diff --git a/succbone/succd/modbus.go b/succbone/succd/modbus.go
index 61f38de..ed33f7e 100644
--- a/succbone/succd/modbus.go
+++ b/succbone/succd/modbus.go
@@ -107,18 +107,18 @@ func (d *daemon) modbusUpdate() error {
 	// KFA1-KFA8
 	var relayState [8]bool
 
-	// -KFA1 Roughing Pump
-	relayState[0] = d.daemonState.rpOn
+	// -KFA1 Roughing Pump (normally closed contact)
+	relayState[0] = !d.daemonState.rpOn
 	// -KFA2 Diffusion Pump
 	relayState[1] = d.daemonState.dpOn
 	// -KFA4 Button Vent
 	relayState[3] = d.daemonState.vent.output
 	// -KFA5 Button Pump-Down
 	relayState[4] = d.daemonState.pumpdown.output
-	// -KFA6 Fake-Pirani Rough
-	relayState[5] = d.aboveRough.output
-	// -KFA7 Fake-Pirani High
-	relayState[6] = d.aboveHigh.output
+	// -KFA6 Fake-Pirani Rough (normally closed contact)
+	relayState[5] = !d.aboveRough.output
+	// -KFA7 Fake-Pirani High (normally closed contact)
+	relayState[6] = !d.aboveHigh.output
 
 	// The KEC1 module uses a non-standard MODBUS interface
 	// instead of coils