Hey all,
So I've replaced a working 3ton Liebert R-22 split (customer wanted something newer) with a new 3 ton R-407c Liebert split. They're pretty much like for like other than the AHU having a physically larger footprint. Both systems run off of POE oil, so I just cleaned out the pipework and reused 1/2 of it. Pipe sizing is spot on for this swap. I started up the system and have very odd symptoms. I'll jot down all info I took to see if anyone would have feedback. Keep in mind that I repaired a leak on a quick connect fitting that I didn't tighten enough. I've added gas until I got 10-12*f subcooling. Even with the leak of FACTORY CHARGE I had the same symptoms below:
- 3ton 407c split (with hotgas bypass)
- pipe run = 25' of 3/8" & 7/8"
- Condensing unit and AHU came with factory charges (not sure how much tho - it wasn't printed on the equipment)
- Serving a server room where the prior 3 ton handled no problem
- Room is HOT (90*f Return air)
- I'm only getting 85*f supply (TD of 5*f across coil)
- Suction pressure of 135psi (WAY too high..much higher than it should be even with 90*f RA) - No signs of sweating anywhere other than downstream of the quench valve.
- Head pressure of 230psi (outdoor air is 85*f)
- Subcooling at 11*f
- Superheat at 10*f - This is throwing me off
- Compressor amps @ 8.7 / 13.5 RLA (SCROLL comp)
- sightglass @ full column of liquid
Both the suction and liquid lines are so close in temp. liquid line temp @ 91*F. Suction line temp was at like 86*f. (both taken at outlet of condenser.)
I've checked to make sure that the TXV bulb is correctly attached.
The valve is non adjustable.
I've taken the hotgas bypass out of the equation by powering down its solenoid - same symptoms.
Right now, I'm going to return tomorrow and swap out the TXV as I think it's stuck WIDE open. You'd think that my superheat (11*f) or compressor amps (roughly 60%RLA) would indicate otherwise tho.
Any advice is much appreciated
Cheers
-Slick
So I've replaced a working 3ton Liebert R-22 split (customer wanted something newer) with a new 3 ton R-407c Liebert split. They're pretty much like for like other than the AHU having a physically larger footprint. Both systems run off of POE oil, so I just cleaned out the pipework and reused 1/2 of it. Pipe sizing is spot on for this swap. I started up the system and have very odd symptoms. I'll jot down all info I took to see if anyone would have feedback. Keep in mind that I repaired a leak on a quick connect fitting that I didn't tighten enough. I've added gas until I got 10-12*f subcooling. Even with the leak of FACTORY CHARGE I had the same symptoms below:
- 3ton 407c split (with hotgas bypass)
- pipe run = 25' of 3/8" & 7/8"
- Condensing unit and AHU came with factory charges (not sure how much tho - it wasn't printed on the equipment)
- Serving a server room where the prior 3 ton handled no problem
- Room is HOT (90*f Return air)
- I'm only getting 85*f supply (TD of 5*f across coil)
- Suction pressure of 135psi (WAY too high..much higher than it should be even with 90*f RA) - No signs of sweating anywhere other than downstream of the quench valve.
- Head pressure of 230psi (outdoor air is 85*f)
- Subcooling at 11*f
- Superheat at 10*f - This is throwing me off
- Compressor amps @ 8.7 / 13.5 RLA (SCROLL comp)
- sightglass @ full column of liquid
Both the suction and liquid lines are so close in temp. liquid line temp @ 91*F. Suction line temp was at like 86*f. (both taken at outlet of condenser.)
I've checked to make sure that the TXV bulb is correctly attached.
The valve is non adjustable.
I've taken the hotgas bypass out of the equation by powering down its solenoid - same symptoms.
Right now, I'm going to return tomorrow and swap out the TXV as I think it's stuck WIDE open. You'd think that my superheat (11*f) or compressor amps (roughly 60%RLA) would indicate otherwise tho.
Any advice is much appreciated
Cheers
-Slick
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