diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index d8424f62..146b9656 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -326,7 +326,7 @@ def nicepaceformat(values):
 
 # Convert seconds to a Time Delta value, replacing NaN with a 5:50 pace
 def timedeltaconv(x):
-    if not np.isnan(x):
+    if not np.isnan(x) and x != 0:
         dt = datetime.timedelta(seconds=x)
     else:
         dt = datetime.timedelta(seconds=350.)