Troubleshooting
3A1570A 19
Heater
PROBLEM CAUSE SOLUTION
Primary heater(s) does not heat.
Heat turned off.
Press or zone
keys.
Temperature control alarm. Check temperature display for diag-
nostic code, page 9.
Signal failure from thermocouple. See E04: Fluid Temperature Sen-
sor (FTS) or thermocouple discon-
nected, page 11.
Control of primary heat is abnormal;
high temperature overshoots or E01
error occurs intermittently.
Dirty thermocouple connections. Examine connection of thermocou-
ples to long green plug on heater
control board. Unplug and re-plug
thermocouple wires, cleaning off any
debris. Unplug and re-plug long
green connector.
Thermocouple not contacting heater
element.
Loosen ferrule nut (N), push in ther-
mocouple (361) so tip (T) contacts
heater element (358). Holding ther-
mocouple tip (T) against heater ele-
ment, tighten ferrule nut (N) 1/4 turn
past tight. See page 30 for illustra-
tion.
Failed heater element. See Primary Heater, page 28.
Signal failure from thermocouple. See E04: Fluid Temperature Sen-
sor (FTS) or thermocouple discon-
nected, page 11.
Thermocouple wired incorrectly. See E04: Fluid Temperature Sen-
sor (FTS) or thermocouple discon-
nected, page 11. Power up zones
one at a time and verify that tempera-
ture for each zone rises.
A
B
