Multi evaps

[KB Cool]

How do you guys diagnos flow problems when dealing with multi evaps on 1 compressor. I beleive i have one thats overfeeding due to low SH. But, whats odd is my suction psi is low. So maybe i have one thats underfeeding too.:confused:

[craig1]

you have to take the superheat at each evap, not at the compressor. suction pressure could be low due to low load because of bad evaporator fans or an iced up coil

[KB Cool]

But, what psi am i actually reading? The lowest of the 4? There are no pressure taps on evaps.

[bacr]

the first thing you need to do is burn in two access fittings one at each coil and check superheat. If either one is not at ten deg then you will need to make the necessary repairs. the low suction pressure could be plugged dryer, wrong power heads on the TXV's, iced up coil. Are the LLSV open and the LP switch set or working correctly? get the answers to the questions and they will lead you to the solution.

[craig1]

But, what psi am i actually reading? The lowest of the 4? There are no pressure taps on evaps.

neglecting friction loss in the piping, the pressure will be the same at all the evaps, as long as there are no EPR valves.

[absoair]

How do you guys diagnos flow problems when dealing with multi evaps on 1 compressor. I beleive i have one thats overfeeding due to low SH. But, whats odd is my suction psi is low. So maybe i have one thats underfeeding too.:confused:

post your readings

[KB Cool]

post your readings

285 head 35 suction. 28° suction line temp at compressor. A good 110 ambient on the roof yesterday. :eek:
I replaced the shorted out compressor yesterday. And today returned to scope out each evap. Found four little tiny 3 inch fan blades on motors that should be 5 inch.
My 5.5 inch that i had with me won't fit. Ordered blades from case parts and will install when they get here and will take another look. I have a feeling it's just a air flow problem only. But, still i'm not very comfortable dealing with these multiple cases on 1 compressor.