diff --git a/site_ansto/instrument/config/environment/temperature/sct_oxford_mercury.tcl b/site_ansto/instrument/config/environment/temperature/sct_oxford_mercury.tcl
index a693a605..df8ee782 100644
--- a/site_ansto/instrument/config/environment/temperature/sct_oxford_mercury.tcl
+++ b/site_ansto/instrument/config/environment/temperature/sct_oxford_mercury.tcl
@@ -225,18 +225,17 @@ proc ::scobj::oxford_mercury::rdValue {tc_root} {
     }
 # rdValue hook code starts
     set value [lindex [split "${data}" ":"] end]
-    if {[string equal -nocase [string index ${value} end] K]} {
-      set value [string range ${value} 0 end-1]
-    }
-    if {[string equal -nocase ${value} NaN]} {
+    if {[string equal -nocase -length 3 ${value} NaN]} {
       set value 0
     }
-    if {[string equal -nocase ${value} inf] || [string equal -nocase ${value} -inf]} {
+    if {[string equal -nocase -length 3 ${value} inf] || [string equal -nocase -length 4 ${value} -inf]} {
       set value 0
     }
-    if {![string is double ${value}]} {
+    if {![string is digit [string index ${value} 0]]} {
       set value 0
     }
+    debug_log ${tc_root} 1 "rdValue tc_root=${tc_root} sct=[sct] result=[sct result]"
+    debug_log ${tc_root} 1 "rdValue tc_root=${tc_root} data=${data} value=${value}"
     scan ${value} "%g" data
 # rdValue hook code ends
     if { [hpropexists [sct] geterror] } {
@@ -507,7 +506,7 @@ proc ::scobj::oxford_mercury::mkDriver { sct_controller name device_class simula
 
       if {[string equal -nocase [string index ${cards} 3] V] && [string equal -nocase [string index ${assoc} 4] 4]} {
         hfactory ${scobj_hpath}/Pres5/valve plain user float
-        hsetprop ${scobj_hpath}/Pres5/valve read ${ns}::getValue ${scobj_hpath} rdValue {READ:DEV:DB4.G1:AUX:SIG:OPEN}
+        hsetprop ${scobj_hpath}/Pres5/valve read ${ns}::getValue ${scobj_hpath} rdValue {READ:DEV:DB4.G1:AUX:SIG:PERC}
         hsetprop ${scobj_hpath}/Pres5/valve rdValue ${ns}::rdValue ${scobj_hpath}
         hsetprop ${scobj_hpath}/Pres5/valve control true
         hsetprop ${scobj_hpath}/Pres5/valve data true
@@ -624,7 +623,7 @@ proc ::scobj::oxford_mercury::mkDriver { sct_controller name device_class simula
 
       if {[string equal -nocase [string index ${cards} 3] V] && [string equal -nocase [string index ${assoc} 7] 4]} {
         hfactory ${scobj_hpath}/Pres8/valve plain user float
-        hsetprop ${scobj_hpath}/Pres8/valve read ${ns}::getValue ${scobj_hpath} rdValue {READ:DEV:DB4.G1:AUX:SIG:OPEN}
+        hsetprop ${scobj_hpath}/Pres8/valve read ${ns}::getValue ${scobj_hpath} rdValue {READ:DEV:DB4.G1:AUX:SIG:PERC}
         hsetprop ${scobj_hpath}/Pres8/valve rdValue ${ns}::rdValue ${scobj_hpath}
         hsetprop ${scobj_hpath}/Pres8/valve control true
         hsetprop ${scobj_hpath}/Pres8/valve data true
@@ -1384,7 +1383,7 @@ proc ::scobj::oxford_mercury::mkDriver { sct_controller name device_class simula
       }
 
       hfactory ${scobj_hpath}/Valve/sensor plain user float
-      hsetprop ${scobj_hpath}/Valve/sensor read ${ns}::getValue ${scobj_hpath} rdValue {READ:DEV:DB4.G1:AUX:SIG:OPEN}
+      hsetprop ${scobj_hpath}/Valve/sensor read ${ns}::getValue ${scobj_hpath} rdValue {READ:DEV:DB4.G1:AUX:SIG:PERC}
       hsetprop ${scobj_hpath}/Valve/sensor rdValue ${ns}::rdValue ${scobj_hpath}
       hsetprop ${scobj_hpath}/Valve/sensor control true
       hsetprop ${scobj_hpath}/Valve/sensor data true