Learn about the Compressor

The same inspection process should be followed, including checking the filter screen, cooling fans, operating mode, and refrigeration parameters.

Another important point to note is that if the temperature is set too low, the evaporator may freeze. When this happens, it can restrict proper airflow and prevent the machine from cooling effectively.

These factors can contribute to compressor issues or damage, even if the machine is less than one year old.

Upon Inspection:

Loud Noise = it may be a problem with the compressor.

Note:

• Condensation on the evaporator can cause oxidation and holes in the copper or aluminum pipes or weld joints over time.

• This can even at anytime from few months (less than a year) to few years

R290 = Propane (high-purity refrigerant grade) used in modern cooling equipment.

• Type: Refrigerant gas

• Chemical: Propane (C₃H₈)

• Charge amount: 80 grams

• Used in: New vending machines, refrigerators, display coolers, freezers

R290 has largely replaced R134a in new equipment, especially in the EU.

• Very energy-efficient

• Environmentally friendly (very low global warming impact)

• Excellent cooling performance

• Required by newer environmental regulations

⚠️ The trade-off: it is flammable

The refrigeration cycle is identical — only the gas is different.

• Compressor — pumps the refrigerant

• Condenser — releases heat outside

• Expansion device — lowers pressure

• Evaporator — absorbs heat inside (creates cold)

👉 R290 is the fluid circulating through these parts.

That’s the exact amount of refrigerant charge inside the sealed system.

• Very small quantity

• Precisely measured at the factory

• Important for correct cooling performance

Small hydrocarbon charges (like 80 g) are standard for vending machines.

Your machine contains BOTH:

• Compressor → mechanical pump (metal component)

• R290 (80 g) → refrigerant gas inside the system

⚠️ Important safety note (EU)

Because R290 is propane:

• Do NOT puncture refrigeration lines

• Do NOT use open flames near leaks

• Only certified technicians should service or recharge

R134a is a chemical gas used in cooling systems to absorb heat and produce cold. In vending machines, it circulates through the sealed refrigeration circuit to keep drinks or food chilled.

• Type: Refrigerant (cooling fluid)

• Chemical name: 1,1,1,2-Tetrafluoroethane

• Common uses: Vending machines, refrigerators, car A/C systems, small commercial coolers

It is not a mechanical part.

• Not a compressor

• Not a motor

• Not a pump

Type: Synthetic chemical (HFC)

Pros

• Non-flammable (safer to handle)

• Stable and widely used for decades

• Easy servicing

Cons

• High environmental impact (greenhouse gas)

• Being phased out in the EU

• Slightly less energy-efficient than newer options

Think of the refrigeration system as a loop with different components:

1. Compressor — squeezes the refrigerant gas (raises pressure & temperature)

2. Condenser — releases heat to the outside air

3. Expansion device — drops pressure

4. Evaporator — absorbs heat inside the cabinet (creates cooling)

👉 R134a is the fluid flowing through all these parts.

🔧 Simple analogy

• Compressor = heart (pumps the system)

• R134a = blood (carries heat around the system)

The compressor is the heart of the cooling system. When it starts dying, the machine will warn you — if you know what to look for.

1) Unusual noises (early warning)

Normal: soft humming

Bad signs:

• Loud buzzing or growling

• Clicking on/off repeatedly

• Knocking or rattling

• Sudden increase in noise

👉 Clicking every few seconds often means hard starting or internal failure

2) Poor cooling or temperature rising

Symptoms:

• Drinks not cold enough

• Temperature slowly creeping up

• Machine runs constantly but doesn’t cool

• Previously cold items now lukewarm

⚠️ Could also be low refrigerant — but compressor is a major suspect.

3) Short cycling (starts and stops rapidly)

The compressor:

• Starts

• Runs a few seconds or minutes

• Stops

• Repeats over and over

Common causes:

• Overheating

• Internal wear

• Electrical problems

• Failing start relay

This behavior destroys compressors quickly.

🥵 4) Very hot compressor housing

Warm is normal. Too hot to touch = problem.

