So... What's the problem here?

[jpsmith1cm]

Hopefully the picture I took of the DRSA is adequate to provide all refrigerant side data.

Problem is this:

Dual temp single deck case would NOT hold temp in LT mode. Did a 'fair' job in MT.

Tech#1 was out and condemned the powerhead and when that did nothing, replaced the whole TXV. When THAT didn't work, I was called in.

Cut in a pressure tap and SG on the liquid line to confirm quality of liquid and the pic I posted gives the results. Sightglass was perfectly solid.


So. Fire away.

[air2spare]

restriction in 1 or more distributor cap tubes?

[I_bend_metal]

Seeing as how I am a former resi guy and new to the refer tech gig, I'm
going to take baby steps on this one....

Am I correct in thinking that suction PSI is too low?

(or do I need to head back to class?)

[dangpgt97]

restriction in 1 or more distributor cap tubes?

I was thinking the same. Maybe the nozzle is plugged. Or possibly a plugged external equalizer line for the txv...

[Herb1025]

What type of txv ? is their an EPR to tell the system if it's MED or LT? I have seen some with a solenoid by pass.

[mccool]

Liquid line drier in case was partially plugged, S.G. was cut in before drier??

What are the components in each case?
Suction line solenoid with 90 degree EPR for MT operation?

[NANOTECH]

CRO valve not set correctly or switchover solenoid not working properly

[jpsmith1cm]

What type of txv ? is their an EPR to tell the system if it's MED or LT? I have seen some with a solenoid by pass.

Externally equalized Sporlan BQ type TXV. Orifice if properly sized.

Liquid line drier in case was partially plugged, S.G. was cut in before drier??

What are the components in each case?
Suction line solenoid with 90 degree EPR for MT operation?

Forgot to add that Tech#1 replaced case drier. SG was installed after drier anyway.

CRO valve not set correctly or switchover solenoid not working properly

Pressures taken at coil, upstream of DT solenoid/ORIT valve.

[jpsmith1cm]

restriction in 1 or more distributor cap tubes?

Even frost pattern on all tubes. Took the nozzle out and inspected. All clean and clear.

Seeing as how I am a former resi guy and new to the refer tech gig, I'm
going to take baby steps on this one....

Am I correct in thinking that suction PSI is too low?

(or do I need to head back to class?)

Actually, the suction pressure is a wee bit high, but not terribly so. The case MFR calls for -22 degrees SST.

I was thinking the same. Maybe the nozzle is plugged. Or possibly a plugged external equalizer line for the txv...

I even replaced the external eq line to no effect.

[jpsmith1cm]

This was a tough problem.

I had to bring in factory support and he made it so simple that I felt like an idiot.

[KB Cool]

Is the txv adjustable. If so. Open it up a few turns

[dangpgt97]

hmmmmmmmmmmmm. Is this an open air case where a heat duct or something could be disrupting the air curtain?

[mccool]

Factory styrofoam peice at top behind discharge honeycomb was too big, (cut on wrong angle)blocking majority of airflow.
Found this on several Hill end bunks at same store.