Sobald der Heizkreis entlüftet ist, steigt die Rücklauftemperatur.

to be

Breakdown of Sobald der Heizkreis entlüftet ist, steigt die Rücklauftemperatur.

• sobald: as soon as
• steigen: to rise
• der Heizkreis: the heating circuit

Questions & Answers about Sobald der Heizkreis entlüftet ist, steigt die Rücklauftemperatur.

Why does ist come at the end of Sobald der Heizkreis entlüftet ist?

Because sobald introduces a subordinate clause. In German, the conjugated verb usually goes to the end of a subordinate clause.

So:

• Sobald = as soon as
• der Heizkreis = the heating circuit
• entlüftet ist = is vented / has been bled

This is the normal pattern:

• Sobald + subject + ... + verb

Compare:

• Der Heizkreis ist entlüftet. = The heating circuit is vented.
• Sobald der Heizkreis entlüftet ist, ... = As soon as the heating circuit is vented, ...

Why is it steigt die Rücklauftemperatur and not die Rücklauftemperatur steigt?

Because the sentence starts with a subordinate clause:

• Sobald der Heizkreis entlüftet ist, ...

When a subordinate clause comes first, it takes up position 1 in the main clause structure. In a German main clause, the finite verb must come in position 2. So the next thing after the comma is the verb:

• Sobald der Heizkreis entlüftet ist, steigt die Rücklauftemperatur.

This is the same rule you see in sentences like:

• Heute geht er nach Hause.
• Wenn ich Zeit habe, komme ich.

So steigt comes before die Rücklauftemperatur because German is following the verb-second rule.

What exactly does sobald mean, and how is it different from wenn?