diff --git a/appveyor.yml b/appveyor.yml
index 0e99f1f..382d261 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -32,7 +32,7 @@ init:
   - set EPANET_HOME=%APPVEYOR_BUILD_FOLDER%
   - set BUILD_HOME=buildprod
   - set TEST_HOME=nrtestsuite
-  - set NRTEST_SCRIPT=C:\Python27\Scripts
+
   # See values set
   - echo %APPVEYOR_BUILD_WORKER_IMAGE%
   - echo %BUILD_HOME%
@@ -67,7 +67,7 @@ test_script:
   - ctest -C Release
   # run regression tests
   - cd %EPANET_HOME%
-  - tools\run-nrtest.cmd %NRTEST_SCRIPT% %TEST_HOME% %APPVEYOR_REPO_COMMIT%
+  - tools\run-nrtest.cmd %APPVEYOR_REPO_COMMIT%
 
 after_test:
   # zip up the SUT benchmarks
diff --git a/tools/run-nrtest.cmd b/tools/run-nrtest.cmd
index db4174f..d20087b 100644
--- a/tools/run-nrtest.cmd
+++ b/tools/run-nrtest.cmd
@@ -7,24 +7,35 @@
 ::          US EPA - ORD/NRMRL
 ::
 ::  Arguments:
-::    1 - nrtest script path
-::    2 - test suite path
-::    3 - version/build identifier
+::    1 - version/build identifier
+::    2 - (test suite path)
 ::
 
 @echo off
 setlocal
 
-set NRTEST_SCRIPT_PATH=%~1
-set TEST_SUITE_PATH=%~2
 
 set BENCHMARK_VER=220dev5
 
 
+:: Determine location of python Scripts folder
+FOR /F "tokens=*" %%G IN ('where python') DO (
+  set PYTHON_DIR=%%~dpG
+)
+set "NRTEST_SCRIPT_PATH=%PYTHON_DIR%Scripts"
+
+:: Check existence and apply default arguments
+IF NOT [%1]==[] ( set "SUT_VER=%~1"
+) ELSE ( set "SUT_VER=vXXX" )
+
+IF NOT [%2]==[] ( set "TEST_SUITE_PATH=%~2"
+) ELSE ( set "TEST_SUITE_PATH=nrtestsuite" )
+
+
 set NRTEST_EXECUTE_CMD=python %NRTEST_SCRIPT_PATH%\nrtest execute
-set TEST_APP_PATH=apps\epanet-%3.json
+set TEST_APP_PATH=apps\epanet-%SUT_VER%.json
 set TESTS=tests\examples tests\exeter tests\large tests\network_one tests\press_depend tests\small tests\tanks tests\valves
-set TEST_OUTPUT_PATH=benchmark\epanet-%3
+set TEST_OUTPUT_PATH=benchmark\epanet-%SUT_VER%
 
 set NRTEST_COMPARE_CMD=python %NRTEST_SCRIPT_PATH%\nrtest compare
 set REF_OUTPUT_PATH=benchmark\epanet-%BENCHMARK_VER%