RONB
22-06-2011, 07:44 PM
Hi All
I am currently working on a HT pack on R422D. The plant has just been fitted with LPA and I am in the process of dropping the head pressure setting. The problem I have is as follows. The current head press control is set to 165 psi,the set point I am trying to achieve is 150 psi. The plant was very low on refrigerant before the works started and the encumbant contractor added approx 150 kg of R422D.The refrigerant has quite a large glide and the problem I am getting is when I dropped the HP control to 150 psi the head pressure shot up to around 200 psi all the condenser fans were running at full speed (inverter controlled). What I am wondering is if the refrigerant has lost its blend and the charge is topped up with new gas, with me dropping the head pressure to 150 psi with the gas condensing at different pressures could the condenser be logging with liquid from part of the blend and cause the head pressure to rise. I am at a total loss with this problem. I have checked the NRV on the LPA bypass and it is holding ok as I thought it could be the problem.
I am currently working on a HT pack on R422D. The plant has just been fitted with LPA and I am in the process of dropping the head pressure setting. The problem I have is as follows. The current head press control is set to 165 psi,the set point I am trying to achieve is 150 psi. The plant was very low on refrigerant before the works started and the encumbant contractor added approx 150 kg of R422D.The refrigerant has quite a large glide and the problem I am getting is when I dropped the HP control to 150 psi the head pressure shot up to around 200 psi all the condenser fans were running at full speed (inverter controlled). What I am wondering is if the refrigerant has lost its blend and the charge is topped up with new gas, with me dropping the head pressure to 150 psi with the gas condensing at different pressures could the condenser be logging with liquid from part of the blend and cause the head pressure to rise. I am at a total loss with this problem. I have checked the NRV on the LPA bypass and it is holding ok as I thought it could be the problem.