diff --git a/api/s5_pipes.py b/api/s5_pipes.py
index 63f36f8..b7b20c6 100644
--- a/api/s5_pipes.py
+++ b/api/s5_pipes.py
@@ -94,6 +94,8 @@ def _set_pipe(name: str, id: str, key: str, key_type: str, value: str, optional:
 def set_pipe_node1(name: str, id: str, node1: str) -> ChangeSet:
     if not is_node(name, node1):
         return ChangeSet()
+    if get_pipe_node2(name, id) == node1:
+        return ChangeSet()
 
     return _set_pipe(name, id, 'node1', 'str', str(node1))
 
@@ -101,6 +103,8 @@ def set_pipe_node1(name: str, id: str, node1: str) -> ChangeSet:
 def set_pipe_node2(name: str, id: str, node2: str) -> ChangeSet:
     if not is_node(name, node2):
         return ChangeSet()
+    if get_pipe_node1(name, id) == node2:
+        return ChangeSet()
 
     return _set_pipe(name, id, 'node2', 'str', str(node2))
 
diff --git a/api/s6_pumps.py b/api/s6_pumps.py
index 679bdac..39eeb9e 100644
--- a/api/s6_pumps.py
+++ b/api/s6_pumps.py
@@ -67,6 +67,8 @@ def _set_pump(name: str, id: str, key: str, key_type: str, value: str, optional:
 def set_pump_node1(name: str, id: str, node1: str) -> ChangeSet:
     if not is_node(name, node1):
         return ChangeSet()
+    if get_pump_node2(name, id) == node1:
+        return ChangeSet()
 
     return _set_pump(name, id, 'node1', 'str', str(node1))
 
@@ -74,6 +76,8 @@ def set_pump_node1(name: str, id: str, node1: str) -> ChangeSet:
 def set_pump_node2(name: str, id: str, node2: str) -> ChangeSet:
     if not is_node(name, node2):
         return ChangeSet()
+    if get_pump_node1(name, id) == node2:
+        return ChangeSet()
 
     return _set_pump(name, id, 'node2', 'str', str(node2))
 
diff --git a/api/s7_valves.py b/api/s7_valves.py
index adea81a..f1f9a7c 100644
--- a/api/s7_valves.py
+++ b/api/s7_valves.py
@@ -89,6 +89,8 @@ def _set_valve(name: str, id: str, key: str, key_type: str, value: str, optional
 def set_valve_node1(name: str, id: str, node1: str) -> ChangeSet:
     if not is_node(name, node1):
         return ChangeSet()
+    if get_valve_node2(name, id) == node1:
+        return ChangeSet()
 
     return _set_valve(name, id, 'node1', 'str', str(node1))
 
@@ -96,6 +98,8 @@ def set_valve_node1(name: str, id: str, node1: str) -> ChangeSet:
 def set_valve_node2(name: str, id: str, node2: str) -> ChangeSet:
     if not is_node(name, node2):
         return ChangeSet()
+    if get_valve_node1(name, id) == node2:
+        return ChangeSet()
 
     return _set_valve(name, id, 'node2', 'str', str(node2))