Mitsubishi R2 - Pump Down

[AbsoluteWDJ]

Evening All.

We have six PURY-EP400YJM-A's to pump down and relocate a couple of fan coils on each. Does anyone have experience or recommendations on the best procedure to pump these systems down taking into account that there are two outdoor modules.

Should I operate them in cooling for a while and then begin to close high pressure pipes on OC & OS or close high pressure pipe first OC & OS and then operate in test run cooling?

Should I use pump down mode (SW2 - 4-ON) or Cooling test run?

Should I disconnect any hot gas bypass solenoid coils?

What sort of pressure should I expect these to pump down too?

Any advice welcome

Regards

[install monkey]

mitsi dont recommend pumping down systems- also you have the problem that if you do-then after relocating your indoors-when pressure testing the system you could lose nitrogen into the condenser-thus more problems- just get a big reclaim bottle- also the charge may need to be ammended if any big differences in length of piperuns- better to cover all bases-gives you time to prep indoors ready for relocating whilst degassing

[stufus]

I'm with the monkey on this one ,not a fan of pumping down any manufacturers VRF kit due to the strain it puts on the kit and the amount of refrigerant potentially involved.
Close the valves on the outdoors and recover what's in the lines.
Cheers
Stu

[AbsoluteWDJ]

Thanks Gents.

I did speak to Mitsubishi about pumping down twinned outdoor modules. Their procedure was as follows:

Set fan coils into cooling mode but don't switch on.
Close both OC & OS high pressure service valves.
Close OS low prsssure service valves.
Set SW3 - 1&2 - ON - Test run.

Having done this (late afternoon in central London)i discovered the OS system operated with both valves already closed, so no pumping down. Hence the questions from original post.

I'm siding with the idea to shut the valves down and reclaim remaining gas into receiver bottle. If I decide to do this would it best to operate the system in a particular mode so that refrigerant accumalator's are at their highet level, leaving minimal left in interconnecting pipe work. I'm on the understanding this would happen if all fan coils are in heating mode, is this correct?

[JoeAT50A]

Conduct from OC, here
-----------------------------------------------------------------------
[5] Refrigerant Leak
1. Leak spot: In the case of extension pipe for indoor unit (Cooling season)
1) Mount a pressure gauge on the service check joint (CJ2) on the low-pressure side.
2) Stop all the indoor units, and close the high-pressure side refrigerant service valve (BV2) on the outdoor unit while the compressor
is being stopped.
3) Stop all the indoor units; turn on SW2-4 on the outdoor unit control board while the compressor is being stopped.(Pump down
mode will start, and all the indoor units will run in cooling test run mode.)
4) In the pump down mode (SW2-4 is ON), all the indoor units will automatically stop when the low pressure (63LS) reaches
0.383MPa [55psi] or less or 15 minutes have passed after the pump mode started. Stop all the indoor units and compressors
when the pressure indicated by the pressure gauge, which is on the check joint (CJ2) for low-pressure service, reaches
0.383MPa [55psi] or 20 minutes pass after the pump down operation is started.
5) Close the service ball valve (BV1) on the low-pressure pipe on the outdoor unit.
6) Collect the refrigerant that remains in the extended pipe for the indoor unit. Do not discharge refrigerant into the atmosphere
when it is collected.
7) Repair the leak.
8) After repairing the leak, vacuum*1 the extension pipe and the indoor unit.
9) To adjust refrigerant amount, open the ball valves (BV1 and BV2) inside the outdoor unit and turn off SW2-4
--------------------------------------------------------------------------
3. Leak spot: In the case of extension pipe for indoor unit (Heating season)
(1) Run all the indoor units in heating test run mode.
1) To run the indoor unit in test run mode, turn SW3-2 from ON to OFF when SW3-1 on the outdoor control board is ON.
2) Change the setting of the remote controller for all the indoor units to the heating mode.
3) Check that all the indoor units are performing a heating operation.
(2) Stop all the indoor units, and stop the compressor.
1) To stop all the indoor units and the compressors, turn SW3-2 from ON to OFF when SW3-1 on the outdoor control board is ON.
2) Check that all the indoor units are stopped.
(3) Close the ball valves (BV1 and BV2).
(4) Collect the refrigerant that remains inside the indoor unit. Do not discharge refrigerant into air into the atmosphere
when it is collected.
(5) Repair the leak.
(6) After repairing the leak, perform evacuation of the extension pipe*1 for the indoor unit, and open the ball valves (BV1
and BV2) to adjust refrigerant.
------------------------------------------------------------------------

