Ma koliko je pregrevanje jako, napajanje mora biti provereno.

Ma koliko means no matter how much / however much / however.

In this sentence, it introduces a concessive clause: something is true regardless of the degree of the overheating.

So:

• Ma koliko je pregrevanje jako... = No matter how severe the overheating is...

A very close paraphrase would be:

• Bez obzira na to koliko je pregrevanje jako... = Regardless of how severe the overheating is...

Because je is a clitic in Serbian, and clitics usually go in second position in their clause.

Here the subordinate clause is:

• Ma koliko je pregrevanje jako

The opening unit ma koliko counts as the first element, so je comes right after it.

This word order is very typical in Serbian. English speakers often expect something more like ma koliko pregrevanje je jako, but that would not be the normal Serbian placement.

Here jako is not the adverb very. It is the neuter singular form of the adjective jak (strong, severe, intense).

It agrees with pregrevanje, which is a neuter singular noun.

So:

• jak = masculine singular
• jaka = feminine singular
• jako = neuter singular

Because pregrevanje is neuter, Serbian uses:

• pregrevanje je jako = the overheating is severe/intense

This happens to look identical to the adverb jako (very), which is why it can be confusing.

Pregrevanje is a neuter noun meaning overheating.

It is a noun formed from a verb, so it works a bit like an English verbal noun or gerund-like technical noun:

• pregrevati / pregrejati = to overheat
• pregrevanje = overheating

In this sentence, it is in the nominative singular because it is the subject of je jako:

• pregrevanje je jako = the overheating is severe

Many Serbian technical nouns ending in -nje are neuter and behave like this.

Napajanje can mean a few related things depending on context:

• power supply
• power source
• powering / supply of power

In a technical sentence like this, it most likely means the power supply.

Grammatically, it is also a neuter singular noun, which matters because provereno has to agree with it.

This is a standard way to say must be checked in Serbian.

It breaks down like this:

• mora = must
• biti = be
• provereno = checked

So:

• napajanje mora biti provereno = the power supply must be checked

This is basically a passive construction.

A very similar alternative is:

• napajanje mora da bude provereno

That means the same thing. Serbian often allows both:

• morati + infinitive
• morati da + present form

Because provereno agrees with napajanje, which is neuter singular.

The form proveren / proverena / provereno is a passive participle from proveriti (to check), and it changes like an adjective:

• proveren = masculine singular
• proverena = feminine singular
• provereno = neuter singular

Since the noun is:

• napajanje = neuter singular

the correct form is:

• napajanje mora biti provereno

If the noun were feminine, for example baterija, you would say:

• Baterija mora biti proverena.

Yes. The main clause is in the passive voice:

• napajanje mora biti provereno = the power supply must be checked

The focus is on what needs to happen to the power supply, not on who performs the checking.

A more active version would be something like:

• Serviser mora proveriti napajanje. = The technician must check the power supply.

Serbian also very often uses an impersonal/reflexive alternative:

• Napajanje se mora proveriti.

That is also very common and natural in instructions or technical writing.

The comma separates the introductory subordinate clause from the main clause.

Structure:

• Ma koliko je pregrevanje jako, = subordinate concessive clause
• napajanje mora biti provereno. = main clause

This is similar to English punctuation:

• No matter how severe the overheating is, the power supply must be checked.

So the comma is expected here.

Yes, Serbian word order is fairly flexible, but not every rearrangement sounds equally natural.

For example, this is possible:

• Napajanje mora biti provereno, ma koliko je pregrevanje jako.

That keeps the meaning, but the emphasis changes slightly because the main point comes first.

However, you cannot move words around completely freely. In particular:

• ma koliko should stay together
• the clitic je still wants second position in its clause

So Serbian word order is flexible, but it still follows important placement rules.

It is understandable and grammatically acceptable, especially in technical context.

That said, Serbian speakers might also say it in other ways that can sound a bit more natural or more formal, for example:

• Bez obzira na to koliko je pregrevanje jako, napajanje mora biti provereno.
• Ma koliko jako bilo pregrevanje, napajanje mora biti provereno.
• Napajanje se mora proveriti bez obzira na jačinu pregrevanja.

So the given sentence is fine, but Serbian offers several natural alternatives depending on style:

• technical/instructional
• formal
• more explicit

It has two parts:

1. Ma koliko je pregrevanje jako

   • subordinate concessive clause
   • says that the degree of overheating does not change the result

2. napajanje mora biti provereno

   • main clause
   • states the required action

So the logic is:

• Even if the overheating is very severe, the power supply still has to be checked.
• The necessity of checking does not depend on the intensity of the overheating.

That is the key grammar pattern behind the sentence.