Но через час появилась новая протечка возле батареи, и я снова позвонила диспетчеру.

But an hour later a new leak appeared near the radiator, and I called the dispatcher again.

Breakdown of Но через час появилась новая протечка возле батареи, и я снова позвонила диспетчеру.

• я: I
• новый: new
• и: and
• но: but

Questions & Answers about Но через час появилась новая протечка возле батареи, и я снова позвонила диспетчеру.

Why does the sentence start with Но? Does it always mean but?

Но is a coordinating conjunction meaning but/however. It signals contrast with the previous statement (something changed, a problem returned, etc.). It’s very common at the start of a sentence in Russian, just like But in English.

Why is it через час and not something like после часа?

Через + accusative expresses “after a period of time has passed / in … (time)” → через час = “an hour later / in an hour.”
После часа would more naturally mean “after the hour (as a specific hour/period),” and is less idiomatic for “one hour later” in this context.

What case is час in, and why?

In через час, the noun is in the accusative case because через (meaning “in/after (time)”) governs the accusative.
For an inanimate masculine noun like час, nominative and accusative look the same: час.

Why is the verb появилась feminine?