GMCC KSM125V2VFTL Rotary Compressor: 12.5 cm3, One GX Column, and the Generation Digit That Changes the Part Number

By the Qishanr technical desk. Reviewed 2 November 2026.

Key facts at a glance

Three checks make the row usable. 3835 divided by 905 is 4.238, which the row prints as 4.24. 3835 multiplied by 3.412 is 13086 Btu/h against the printed 13085, a one-unit rounding. And 12.5 multiplied by 50 gives 625 cm3 of swept volume per second, which is the number this article uses to compare it with its neighbours.

Everything in the table above belongs to one row. Nothing in it belongs to the model name alone, because the same page prints a second column whose rows carry the same refrigerant, the same voltage and a different test condition. That distinction is the first thing a buyer has to get right, and it is the subject of the third section.

What does the model string fix, and what does it leave open?

The manual's naming page sets out the string position by position, and this model reads as follows.

- K is the refrigerant position, printed in the legend as R32 and R410A together. The column heading above the row narrows it to R32.

- S is the structure position, printed as single cylinder.

- M is the series name. The page groups these rows under the label SM, which is the same letter.

- 125 is the displacement field. The legend prints this field as cm3/rev multiplied by ten, so 125 reads as the 12.5 class, and the row prints 12.5 exactly.

- V in the fifth position is the supply code, printed in the legend as single phase, 50 Hz, 220/230/240 V.

- The digit after that letter, here 2, distinguishes builds inside that supply. The legend does not give the digits separate meanings, so the only safe reading is that V1, V2 and V05 are different builds on the same supply, which the rows themselves demonstrate.

- The next V is the motor specification, printed as low load type, high efficiency.

- FTL is a build suffix. The legend does not decode it, and neither does any other page of the manual that was read for this article.

Two things follow. First, the string fixes the refrigerant, the cylinder count, the supply and the motor class, and it fixes the displacement to the tenth. Second, it leaves the trailing suffix undefined, which is where the generation digit does its work: V1VFT and V2VFTL are two different part numbers, and the catalogue prints only the second one at 12.5.

The string carries no leading duty letter. The legend reserves that position for heat pump, freezing and cold storage, heating, and cabinet air conditioning, and prints the undivided case as compressors for air conditioning. This row has no such letter, so the catalogue classifies it as an air-conditioning compressor, and the section heading confirms it: the page is titled green refrigerant compressor in English and air-conditioning compressor in Chinese.

That point needs stating plainly because this model is often described as a refrigeration compressor. Nothing in the manufacturer row supports a freezing or cold-storage duty: there is no leading L, the refrigerant is R32 rather than a low-temperature refrigerant, and the test condition is the air-conditioning one. A supplier page that lists AC, drier, refrigeration and chiller in one line is repeating a standard string rather than making four separate ratings.

Why does one page print two columns, and which one is this row in?

The page that carries this row is laid out in two columns, and the two headings are not the same. The left column prints R32, single phase 50 Hz 220/240 V, and Test Condition: G X. The right column prints the same refrigerant and the same supply, and Test Condition: ARI.

That single word changes every number under it. The clearest demonstration is a displacement that both columns print, 18.0 cm3/rev:

Read the 18.0 pair across the column break and the same displacement appears to lose 16.2 per cent of its capacity while drawing 19.3 per cent more input. Read the 19 cm3 pair and the same thing happens again, at 16.9 per cent and 21.9 per cent. It is not a defect in the catalogue. It is two different rating conditions printed side by side.

There is a second difference, and it makes the comparison worse rather than better. Every row in the ARI column was read at a U motor class, and every row in the GX column at a V class. So the column break and the build letter move together, and no arithmetic can separate them. Any claim of the form this build is more efficient than that build, when the two rows sit in different columns, is unsupported by this table.

The practical rule is short: this model is a GX row. Its 3835 W and its 4.24 belong to GX at 220/240 V, 50 Hz, single phase, on R32. Neither figure can be carried to an ARI row, and no ARI figure can be carried back. The ARI column on this page runs 2.70 to 3.02 on coefficient of performance; the GX column runs 3.53 to 4.40. A buyer who quotes 4.24 next to an ARI number is comparing a high-efficiency build at the milder condition with a standard build at the harsher one.

