's a good bit from the outside unit any help would be great
Dev

[james10]

cch should only energise whilst comp is in standby/off normally fed through the normally closed contactor auxillary,check out the contactor