diff --git a/src/pandapipes/test/pipeflow_internals/test_time_series.py b/src/pandapipes/test/pipeflow_internals/test_time_series.py
index 7720c38a..0d3d25fa 100644
--- a/src/pandapipes/test/pipeflow_internals/test_time_series.py
+++ b/src/pandapipes/test/pipeflow_internals/test_time_series.py
@@ -79,6 +79,7 @@ def _data_source():
 
 
 def _compare_results(ow):
+    _compare_results_default_ow(ow)
     test_res_ext_grid = pd.read_csv(os.path.join(data_path, 'test_time_series_results', 'res_ext_grid',
         'mdot_kg_per_s.csv'), sep=';', index_col=0)
     res_ext_grid = ow.np_results["res_ext_grid.mdot_kg_per_s"]
@@ -87,6 +88,25 @@ def _compare_results(ow):
     diff = 1 - res_ext_grid.round(9) / test_res_ext_grid.round(9)
     check = diff < 0.0001
     assert (np.all(check))
+    test_res_sink = pd.read_csv(os.path.join(data_path, 'test_time_series_results', 'res_sink',
+        'mdot_kg_per_s.csv'), sep=';', index_col=0)
+    res_sink = ow.np_results["res_sink.mdot_kg_per_s"]
+    res_sink = res_sink[~np.isclose(res_sink, 0)]
+    test_res_sink = test_res_sink.values[~np.isclose(test_res_sink.values, 0)]
+    diff = 1 - res_sink.round(9) / test_res_sink.round(9)
+    check = diff < 0.0001
+    assert (np.all(check))
+    test_res_source = pd.read_csv(os.path.join(data_path, 'test_time_series_results', 'res_source',
+        'mdot_kg_per_s.csv'), sep=';', index_col=0)
+    res_source = ow.np_results["res_source.mdot_kg_per_s"]
+    res_source = res_source[~np.isclose(res_source, 0)]
+    test_res_source = test_res_source.values[~np.isclose(test_res_source.values, 0)]
+    diff = 1 - res_source.round(9) / test_res_source.round(9)
+    check = diff < 0.0001
+    assert (np.all(check))
+
+
+def _compare_results_default_ow(ow):
     test_res_junction = pd.read_csv(os.path.join(data_path, 'test_time_series_results', 'res_junction',
         'p_bar.csv'), sep=';', index_col=0)
     res_junction = ow.np_results["res_junction.p_bar"]
@@ -103,22 +123,6 @@ def _compare_results(ow):
     diff = 1 - res_pipe.round(9) / test_res_pipe.round(9)
     check = diff < 0.0001
     assert (np.all(check))
-    test_res_sink = pd.read_csv(os.path.join(data_path, 'test_time_series_results', 'res_sink',
-        'mdot_kg_per_s.csv'), sep=';', index_col=0)
-    res_sink = ow.np_results["res_sink.mdot_kg_per_s"]
-    res_sink = res_sink[~np.isclose(res_sink, 0)]
-    test_res_sink = test_res_sink.values[~np.isclose(test_res_sink.values, 0)]
-    diff = 1 - res_sink.round(9) / test_res_sink.round(9)
-    check = diff < 0.0001
-    assert (np.all(check))
-    test_res_source = pd.read_csv(os.path.join(data_path, 'test_time_series_results',
-        'res_source', 'mdot_kg_per_s.csv'), sep=';', index_col=0)
-    res_source = ow.np_results["res_source.mdot_kg_per_s"]
-    res_source = res_source[~np.isclose(res_source, 0)]
-    test_res_source = test_res_source.values[~np.isclose(test_res_source.values, 0)]
-    diff = 1 - res_source.round(9) / test_res_source.round(9)
-    check = diff < 0.0001
-    assert (np.all(check))
 
 
 def _output_writer(net, time_steps, ow_path=None):
@@ -173,7 +177,7 @@ def test_time_series_default_ow():
     max_iter_hyd = 8
     run_timeseries(net, time_steps, max_iter_hyd=max_iter_hyd, calc_compression_power = False)
     ow = net.output_writer.iat[0, 0]
-    _compare_results(ow)
+    _compare_results_default_ow(ow)
 
 
 if __name__ == "__main__":
diff --git a/src/pandapipes/timeseries/run_time_series.py b/src/pandapipes/timeseries/run_time_series.py
index 34c74167..99b04a34 100644
--- a/src/pandapipes/timeseries/run_time_series.py
+++ b/src/pandapipes/timeseries/run_time_series.py
@@ -39,9 +39,6 @@ def init_default_outputwriter(net, time_steps, **kwargs):
         net.output_writer.iat[0, 0] = output_writer
     if "output_writer" not in net or net.output_writer.iat[0, 0] is None:
         ow = OutputWriter(net, time_steps, output_path=tempfile.gettempdir(), log_variables=[])
-        ow.log_variable('res_sink', 'mdot_kg_per_s')
-        ow.log_variable('res_source', 'mdot_kg_per_s')
-        ow.log_variable('res_ext_grid', 'mdot_kg_per_s')
         ow.log_variable('res_pipe', 'v_mean_m_per_s')
         ow.log_variable('res_junction', 'p_bar')
         ow.log_variable('res_junction', 't_k')