What does the GX column print around 12.5, and where does this row sit?

Ten rows in the SM family sit in the same GX column. Read together they form a ladder, and the target row is the eighth step:

Three readings matter for selection.

Capacity per cubic centimetre rises towards the top of the ladder. At 9.7 cm3/rev the row makes 2905 W, which is 299.5 W per cm3. At 12.5 it makes 3835 W, which is 306.8 W per cm3. At 13.3 it reaches 307.5. The middle of the ladder, around 10.3 cm3, is the low point at 297.6. So the 12.5 slot is not a stretched small machine; it sits where the family is working hardest per unit of displacement.

The step above it is 650 W wide. From 11.3 to 12.5 the capacity moves 3440 to 3835 W, and from 12.5 to 13.3 it moves to 4090 W. The increments are 395 W and 255 W. A designer choosing between three adjacent slots has a narrower gap above 12.5 than below it, which is why this is usually the last step before a system redesign rather than the first.

The capacitor and the discharge bore move in steps, not continuously. 25/370 covers 8.5 through 10.6 cm3. The 35/370 capacitor appears first at 11.3 and stays through 13.3, except for one 40/370 row at 13.3. This model is therefore inside the 35/370 group, sharing the run capacitor with both of its neighbours, which matters when a replacement is being sourced from stock.

Why does the discharge bore track the efficiency band?

Sort the same ten rows by the printed discharge line and the efficiency separates cleanly:

Every row with a 12.9 mm discharge prints a coefficient of performance of 4.22 or better; every row with a 9.8 mm discharge prints 4.18 or lower. The 12.9 group is also tighter: 4.22 to 4.25 across a displacement span of 10.3 to 13.3 cm3, where the 9.8 group spreads from 4.02 to 4.18 over a span of only 8.5 to 9.7.

The physical reading is straightforward and does not need a claim about causation. A larger discharge bore lowers the pressure drop on the high side, and the rows that carry it are the ones the manufacturer prints at the higher efficiency. The catalogue does not say that the bore causes the efficiency, and this article does not either. What the table does support is a selection rule: if a system is being matched to 12.9 mm pipework, the whole 10.3 to 13.3 cm3 block is available without changing the line size, and this model sits inside that block.

Input power per unit of swept volume is the check that the rule is not an artefact of capacity. The target row draws 905 W for 625 cm3 of swept volume per second, which is 1.448 W per cm3. The 10.3 cm3 row draws 1.408, the 11.3 row 1.443, the 13.3 rows 1.447 and 1.459. Those five numbers sit inside a band of about 3.6 per cent, which is what a common platform looks like. The 8.5 and 9.2 cm3 rows, at 1.518 and 1.517, do not.

Is there a V1 build at 12.5, and what changes with the generation digit?

The 2024 edition prints exactly one row at 12.5 cm3/rev, and it is the V2 build. A search of the full table text returns no other line with 12.5 in the displacement column, in any band.

The supplier's own product page, however, sells the V1 build at the same displacement:

The two documents agree on the displacement to the tenth and disagree by 25 W on capacity and 5 W on input, which is 0.7 per cent and 0.6 per cent. The supplier figure is internally consistent, since 3810 divided by 900 is 4.233 and the page prints 4.23.

Two cautions apply. The product page does not print a test condition, so the 25 W gap cannot be attributed to the generation digit alone; the page could be quoting GX, or a rounded version of it. And the part number does not change by one character: the supply digit moves from 1 to 2 and the suffix gains an L, from VFT to VFTL. A purchase order that names the family and the displacement, without the full string, will not distinguish these two.

That is the practical meaning of the generation digit at this displacement. It is not a new performance level. It is a build revision whose output moved by less than one per cent, and whose part number moved in two places at once.

