diff --git a/erpnext/accounts/doctype/payment_entry/payment_entry.py b/erpnext/accounts/doctype/payment_entry/payment_entry.py
index b7ab4fe..9033f65 100644
--- a/erpnext/accounts/doctype/payment_entry/payment_entry.py
+++ b/erpnext/accounts/doctype/payment_entry/payment_entry.py
@@ -161,7 +161,7 @@
 					d.reference_name, self.party_account_currency)
 
 				for field, value in iteritems(ref_details):
-					if not d.get(field) or force:
+					if field == 'exchange_rate' or not d.get(field) or force:
 						d.set(field, value)
 
 	def validate_payment_type(self):