Pete L
26-11-2007, 01:01 PM
Am having real problems getting a dehum. to run properly.Unit is an Ebac which had a seized tecumseh rotary compressor. Exact replacement compressor only available on long lead time so ended up with similar sized (in cc's) Samsung unit. Set up is very simple with compressor, coil, pencil filter, capillary and hot flush solenoid valve.
Problem is that after a minute or 2 running, the gauge set goes into a vacuum, with the capillary heavily frosted. System is running on R22 but originally was 407c - but coil was repaired (original problem was refrigerant leak) and flushed prior to refitting. System charged with same wt of R22 as 407c and new filter fitted. Ambient temp 17-18C.
Thinking refrigerant level was low I added R22 and there was a slight improvement(ran a few minutes longer before vacuum) but ended up with twice specified refrigerant wt and decided this could not be right! knowing that dehum's are normally used in warm rooms, increased ambient to 24/25C and then system ran OK, ie 20 minutes refrigeration and 10 mins defrost. This is fine but surely cannot be right? Whilst not being very effective it ought to run at lower ambient temps I would have thought.
Spoke to friend in trade and he suggested capillary size may not be compatible for R22, so I removed refrigerant, disconnected coil and flushed and fitted second new filter(cut open first replacement and it was clean inside), vacuumedd and recharged with 407c. Same thing happened, within a minute or 2 gauge drops to vacuum. Have not tried increasing wt of refrigerant or increasing ambient but suspect results will match R22. Am I missing something obvious here?
I had wondered about moisture in system, causing cap blockage, but I vacuum for an hour every time and it's only a small system! If I fire up the solenoid flush valve manually, suction side comes out of vacuum within a minute or so, but then goes back to vacuum pretty quickly when flush valve closed. I have shortened capillary tube each time I have refitted it, probably 6 inches shorter than original, but cannot believe that would have had such an effect.
What am I overlooking?
Problem is that after a minute or 2 running, the gauge set goes into a vacuum, with the capillary heavily frosted. System is running on R22 but originally was 407c - but coil was repaired (original problem was refrigerant leak) and flushed prior to refitting. System charged with same wt of R22 as 407c and new filter fitted. Ambient temp 17-18C.
Thinking refrigerant level was low I added R22 and there was a slight improvement(ran a few minutes longer before vacuum) but ended up with twice specified refrigerant wt and decided this could not be right! knowing that dehum's are normally used in warm rooms, increased ambient to 24/25C and then system ran OK, ie 20 minutes refrigeration and 10 mins defrost. This is fine but surely cannot be right? Whilst not being very effective it ought to run at lower ambient temps I would have thought.
Spoke to friend in trade and he suggested capillary size may not be compatible for R22, so I removed refrigerant, disconnected coil and flushed and fitted second new filter(cut open first replacement and it was clean inside), vacuumedd and recharged with 407c. Same thing happened, within a minute or 2 gauge drops to vacuum. Have not tried increasing wt of refrigerant or increasing ambient but suspect results will match R22. Am I missing something obvious here?
I had wondered about moisture in system, causing cap blockage, but I vacuum for an hour every time and it's only a small system! If I fire up the solenoid flush valve manually, suction side comes out of vacuum within a minute or so, but then goes back to vacuum pretty quickly when flush valve closed. I have shortened capillary tube each time I have refitted it, probably 6 inches shorter than original, but cannot believe that would have had such an effect.
What am I overlooking?