The 13.3 slot shows the same thing with two rows side by side in one column. KSM133V2VFTL prints 4090 W at 970 W for a coefficient of performance of 4.22, on a 40/370 capacitor. KSM135V1VFT prints 4085 W at 962 W for 4.25, on a 35/370 capacitor. Capacity differs by 5 W, input by 8 W, and the run capacitor by 5 microfarad. The two are the same size, nearly the same output, and not interchangeable, because the capacitor in the control box is not.

What do the supplier pages print, and where do those numbers come from?

One supplier page does not survive the comparison, and it is worth showing why, because it is the page a buyer will land on when searching for the larger sibling.

The four numbers on the product page, 3025 W, 10321 Btu/h, 1050 W and 2.88, are not a rounding of the manual's 13.3 row. They are a different row of the same catalogue, printed against a 12.0 cm3 model in the ARI column. The same four numbers also appear in two distributor-hosted editions of this catalogue against a third model string at 13.3 cm3, which means the set has been attached to at least three different designations across the documents reviewed.

None of this makes the page useless. It makes it a catalogue of stock rather than a rating sheet. The 3025 W figure is real, printed by the manufacturer, and belongs to a 12.0 cm3 build at the ARI condition. Read against the GX row for the same string it understates capacity by 26 per cent and overstates input by 9.1 per cent, and the coefficient of performance falls from 4.25 to 2.88, which is where the error becomes visible to anyone who checks the arithmetic.

Two further strings appear on the supplier site but not in the 2024 edition: an 11.3 cm3 build, KSM113V4VEZ, and a 12.0 cm3 build, KSM120V2UFT. Neither has a printed row in the manual that this article was read from, so neither is quoted here with numbers. That is the ordinary condition of a catalogue that lists what is in stock while the manual lists what has been rated, and it is the reason the row and its heading are treated as the unit of evidence throughout this page.

The smaller sibling page behaves better. Its 8.9 cm3 model prints 2665 W at 635 W for a coefficient of performance of 4.20, and the manual's nearest GX row, a V05 build at the same displacement, prints 2690 W at 672 W for 4.02. Capacity is 25 W apart, input 37 W apart, and the coefficient of performance differs by 0.18 in the opposite direction from the 12.5 pair, which is a reminder that these pages are separate statements rather than one table with parts missing.

What does the row print, and what does it not?

The eight missing fields are the same ones missing from every row on the page, so their absence is a property of the catalogue rather than of this model. The consequence for a buyer is narrow and worth stating: the row is enough to size a system and to order a compressor, and it is not enough to design the electrical protection, the mounting or the acoustic treatment.

What duty does this row belong to?

The catalogue gives no application list for any row. The duty has to be read from three printed things: the absence of a leading duty letter, the refrigerant position, and the column heading.

All three point the same way. No leading letter means air-conditioning duty. K covers R32 and R410A, and the heading narrows it to R32. GX is the air-conditioning test condition used across this page. The result is a single-phase R32 air-conditioning compressor at 12.5 cm3/rev, in the size class of a residential split or the upper end of a multi-split system.

Capacity translates to about 1.09 refrigeration tons at 12,000 Btu/h per ton, which is a conversion for sizing conversations and not a rating. The catalogue prints no tonnage and no horsepower for any KS row, so any horsepower figure attached to this model is a trade label.

What the row cannot tell you is which equipment it is approved in. No row on the page carries an approved-equipment list, and the front matter of the manual states that the data is for reference only and that the actual data is subject to the latest specification document. A requirement written as 12.5 cm3, R32, 220/240 V, GX, 3835 W is defensible; a requirement written as three and a half horsepower is not.

How should a buyer specify this model?

The order matters because the first two steps are the ones buyers skip. Starting from capacity leads to a 3835 W search that returns ARI rows in the same range, and the resulting comparison mixes conditions. Starting from the string and the column makes the capacity a consequence rather than a filter.

Where can this row be checked?

Four documents and four pages cover this article, and they do different jobs.

The primary document is the 2024 edition of the manufacturer's rotary compressor manual, which is where the row, both column headings, the naming page and every figure above come from. The official entry point for the current edition is the downloads page on the manufacturer site, and a distributor-hosted copy of the 2024 manual is the file this page was read from, byte for byte identical at 2,990,900 bytes. The manufacturer's product centre gives the family positioning for the SM series without repeating the row data.

