Learn Hardcore Turkish: Şofben çalışmıyor; önce gazın açılması lazım. - The water heater isn’t working; the gas needs to be turned on first.

kombi: a larger unit that heats both water and the house (central heating).
termosifon: a tank-type (often electric) storage water heater. Note: Don’t confuse şofben with şoför (driver).

Is a şofben always gas? The sentence mentions gas.

Commonly, yes; many şofben units are gas-fired, which is why you see gazın açılması. There are also elektrikli şofben models, but if it’s electric you wouldn’t talk about turning on the gas.

How is çalışmıyor formed, and what does it imply?

Root: çalış- (to work/function)
Negative: -mı- (negative vowel-harmonized form of -ma/-me)
Present continuous: -yor So: çalış-mı-yor = “is not working.” It describes a current state: the device isn’t functioning now.

Could I use çalışmaz instead of çalışmıyor?

Çalışmaz means “doesn’t work (generally/habitually)” or “won’t work.” Çalışmıyor is more like “isn’t working (right now).” In this context, çalışmıyor is the natural choice.

What does önce mean here?

Önce means “first”/“firstly” or “before.” In this sentence it means “first.” As a time preposition it pairs with the ablative:

dersten önce = before class Related:
önceden = beforehand/previously
önceki = previous

Why is it gazın, not gazı?

Because the clause is passive and nominalized: gazın açılması literally “the gas’s being opened.” In such clauses, the subject of the passive takes the genitive (gazın).

Passive nominalized: gazın açılması lazım = it’s necessary that the gas be turned on.
Active infinitive: gazı açmak lazım = it’s necessary to turn on the gas (someone must do it).

What exactly is happening morphologically in açılması?

aç-: open/turn on
-ıl-: passive → açıl- “be opened/come on”
-ma: nominalizer → açılma “the opening”
-sı: 3rd person possessive (required in this construction) → açılması “its being opened”

Why use the passive (gazın açılması) instead of the active (gazı açmak)?

Passive makes the sentence impersonal and focuses on the requirement, not on who does it. Both are fine:

Önce gazın açılması lazım. (impersonal)
Önce gazı açmak lazım. (someone needs to do it)

How does lazım work? Can I show who has the obligation?

Lazım expresses necessity with a verbal noun/infinitive.

Impersonal: Gazın açılması lazım. (It needs to be opened.) To show who must act, use a possessive subject on the nominalized verb:
Gazı açmam lazım. = I need to turn on the gas.
Gazı açmamız lazım. = We need to turn on the gas.
Senin gazı açman lazım. = You need to turn on the gas. You can also say:
Gazı açmak zorundayım. (I have to…) — stronger obligation.

What’s the difference between lazım, gerek/gerekiyor, and -malı/-meli?

lazım: common, neutral necessity. Impersonal feel unless you mark the subject (as above).
gerekiyor: “is required/necessary (now)”; slightly more formal: gazın açılması gerekiyor.
gerek: similar to lazım, often written/formal: gazın açılması gerek.
-malı/-meli: “should/ought to”: gazı açmalıyız.
zorunda: strong obligation/compulsion: gazı açmak zorundayız.

Could I say the same thing with gerekiyor?

Yes: Şofben çalışmıyor; önce gazın açılması gerekiyor. Meaning and tone are almost the same; this can sound a bit more formal/explicitly “required.”

Can I make the cause explicit with “because”?

Yes:

Şofben çalışmıyor, çünkü gaz kapalı. (…because the gas is off.)
Şofben çalışmıyor, çünkü önce gazı açmak lazım. Using çünkü is more overtly causal than a semicolon.

Is the semicolon used like in English?

Yes. It neatly links two related independent clauses. A comma is also seen in casual writing, but the semicolon is cleaner here.

How would I say “We first have to turn on the gas”?

Önce gazı açmamız lazım. (Or more forcefully: Önce gazı açmak zorundayız.)

What are the everyday opposites/partners to açmak?

açmak = to turn on/open → adjective: açık (on/open)
kapatmak = to turn off/close → adjective: kapalı (off/closed) So: Gaz kapalı = The gas is off. Gazı açmak = to turn the gas on.

Any quick pronunciation tips for these words?

Şofben: “shof-ben”; ö like French “eu.”
çalışmıyor: “cha-lish-mı-yor”; ı is a back unrounded vowel (no English equivalent).
önce: “oen-jeh”; c is like English “j” in “jam.”