halfcan
16-07-2014, 11:39 AM
Hi guys,
Hopefully someone can help here:
We've been having problems with a York YCUA150 condenser feeding a cooling coil in an AHU.
I was originally called to site due to having a leak on the system at the outlet of the compressor discharge pipe. Once the leak was repaired, we charged the circuit with 29kgs of R407C (as found in the original commissioning data).
When I run the system up, within minutes the discharge pressure rises and keeps rising until it cuts out on 28bar. However, the condenser fans run ok, the coil appears clean and free of obstruction, and all solenoid valves are open. The system has 2 circuits that are operated through the same condenser (seperate coils either side) and 1 circuit runs fine all the time.
My operating readings are:
Ambient temp - 23 deg C
Standing pressure - 9 BarG
Suction pressure - 4.5 BarG constant
Suction saturated temp - 0 deg C
Evap outlet temp - 7 deg C
Sucion s/heat - 7K
Suction pipe temp at compressor inlet - 4 deg C (I find this odd)
S/heat at compressor - 4K (see above)
Discharge pressure - 25 bar (I manually cut compressor at this pressure but all following readings are relative)
Discharge temp - 61 deg C
Discharge pipe temp - 61 deg C
Discharge superheat (desuperheating) - 0K (very odd)
Liquid line temp outlet of condenser - 32 deg C
Subcooling - 29K
Liquid line temp before TEV - 32 deg C
Suncooling - 29K
As you can see from my readings, there is no discharge superheat at all it seems. I find it odd that the discharge pipe at the compressor would be the same temp as the saturation temp in the condenser.
Another reading that concerns me, is that there is no temperature difference across the evaporator....after the expansion valve I measured 7 deg C, and at the evaporator outlet I measured 7 deg C, yet the evap coil is in the same AHU as th circuit that runs continuously and is fine.
I also find it odd that the evaporator outlet is approx 7degC but my compressor inlet is 4degC...
Unfortunately I didn't take many readings from the circuit running fine, only that the Suction pressure was also about 4.5 bar and the discharge pressure was approx 18.5 bar.
If I remember any other info I will add.
Any feedback would be very helpful, cheers guys.
Hopefully someone can help here:
We've been having problems with a York YCUA150 condenser feeding a cooling coil in an AHU.
I was originally called to site due to having a leak on the system at the outlet of the compressor discharge pipe. Once the leak was repaired, we charged the circuit with 29kgs of R407C (as found in the original commissioning data).
When I run the system up, within minutes the discharge pressure rises and keeps rising until it cuts out on 28bar. However, the condenser fans run ok, the coil appears clean and free of obstruction, and all solenoid valves are open. The system has 2 circuits that are operated through the same condenser (seperate coils either side) and 1 circuit runs fine all the time.
My operating readings are:
Ambient temp - 23 deg C
Standing pressure - 9 BarG
Suction pressure - 4.5 BarG constant
Suction saturated temp - 0 deg C
Evap outlet temp - 7 deg C
Sucion s/heat - 7K
Suction pipe temp at compressor inlet - 4 deg C (I find this odd)
S/heat at compressor - 4K (see above)
Discharge pressure - 25 bar (I manually cut compressor at this pressure but all following readings are relative)
Discharge temp - 61 deg C
Discharge pipe temp - 61 deg C
Discharge superheat (desuperheating) - 0K (very odd)
Liquid line temp outlet of condenser - 32 deg C
Subcooling - 29K
Liquid line temp before TEV - 32 deg C
Suncooling - 29K
As you can see from my readings, there is no discharge superheat at all it seems. I find it odd that the discharge pipe at the compressor would be the same temp as the saturation temp in the condenser.
Another reading that concerns me, is that there is no temperature difference across the evaporator....after the expansion valve I measured 7 deg C, and at the evaporator outlet I measured 7 deg C, yet the evap coil is in the same AHU as th circuit that runs continuously and is fine.
I also find it odd that the evaporator outlet is approx 7degC but my compressor inlet is 4degC...
Unfortunately I didn't take many readings from the circuit running fine, only that the Suction pressure was also about 4.5 bar and the discharge pressure was approx 18.5 bar.
If I remember any other info I will add.
Any feedback would be very helpful, cheers guys.