diff -r b73490398368 -r 8c7d87a2c094 thermferm/server.c
--- a/thermferm/server.c	Sun Aug 03 22:49:33 2014 +0200
+++ b/thermferm/server.c	Mon Aug 04 15:18:29 2014 +0200
@@ -1067,6 +1067,7 @@
 	unit->idle_rangeH = 1.0;
 	unit->idle_rangeL = -1.0;
 	unit->prof_started = (time_t)0;
+	unit->PID_err_old = 0.0;
 
 	if (Config.units == NULL) {
 	    Config.units = unit;