pumping down

[Matty]

hi guys...
I installed a vrviii about a year ago serving 5 fan coils, my client wanted two additional units installed this week...how the hell do i pump it down /will it pump down???? or will i have to recover it all ??

anyone know ?

[Brian_UK]

All depends what the overcharge amount is.

Try connecting a reclaim cylinder to the liquid line and getting as much out as you can that way, then try a pumpdown.

[Matty]

cheers.....theres the original 9.7k plus a further 11.6 (i think?) at the moment....

[Brian_UK]

Ah well, maybe more than one tank then.

[coolments]

Hi Mat, try pumping down as far as it will go then shutting down the service valves and connect a reclaim machine up to shove the rest into the condenser via a service valve inside the condenser, if it wont take it then then a decant cylinder will be required to take the extra, thats if your sure the charge is correct at the moment, if not its always wise to decant the lot out and weigh it just to be sure there are no problems before you do the work and then recommission the system.

[monkey spanners]

Hi Matty,

Be carefull when pumping down, the condenser is the same as a gas bottle in that it will need 20% or so expansion volume to be safe, if you pump it down till the hp trips i doubt you will have much room for expansion left.
I'd get a couple of reciever cylinders from the wholesalers to hold the complete charge whilst the work is carried out. Unlike recovery cylinders reciever cylinders are cleaned out before being hired out again so this should help keep the refrigerant clean.

Jon

[Thana]

Matty, it's a good idea for you to recover the gas to check the charge is correct anyway I know it sounds a hard work but it may save you in the long run. The safest way for you to recover is in mode 21..on the outdoor unit this will open all the expansion valves and solenoid valves in the outdoor and the indoor units..( do you have enough capacicty on the max index for you to ADD more indoors worth checking) To do this you need to get into mode 2 on the outdoor unit, you do this buy pushing and holding the mode button for 5 sec which will put on H2P, on the left (not flahing) you then press the set button 21 times as this is a binary number system you should now have lights H7P (being 1) then H5P (being 4) then H3P (being 16) total 21.. then push the return button once, which light's H6P then the set button once, giving H7P lit, press the return button twice you should here the solenoids click, now your in mode 21.. you can recover ALL the gas and pressure test and vac no worries.. leave this like this till you recharge the system. to reset push the mode button once to come out of this mode, you can now address the new fan coils and push the reset button 5 secs and now your ready to roll.