Y room 2 n 3 have 70psi when both unit swith on??

[ong]

eariler i went to a client house to troubleshhot a 3 in 1 sanyo unit...

*room 1 - individual compressor (no problem)

*room 2 n 3 - share compressor

*room 2 A/C switch on only
- gas pressure:70psi (offcoil 10-12degre celcius)

*room 3 A/C switch on only
- gas pressure:70psi (offcoil 10-12degre celcius)

*room 2 n 3 A/C switch on
- gas pressure:70psi (offcoil 19-20degre celcius for both room)
- piping size and length : no problem

[Brian_UK]

Are there any solenoid or electronic valves controlling the gas flow to room 2 n 3 ?

[frank]

That sounds like a mis matched system which is how some of these multi spits work.

If you look at the duty available from some Daikin indoor units when connected to a multi split they show a reduced duty when all evaps are on. I'll bet the twin split compressor is rated at 2/3rds of the capacity of both indoor units added together.

How about posting some name plate ratings Ong

[techguy]

[Hi
Whats the model number of the system the indoors may be under sized to compensate for the outdoor capacity. Are the units under high load and whats the return air temp let me know i may be able to help

[ong]

the owner have a new team of technician to check on the system.. so i do not have the chance to check on the technical stuff...but anyway ... what actually is the faults that result to this outcome anyone came across this problem b4 n which to share with us his knowledge??

a normal 2-1 system which i encounter:
when 1 unit is switch on
suction : 63 psi
discharge : 115 psi
offcoil : 13degree celcius for unit 1

when both unit is on:
suction : 85 psi
discharge : 115 psi
offcoil : 12degree celcius for unit 2

[Peter_1]

...If you look at the duty available from some Daikin indoor units when connected to a multi split they show a reduced duty when all evaps are on...

This is because evaporating temperature will increase - compressor can't hold any longer a sufficient low pressure - and so the cooling capacity of each evaportor will decrease (DT between gas and ambient decreases).

[frank]

This is because evaporating temperature will increase - compressor can't hold any longer a sufficient low pressure - and so the cooling capacity of each evaportor will decrease (DT between gas and ambient decreases).

This is exactly what the figures Ong has posted shows

a normal 2-1 system which i encounter:
when 1 unit is switch on
suction : 63 psi
discharge : 115 psi
offcoil : 13degree celcius for unit 1

when both unit is on:
suction : 85 psi
discharge : 115 psi
offcoil : 12degree celcius for unit 2

Look at the increase in suction pressure