Котельная уже работает.

Котельная usually means a boiler room, boiler house, or heating plant, depending on context.

In everyday Russian, it often refers not just to a physical room, but to the whole boiler/heating facility as a unit. So in this sentence, it most naturally means that the boiler/heating system is already in operation.

It does not usually mean an ordinary room with a random boiler in it in a very literal English sense unless the context makes that clear.

Because котельная and котёл are different things:

• котёл = a boiler or cauldron (the machine/container itself)
• котельная = the boiler room / boiler house / heating facility where the boiler equipment operates

So Котельная уже работает means the facility/system is operating, not just one individual boiler.

Russian normally does not use a present-tense form of to be in sentences like this.

So:

• Котельная уже работает. literally looks like
• Boiler house already works / is operating.

This is completely normal in Russian. You do not need a separate word for is here.

Работает comes from работать, which usually means to work.

But in this context, it is better understood as:

• is operating
• is functioning
• is running

For machinery, services, systems, businesses, and facilities, работать is very commonly used in this broader sense.

So here it does not mean the boiler room is doing a job; it means it is in operation.

Because the subject, котельная, is singular.

Russian verbs in the present tense agree with the subject:

• котельная работает = the boiler house works/is operating
• котельные работают = the boiler houses work/are operating

Also, котельная is grammatically feminine, but in the present tense singular, the form работает is the same for masculine, feminine, and neuter subjects.

It is in the nominative case because it is the subject of the sentence.

The basic structure is:

• Котельная = subject
• уже = adverb
• работает = verb

So the sentence is built like [Subject] + [already] + [is operating].

If котельная were an object in another sentence, its form might change depending on the case.

Уже usually means already, and that is the best translation here.

In this sentence, it suggests that the boiler/heating facility has started functioning by now, perhaps earlier than expected or at least by this point in time.

Depending on context, уже can also add a nuance like:

• by now
• at this point
• now already

So Котельная уже работает can imply:

• it wasn’t operating before, but now it is
• someone was waiting for it to start
• the heating season or system has begun

Yes. Russian word order is flexible, although the neutral order here is very natural:

• Котельная уже работает.

Other orders are possible, for example:

• Уже работает котельная.
• Котельная работает уже.

These can sound different in emphasis. For example:

• Котельная уже работает. = neutral statement
• Уже работает котельная. = emphasizes already
• Котельная работает уже. = possible, but more context-dependent and less neutral on its own

So the original sentence is a very standard and natural way to say it.

Because the sentence describes the current state: the boiler facility is now operating.

Russian could also use a verb meaning started working, such as:

• Котельная уже заработала.

That would focus more on the moment of starting up:

• has already started working
• has already come online

By contrast:

• Котельная уже работает focuses on the fact that it is currently running

So both can be correct, but they highlight slightly different things.

Normally, it means the system/facility is functioning, not that the staff are at work.

For people working there, Russian would usually make that clearer with other wording, for example by referring to workers, employees, or operators.

So a native speaker would most naturally understand:

• the boiler room/heating plant is up and running

not:

• the workers in the boiler room are already on duty

The stress is on the second syllable:

• коте́льная

A rough pronunciation guide:

• ka-TYEL-na-ya

A few helpful points:

• е after a soft consonant sounds like ye
• льн is a soft consonant cluster, which may feel unfamiliar to English speakers
• the ending -ая is common in feminine adjectives and adjective-based nouns

Since котельная historically comes from an adjective-type form, its ending may look familiar if you have seen words like столовая or приёмная used as nouns.

In this sentence, it functions as a noun.

Its form looks like a feminine adjective, and historically it comes from that kind of pattern. Russian often turns adjective forms into nouns when the meaning is understood from context.

Compare similar words:

• столовая = dining room / cafeteria
• приёмная = reception room / office
• котельная = boiler room / boiler house

So even though it looks adjective-like, here you should learn it as a regular vocabulary word meaning a place/facility.

That is more literal word-for-word, but it sounds unnatural in English.

Better English translations would be:

• The boiler room is already operating.
• The boiler house is already running.
• The heating plant is already working.

So while works helps show the Russian structure, is operating or is running is usually the best natural English rendering.