Der Hausmeister soll morgen die Sicherung austauschen, falls das Problem wieder auftaucht.

The caretaker is said to replace the fuse tomorrow, in case the problem occurs again.

Breakdown of Der Hausmeister soll morgen die Sicherung austauschen, falls das Problem wieder auftaucht.

• morgen: tomorrow
• wieder: again
• falls: in case
• das Problem: the problem
• sollen: to be said to
• der Hausmeister: the caretaker
• die Sicherung: the fuse
• austauschen: to replace
• auftauchen: to occur / to crop up

Questions & Answers about Der Hausmeister soll morgen die Sicherung austauschen, falls das Problem wieder auftaucht.

Why is soll used here, and what does it imply?

soll is the modal verb sollen. In this kind of sentence it often means is supposed to / is to / should in the sense of an instruction, plan, or expectation:

• Der Hausmeister soll ... = The caretaker/janitor is supposed to ...
  It can also sometimes report what someone else says (allegedly), but in this context (a task + time word morgen) it most naturally sounds like a work instruction/plan.

Why is the verb phrase split: soll ... austauschen?

German modal verbs push the “main action” verb into the infinitive at the end of the clause:

• soll = conjugated modal (2nd position in a main clause)
• austauschen = infinitive at the end
  So: Der Hausmeister soll morgen die Sicherung austauschen.

What case is der Hausmeister, and what case is die Sicherung?

• der Hausmeister is nominative (the subject doing the action).
• die Sicherung is accusative (the direct object being replaced).
  The verb austauschen typically takes an accusative object: etwas austauschen.

Does die Sicherung mean a fuse or a circuit breaker?

die Sicherung can mean fuse in general, and in everyday home/electrical contexts it can also refer to a circuit breaker (the thing that “trips”). The exact English choice depends on what kind of installation you’re talking about, but German often uses Sicherung broadly.

Why is morgen placed where it is?

morgen is a time adverb and is very flexible. Here it sits between the modal verb and the object:

• Der Hausmeister soll morgen die Sicherung austauschen.
  That’s a very normal placement. You could also say:
• Morgen soll der Hausmeister die Sicherung austauschen. (more emphasis on tomorrow)

What’s the difference between falls and wenn in this sentence?

falls means in case and suggests the condition is uncertain or just a precaution.
wenn often means if/when and can sound more neutral or even likely/habitual depending on context.
Here, falls das Problem wieder auftaucht = in case the problem shows up again (i.e., only if it happens).

Why is there a comma before falls?

Because falls das Problem wieder auftaucht is a subordinate clause (Nebensatz). German normally separates subordinate clauses from the main clause with a comma:

• ..., falls ...

Why is the verb auftaucht at the end of the falls clause?

In German subordinate clauses introduced by words like falls, the conjugated verb goes to the end:

• falls das Problem wieder auftaucht
  That’s standard subordinate-clause word order.

Is auftauchen a separable verb, and why is it written as one word here?

Yes, auftauchen is separable (auftauchen = tauchen ... auf in a main clause).
But in a subordinate clause the separable prefix stays attached, so you get auftaucht as one word:

• Main clause: Das Problem taucht wieder auf.
• Subordinate clause: ..., falls das Problem wieder auftaucht.

What does wieder mean here, and can it move around?

wieder means again. Its position is fairly flexible but affects emphasis slightly. Common options:

• falls das Problem wieder auftaucht (neutral: shows up again)
• falls das Problem auftaucht wieder (generally less natural)
• falls wieder das Problem auftaucht (emphasis on again, but stylistically marked)

Could the sentence start with the falls clause?

Yes. If the subordinate clause comes first, the main clause verb comes immediately after it (inversion):

• Falls das Problem wieder auftaucht, soll der Hausmeister morgen die Sicherung austauschen.
  Notice the comma after the subordinate clause and soll still near the start of the main clause.