Domofon nie działa od rana, więc każdy lokator musi iść na parter i otwierać drzwi gościom.

Domofon means intercom or entry phone in a building, especially the system people use to let visitors in.

In this sentence, it refers to the building’s door-entry system.

A few related words:

• domofon = intercom / entry phone
• wideodomofon = video intercom
• drzwi wejściowe = entrance door

So Domofon nie działa means The intercom isn’t working.

Działać means to work / to function / to operate.

So:

• działa = it works / it is working
• nie działa = it doesn’t work / it isn’t working

The subject is domofon, which is a singular masculine noun, so the verb takes the 3rd person singular form:

• domofon działa
• domofon nie działa

Polish often uses the simple present where English might use either doesn’t work or isn’t working, depending on context.

Od rana means since the morning or more naturally since this morning / all morning since early morning.

Literally:

• od = from / since
• rana = genitive form of rano-related expression meaning morning

In time expressions, od often marks the starting point:

• od rana = since morning
• od wczoraj = since yesterday
• od poniedziałku = since Monday

So Domofon nie działa od rana means the problem started in the morning and is still continuing.

Więc means so, therefore, or thus.

It links the first part of the sentence to the consequence:

• Domofon nie działa od rana, więc...
• The intercom has not been working since morning, so...

It is similar to:

• dlatego = therefore / that’s why
• więc = so

Often:

• ..., więc każdy lokator musi...
• ..., dlatego każdy lokator musi...

Both work, though więc feels especially natural in everyday speech.

Każdy lokator means each tenant / every tenant.

Polish uses każdy + singular noun, not plural:

• każdy lokator = each tenant
• not każdy lokatorzy

Compare:

• każdy lokator musi = each tenant has to
• wszyscy lokatorzy muszą = all the tenants have to

Both are possible in real life, but they mean slightly different things:

• każdy lokator focuses on each individual
• wszyscy lokatorzy focuses on the whole group

Musi means must / has to. It is a modal verb, and modal verbs are followed by an infinitive.

So:

• musi iść = must go
• musi otwierać = must open / has to keep opening

Breakdown:

• musieć = to have to / must
• musi = he/she/it must
• iść = to go
• otwierać = to open

This is very similar to English:

• must go
• has to open

This is a very common question, because Polish has two important verbs for to go on foot:

• iść = to go, to be going, one specific trip / movement in one direction
• chodzić = to go habitually, repeatedly, or in various directions

Here, musi iść na parter means has to go down to the ground floor in a concrete situation.

Why not chodzić? Because the sentence is about a practical action required by the broken intercom, not a habitual pastime.

Compare:

• Muszę iść do sklepu. = I have to go to the shop.
• Chodzę do sklepu codziennie. = I go to the shop every day.

So iść is the natural choice for a specific trip.

In Polish, floor levels are often expressed with na.

So:

• na parter = to the ground floor
• na pierwsze piętro = to the first floor

This is one of those patterns you mostly just learn as a unit.

Also, there is an important motion vs location contrast:

• na parter = to the ground floor, movement toward it
• na parterze = on the ground floor, location

So:

• iść na parter = go down to the ground floor
• być na parterze = be on the ground floor

Here there is movement, so na parter is correct.

This is about aspect, one of the most important parts of Polish verbs.

• otwierać = imperfective
• otworzyć = perfective

Very roughly:

• imperfective focuses on the process, repetition, or ongoing action
• perfective focuses on a completed single action

In this sentence, otwierać drzwi gościom suggests repeated action: each tenant may have to go downstairs and open the door for visitors whenever needed.

So otwierać fits the idea of:

• repeated action
• general duty
• not just one single completed opening

If you said otworzyć, it would sound more like one complete act:

• musi iść na parter i otworzyć drzwi gościom = must go downstairs and open the door for the guests

That version is also grammatically possible, but it slightly changes the focus.

Because Polish uses the pattern:

otwierać komuś drzwi = to open the door for someone

Here:

• drzwi = the door
• gościom = to/for the guests

Gościom is the dative plural of goście:

• nominative plural: goście = guests
• dative plural: gościom = to/for the guests

So the structure is:

• otwierać drzwi gościom
• literally: open the door to the guests
• naturally: open the door for guests

This is very normal Polish usage.

In Polish, drzwi is a plural-only noun. Even when English would say door in the singular, Polish usually says drzwi.

So:

• te drzwi = this door / these doors, depending on context
• otworzyć drzwi = open the door

This is just how the noun works in Polish.

Other plural-only nouns exist too, but drzwi is one of the most common ones learners meet early.

Because Polish has no articles. There is no direct equivalent of a/an/the used the way English uses them.

So:

• domofon can mean the intercom or an intercom, depending on context
• parter can mean the ground floor
• drzwi can mean the door

Context tells you which meaning is intended.

In this sentence, the context clearly points to:

• the intercom
• the ground floor
• the door

because we are talking about a specific building situation.

Yes. Polish word order is more flexible than English, because case endings do a lot of the grammatical work.

The given sentence is very natural:

• Domofon nie działa od rana, więc każdy lokator musi iść na parter i otwierać drzwi gościom.

But other word orders are possible for emphasis, for example:

• Od rana domofon nie działa, więc każdy lokator musi iść na parter i otwierać drzwi gościom.
• Każdy lokator musi więc iść na parter i otwierać drzwi gościom.

The default version sounds clear and neutral.

Lokator means tenant, resident, or occupant, depending on context.

In a building context, it often means a person living there, especially in an apartment building.

Possible related words:

• lokator = tenant / resident
• mieszkaniec = resident, inhabitant
• najemca = tenant in a more legal or contractual sense

Here, lokator sounds natural because the sentence is about people living in the building and dealing with the front door situation.

Because więc introduces a result or consequence, and in standard Polish punctuation it is normally preceded by a comma when it connects clauses.

So:

• Domofon nie działa od rana, więc każdy lokator musi...

The comma helps separate:

1. the problem
2. the consequence

This is very standard and something learners should get used to with connectors like więc, ale, bo, dlatego, depending on structure.