Hey everyone,

Thought I would start a new thread following on from...

http://www.refrigeration-engineer.co...ad.php?t=26871

Engineer fixed sticking EEV on one unit by swapping over to unused port on outdoor unit... this fixed the issue in cooling however still the problem in heating as described below.

As the units are running in heating on a night we are finding that the unit that was swapped over onto the unused port when this reached thermostat off the coil temp drops to about 26C and the fan comes on now and again to remove the build up of it. I understand the EEV on the unit that is thermo off is 10%.. fair does. This unit is approx 10metres from the outdoor unit.

If one of the other units is at thermo on and the lounge unit which is only 2metres from the outdoor unit is at thermo off the fan runs constant on this unit and the coil will get upto the same temperature as the unit that is at thermo on. This then causes duty loss on the unit that is at thermo on because the fan is constantly running on it.

Engineer has checked the eevs and as these are closing in cooling properly in heating they should be functioning as needed. We also dont think its a control issue as the other units behave as they should as their coils do not build up enough heat input at thermostat off from the EEV 10% opening to keep the fan on... which is how it is designed to run... the issue is with the unit on the shortest pipe run.

LG specify a minimum pipe run of 5 metres between indoor and outdoor unit so engineer has said that it is possible that because of the short pipe run pressure is or isnt dropping (cant remember which he said) by the time the refrigerant has travelled the short 2 metres to the unit that is at thermo stat off, and because the fan is on this causes the pressure to drop/not drop further in the system causing performance loss across the unit that is still at thermo on... does this sound right... its the only thing left that could possibly be wrong. He said to put a coil of pipe behind the unit to bring it upto the required min pipe run then the pressure will/wont drop (cant remember which) in the extra pipework meaning the performance shouldnt drop off as the fan wont be running all the time as less heat input into the coil at thermo off.

We have never increased the pipe run on the 2 meter unit as other engineers have never said to do this.

When all other units are at thermo off and the lounge unit (2mtr run) is at thermo on we get air offs of about 43C which is great and the other coils do not get hot enough to keep the fan on all the time whereas if its the lounge unit at thermo off and one of the other units calling for heat the coil on the lounge unit still gets enough heat input into the coil to make the fan stay on all the time.

Thoughts please...

as usual thanks for any advice you give.

Kind regards

Richard.