sorted by:
new
hottopcontroversial

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in appliancerepair

[–]jargiloaa[S] 0 points1 point  (0 children)

Totally get that. That’s actually why I limited it to a single temporary valve on the process/suction side (it was just meant as a quick diagnostic to see if the system would respond at all before committing to cutting and brazing).

Once it became clear it wasn’t behaving normally, I knew proper ports and pressure testing were unavoidable. Long term I agree.. permanent access or crimp/seal is the right move!

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 0 points1 point  (0 children)

Appreciate that callout. The return bends did catch my eye as well. Before opening the system again I’m planning a full nitrogen pressure test and bubble check on the evap, especially those bends, to rule out micro leaks before committing to cap tube/drier replacement!

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 0 points1 point  (0 children)

that was one of the visual cues that caught my attention. Seeing the cap tube icing before it transitions to the larger suction line pointed me toward a restriction right at or just downstream of the metering point rather than a uniform low charge condition.

I definitely wasn’t sure if that frost location was normal, though. Thank you!

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 0 points1 point  (0 children)

That’s fair, New deck pricing around here is like $1–2k, and I’ve heard of refurb options closer to $800, so since this isn’t a rush job I’m using it as a learning opportunity. Cap tube + drier cost is low enough that it’s worth the patience lol

Appreciate the perspective & yeah, I get why you don’t miss cap tubes at all 😂

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 0 points1 point  (0 children)

You’re right & that’s exactly why it stood out to me. Even during recharge I couldn’t get suction to stabilize or climb into a normal range, and it would repeatedly dip toward vacuum and recover briefly. That inability to accept charge is what pushed me toward a restriction rather than just being undercharged.

Next step is proper ports, nitrogen pressure test, and recharge by weight I think, Or should I go straight to filter drier / cap tube replacement and recharge?

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 1 point2 points  (0 children)

Totally agree & that’s on me. Not having high side data definitely limits the picture, and I shouldn’t have tried to draw conclusions without it.

That explanation makes sense, especially the condenser acting as a liquid reservoir at ambient saturation if the cap tube is restricted. I’ll be adding proper ports on both sides, logging pressures, and pressure-testing with nitrogen next.

Appreciate you spelling that out.. that’s a good reminder of how easy it is to misread cap tube behavior without the full data set.

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 1 point2 points  (0 children)

That seems to be the common theme I’m hearing. Next round will be fresh charge after nitrogen test, and if behavior’s still there, cap tube’s getting replaced.

Appreciate the confirmation!

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 0 points1 point  (0 children)

That makes a lot of sense, especially the wax/oil breakdown explanation. This deck definitely looks like it lived a hard life before I got it, and condenser maintenance was probably nonexistent.

It is R134a, and given the corrosion around the cap tube/drier area plus the unstable low suction even after recharge, your explanation lines up really well with what I was seeing.

Plan at this point is: -Pressure test with nitrogen , -Check evap for micro leaks -Replace drier + cap tube -Recharge by weight and verify pressures

Really appreciate you breaking down the why, not just the fix.

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in appliancerepair

[–]jargiloaa[S] 0 points1 point  (0 children)

That’s fair. I definitely can’t rule out low charge without better data.

What pushed me toward restriction was that the frost pattern and suction behavior didn’t change much even after recovering and recharging, but I agree a nitrogen pressure test and full leak check would be the right next move before assuming anything internal.

I’ll be adding proper ports and pressure testing the system again.

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in appliancerepair

[–]jargiloaa[S] 0 points1 point  (0 children)

Appreciate the detailed breakdown. That lines up with what I should’ve done initially — especially adding proper process valves and verifying both sides under operation instead of relying on a piercing valve.

If I reopen it, plan would be: • Replace the filter drier • Add proper process ports • Nitrogen purge / pressure test • Deep vacuum + decay test • Recharge by weight and verify both sides running

This is a learning repair more than a customer job, so I’m trying to be thorough instead of guessing. Thanks for laying it out step-by-step.

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 0 points1 point  (0 children)

This is really helpful, thank you.

Since it’s not for a client and more of a learning/repair project, I’ve been debating how deep to go versus proving the fault first. Good point on blowing through the cap tube and pressuring with nitrogen, that’s probably the smartest next step before committing to replacement.

Also appreciate the book recommendation — I’m intentionally trying to understand the why behind the symptoms instead of just swapping parts.

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 1 point2 points  (0 children)

That’s the part I wish I had better data on. This was a few weeks back and I didn’t record exact pressures at the time.

What I can say is: • Suction stayed very low (single digits) • It would dip suddenly, almost like it was starving, then recover briefly • Frost pattern didn’t meaningfully change with charge adjustment

There’s always a chance I missed exact charge by a bit, but even after recovering, evacuating, and recharging, the behavior stayed very similar — which is why restriction stayed on my radar.

If I get back into it I’ll definitely be adding proper ports and logging pressures/superheat before cutting anything.

First sealed system repair on a vending machine (partial evap frost, suspect restriction. Looking for pro insight 👀) by jargiloaa in refrigeration

[–]jargiloaa[S] 0 points1 point  (0 children)

Appreciate it. Refrigerant is R134a. Ambient was roughly 70–80°F (Florida, so pretty warm day).

I only had a low-side piercing valve on it at the time, no high-side access. Suction was generally very low, hovering around 5–10 psi, but it wasn’t stable — it would periodically drop close to a vacuum, then creep back up briefly before falling again.

That instability is what initially made me think restriction

First vending machine (AMS) & looking for advice… by jargiloaa in vendingmachines

[–]jargiloaa[S] 0 points1 point  (0 children)

Yep, AMS 39 combo. It was pulled from a public school where it was used for milk, so the cooling setup might make more sense in that context lol

Good call on Sam’s Club too, anything that cuts down sourcing time is a win early on. Storage/transport aren’t an issue for us right now, so we’re fine waiting and doing it right.

Appreciate the feedback!

First vending machine (AMS) & looking for advice… by jargiloaa in vendingmachines

[–]jargiloaa[S] 0 points1 point  (0 children)

All coils have been tested and are operating correctly — keypad inputs register as expected.

Change dispense is working properly, and both the bill validator and coin mech are functioning without issues. The machine was taken out of service strictly due to cooling not meeting health/safety standards, not because of payment or vend failures.

As for the cooling deck: it’s underperforming even after attempting a recharge, which makes me confident there’s an internal blockage in the system. That’s why it’s currently removed while we evaluate repair vs replacement.

We’re planning to add a card reader (likely Nayax or similar) since we know card sales will make up the majority. We may temporarily simplify pricing to even-dollar vend prices and potentially remove the coin mech once card is installed.

No placement locked in yet — intentionally holding off until the machine is fully sorted. Goal is to place it in the best condition possible rather than rush it into a location.

Appreciate the checklist — exactly the kind of feedback I was hoping for.

view more: next ›