Two Suction LInes?

Wayne_31

to keep the refrigerant velocity high for oil return. Are there any oil traps in the lines? How that works is the traps fill with oil, when the velocity is high enough the refrigerant vapors bring the oil back to the compressor body.

Minnesota Wayne

Reuben Saltzman

Two Suction Lines?

Why would a suction line split off in to two suction lines off a single condenser on a split AC system? They both feed to the same air handler in the attic on a high-velocity system.

Unknown

Ask Professor Silberstein!

You may get a better response if you try there.

Dave

Bob Forand

Perhaps

Perhaps someting happened to once side of the lineset, a kink in the line or a restriction ? Or maybe the air handler is over the long length requirement. I would bet a problem with the lineset though.

Dan Foley

Two Lines

The old ('60's & '70's) vintage Bryants used to do this with the larger sizes. I don't know why but my guess would be to keep the velocity up for oil return to the compressor. - DF

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John Mills_4

Space Pak

Yea, the original Dunham Bush installations often had that kind of lineset. Can tell installers along the way reused instead of doing what the outdoor unit manufacturer called for.

Baltimore/Maine Doug_7

Curiousity question about velocity

If there are two returns and the vapor is split into two flows, is not the velocity half in each return because the volume is half?

Wayne_30

The suction lines are different sizes

The suction lines are different sizes with oil traps in each line. The low velocity allows the oil to seal the trap. Now all the reffrigerant vapor travels in the open pipe. When the refrigerant flow increases the trap closed with oil, opens up bringing the oil and refrigerant gasses back to the compressor. When the flow decreases, the larger line trap seals again forcing the refrigerant to travel in the smaller line, until the process starts over again. All without any mechanical valves, or switches.

Minnesota Wayne

Tim_32

Unloading compressor??

It sounds like the condensing unit is lower than the evaporator coil, if this is the case I doubt its a double suction RISER. Double suction risers are usually seen where the condensing unit is higher than the evap coil and when you have more than one stage of compressor operation

TRN

Sucton lines

Is there a two-circuit evap in the air handler? Those lines look too large to be able to keep up the velocity needed for proper oil return. If it is an old line set that has been reused, it would be better and more efficent to replace it with a properly sized one.

Techman

Double

Whats up with the two low volt thermostat wirers?

TRN

wirers?

Back in the olden days, when NH3 was widely used in such systems. It was around 1912 a fellow named Midgely developed a refrigerant called Freon-12. It was a boon. They could actually pipe two seperate, distinct back & forth piping runs in one evaporator. They maintained the same names as was used for NH3 and called them 'refrigerant circuits". Granted there has developed a low voltage control system to let the refrigerant flow through them circuits, dependin on the need of course, to be-a pickin up them BTU's frum that thar air. That then causes the phase change, not to be confused by some as swapping two wires of an electrical system.