It's not pumpdown procedure, but sort of similar for you to have an idea of pumpdown.

Hope this help.

[AbsoluteWDJ]

Conduct from OC, here
-----------------------------------------------------------------------
[5] Refrigerant Leak
1. Leak spot: In the case of extension pipe for indoor unit (Cooling season)
1) Mount a pressure gauge on the service check joint (CJ2) on the low-pressure side.
2) Stop all the indoor units, and close the high-pressure side refrigerant service valve (BV2) on the outdoor unit while the compressor
is being stopped.
3) Stop all the indoor units; turn on SW2-4 on the outdoor unit control board while the compressor is being stopped.(Pump down
mode will start, and all the indoor units will run in cooling test run mode.)
4) In the pump down mode (SW2-4 is ON), all the indoor units will automatically stop when the low pressure (63LS) reaches
0.383MPa [55psi] or less or 15 minutes have passed after the pump mode started. Stop all the indoor units and compressors
when the pressure indicated by the pressure gauge, which is on the check joint (CJ2) for low-pressure service, reaches
0.383MPa [55psi] or 20 minutes pass after the pump down operation is started.
5) Close the service ball valve (BV1) on the low-pressure pipe on the outdoor unit.
6) Collect the refrigerant that remains in the extended pipe for the indoor unit. Do not discharge refrigerant into the atmosphere
when it is collected.
7) Repair the leak.
8) After repairing the leak, vacuum*1 the extension pipe and the indoor unit.
9) To adjust refrigerant amount, open the ball valves (BV1 and BV2) inside the outdoor unit and turn off SW2-4
--------------------------------------------------------------------------
3. Leak spot: In the case of extension pipe for indoor unit (Heating season)
(1) Run all the indoor units in heating test run mode.
1) To run the indoor unit in test run mode, turn SW3-2 from ON to OFF when SW3-1 on the outdoor control board is ON.
2) Change the setting of the remote controller for all the indoor units to the heating mode.
3) Check that all the indoor units are performing a heating operation.
(2) Stop all the indoor units, and stop the compressor.
1) To stop all the indoor units and the compressors, turn SW3-2 from ON to OFF when SW3-1 on the outdoor control board is ON.
2) Check that all the indoor units are stopped.
(3) Close the ball valves (BV1 and BV2).
(4) Collect the refrigerant that remains inside the indoor unit. Do not discharge refrigerant into air into the atmosphere
when it is collected.
(5) Repair the leak.
(6) After repairing the leak, perform evacuation of the extension pipe*1 for the indoor unit, and open the ball valves (BV1
and BV2) to adjust refrigerant.
------------------------------------------------------------------------

It's not pumpdown procedure, but sort of similar for you to have an idea of pumpdown.

Hope this help.

Thanks Joe

Would you close both high pressure pipes OS & OC. Operate SW2-4 with a low pressure gauge on both low pressure pipes OS & OC. Then shut down both OS & OC low pressure pipe valves when pressure nears 55psi, or do you carry out low pressure shut down on OC only?

[JoeAT50A]

Pressure reading 55 psi from just OC, and of course shut down all the ball valves of OC, OS1 and OS2 (if any).
Pumpdown program run same speed/same timing for both OC and OS.

I believed you known which one is the OC for 2xPURY-EP200YJM-A.
OC was determine by capacities of outdoor units and biggest capacity unit of combination will be the OC.
If capacities are same like PURY-EP400YJM-A = 2xPURY-EP200YJM-A, then lowest Mnet address will be the OC.