diff --git a/fhem/FHEM/94_PWM.pm b/fhem/FHEM/94_PWM.pm
index ec953beb5..15f81331b 100644
--- a/fhem/FHEM/94_PWM.pm
+++ b/fhem/FHEM/94_PWM.pm
@@ -34,6 +34,7 @@
 # 05.02.18 GA fix typo overallHeatingSwitchThresholdTemup
 # 19.11.18 GA add support for attribute maxOffTime
 # 05.03.19 GA fix reading maxOffTimeCalculation was set but not used
+# 30.12.19 GA fix access to ReadingsVal via $name (reported by stromer-12)
 
 ##############################################
 # $Id$
@@ -901,7 +902,7 @@ PWM_CalcRoom(@)
       # ----------------
       # check if maxOffTime protection is activated (attribute maxOffTimeIdlePeriod is set)
 
-      if ($maxOffTimeApply > 0 and ReadingsVal($hash, "maxOffTimeCalculation", "off") eq "on") {
+      if ($maxOffTimeApply > 0 and ReadingsVal($name, "maxOffTimeCalculation", "off") eq "on") {
 
         ## wz > 2:00
         if ($maxOffTimeAct >= $maxOffTime) {