Riser

[sharonrod]

Hi guys

I am going to install a 12.000 btu and an 18.000 btu split type airconditioners, there will be a riser of about 18 mtrs... should i use oil traps although i will be use r 410a? splits units are not inverters.

[bill1983]

hi sharonrod,
if the system you are using guarentees full load at all times then the velocity of the refrigerant will be constant. however this is never the case. because the load changes as the space approaches or departs from design temperature, then the refrigerant velocity will also change from that which is ideal for oil retun. you must employ the use of traps along the riser to ensure oil entrapment at various stages. it has been a while since i carried out installations so i am unsure offhand as to the recommended hight to install the traps. if you wait awhile, somebody will either confirm my answer and enhance it, or correct it.

[Peter_1]

I should install one, we recommend one each 9 meter

[bill1983]

why 9 meter Peter? is that recommended for all pipe sizes or just a general rule of thumb?