Overheating causes:

• Dirty condenser coils

• Poor ventilation

• Internal mechanical wear

• Electrical issues

5) Higher electricity use

If your power bill rises but sales don’t:

👉 The compressor may be running constantly trying to keep up

6) Compressor hums but won’t start

You may hear:

• Loud hum

• Then a click

• Then silence

• Repeats every minute or so

Often indicates:

⚠️ Locked rotor (mechanical seizure)
⚠️ Failed start capacitor/relay
⚠️ Compressor at end of life

Signs of imminent failure (call technician ASAP)

• Burning smell

• Tripping breaker or blowing fuse

• Machine completely warm

• Compressor silent when it should run

• Oil residue around compressor or tubing

🏆 Expert tip for R290 machines

Because R290 systems are efficient, compressors often fail due to:

👉 Overheating from dust or poor airflow — NOT the refrigerant itself

Cleaning the condenser regularly is the #1 way to prevent failure.

Typical symptoms

✅ Compressor runs continuously (never rests)
✅ Cooling weak or gradually getting worse
✅ Inside may be cool but not cold
✅ Partial frost on evaporator (only one corner/section)
✅ Oily residue on copper tubing joints
✅ No unusual compressor noise

👉 Refrigerant carries oil — leaks often leave oily spots.

What’s happening

Not enough refrigerant to absorb heat → system runs but can’t reach temperature.

Typical symptoms

❌ Loud buzzing, clicking, or knocking
❌ Compressor tries to start then stops
❌ Very hot compressor shell
❌ Breaker trips or lights dim on startup
❌ Machine not cooling at all
❌ Compressor silent when it should run

👉 Often sudden failure (worked yesterday, warm today)

🔎 QUICK DIY CHECKS (safe for non-technicians)

✅ 1) Listen test

• Smooth steady hum → likely leak or airflow issue

• Loud buzz + click → compressor/start problem

✅ 2) Touch test (carefully)

Back/bottom of machine:

• Warm condenser pipes → compressor is pumping

• Completely cool → compressor not working

⚠️ Hot is normal — burning hot is not.

✅ 3) Runtime behavior

Compressor never stops? → Leak likely
Starts/stops every few seconds? → Compressor issue

✅ 4) Cooling history

• Gradual decline over weeks/months → Leak

• Sudden failure overnight → Compressor/electrical

⚠️ Special note for R290 machines

R290 (propane) systems:

• Use small refrigerant charge (like your 80 g)

• Even a tiny leak can kill cooling

• Repairs MUST be done by certified technicians (flammable gas)

Which is worse?

Compressor failure = usually more expensive

• Leak repair + recharge: moderate cost

• Compressor replacement: high cost

But small R290 systems are often repairable.

What about R134a systems? (Compared to R290)

R134a machines are much less restrictive and less hazardous to service.

👉 Key difference: R134a is NOT flammable

✅ Refrigerant charge size

R134a systems usually contain much more refrigerant than R290 systems.

• Small vending machine: ~120–300 g (sometimes more)

• Your R290 machine: only 80 g

👉 Result:

R134a leaks are often slower and less catastrophic

• Machine may still cool for weeks/months

• Performance gradually declines

• Easier to diagnose early

🔥 Safety

R134a

✅ Non-flammable
✅ Non-explosive

⚠️ Still not harmless (can displace oxygen in confined spaces)

R290

⚠️ Flammable propane
⚠️ Ignition risk if leaked
⚠️ Strict safety procedures required

🧰 Who can repair it?

R134a systems

Repairs are easier legally and technically.

In the EU/Spain:

• Technician must be F-Gas certified to handle refrigerant professionally

• But no explosion risk procedures needed

• Widely serviced everywhere

👉 Many older repair shops are very comfortable with R134a.

R290 systems

Stricter handling rules because of flammability:

• Explosion-safe tools required

• No sparks or open flames

• Special recovery procedures

• Training for hydrocarbons

Real-world example

Small leak in R134a vending machine

• Drinks slightly less cold

• Compressor runs longer

• Can operate for a long time before failure

Same leak in R290 machine

• Cooling may collapse quickly

• Cabinet warms noticeably

• System can stop performing within days

Expert bottom line

👉 R134a = safer and more forgiving ( models below 2024)
👉 R290 = more efficient but less tolerant of leaks ( models 2024 and up )