On the supplier side, the GMCC rotary compressor range page is the category entry for this family, the wider rotary compressor category page covers the platform it belongs to, and the GMCC scroll line is the adjacent technology a buyer usually compares against when the capacity requirement grows. The R410A example on the blog side shows how the same catalogue reads when the refrigerant letter is not K, which is a useful contrast when ordering across platforms.

The two administrative pages age fastest. The news index carries edition changes to the manual, and any capacity figure quoted here should be re-read there before it is written into a purchase order.

Which standards and approvals frame the purchase?

Three documents sit outside the catalogue and shape a purchase of this row.

The safety side of a motor-compressor is governed by the IEC 60335 household appliance safety series, of which IEC 60335-2-34 is the part written for motor-compressors. That is the standard a test house cites when it certifies the component, and it is the reason approval marks matter even though this catalogue prints none.

The refrigerant side is a commercial constraint before it is an engineering one. R32 is a single-component refrigerant rather than a blend, so it does not fractionate and does not carry the top-up rules that apply to blends, which is one reason it holds its place in residential air conditioning. Refrigerant supply and handling in the European market are governed by Regulation (EU) 2024/573, which is where a buyer confirms obligations rather than in a compressor catalogue. The designation and safety classification of the refrigerant belong to the designation standard, not to this table.

The demand side explains why a family keeps ten rows inside 8.5 to 13.3 cm3. The IEA's The Future of Cooling sets out how much of the growth in electricity use comes from air conditioning in warm markets, and every efficiency point in a row like this is multiplied by that volume.

Against all three, the catalogue's own sentence still governs the numbers: reference only, subject to the latest specification document.

Frequently asked questions

What is the cooling capacity of the KSM125V2VFTL?

3835 W, printed as 13085 Btu/h, at the GX test condition on single-phase 50 Hz 220/240 V with R32. The figure belongs to that column heading and does not transfer to the ARI column printed beside it.

Is 125 the displacement?

Yes, as a code. The legend prints the displacement field as cm3/rev multiplied by ten, so 125 reads as the 12.5 class, and this row prints 12.5 exactly. The code and the printed value agree here, which is not true of every row in the manual.

Is it a 50 Hz or a 60 Hz compressor?

50 Hz, single phase, 220/240 V. The 60 Hz family is a separate set of rows with N in the supply position, and those rows print different capacities at the same displacement.

What refrigerant does it use?

R32. The K in the first position covers R32 and R410A together, so the letter alone does not decide between them; the section heading above the row does.

Is it a refrigeration compressor?

Not according to the manual. There is no leading duty letter, the refrigerant is R32, and the test condition is the air-conditioning one. The legend uses a leading L for freezing and cold storage, and this string has none. A supplier page that lists AC, drier, refrigeration and chiller in one line is repeating a standard string rather than making four ratings.

Why do two rows on the same page print different COPs at the same displacement?

Because the page prints two columns. The left column is rated at GX, the right at ARI, and every row in the right column also carries a U motor class. The column break and the build letter move together, so the difference cannot be attributed to either one alone.

Can I substitute KSM125V1VFT for this model?

Only with a documented decision. The two print the same 12.5 cm3/rev and differ by 25 W on capacity and 5 W on input, but the supply digit changes from 1 to 2 and the suffix gains an L. The V1 figure is also a supplier statement that prints no test condition, so the gap cannot be assigned to the generation alone.

What capacitor does it need?

35/370. The 11.3 and 13.3 neighbours share it, while the 13.3 V2 row prints 40/370 and the 8.5 to 10.6 rows print 25/370. The capacitor is one more field that has to be read from the row rather than carried across the family.

Does this row get revised?

The front matter states the rule: the data is for reference only and the actual data is subject to the latest specification document. Rows do change between editions, and the news index is where a new edition is recorded. Any figure from this page should be re-read there before it enters a purchase order.

Sources