User Guide

12
6. Appliance Control Display
6.5 Error Mode
If a boiler fault occurs, the CHALLENGER enters a hard lockout
c
ondition which requires a manual reset by pressing the reset
button
. A hard lock is indicated by a flashing [E] on the operating
display as well as a flashing LED above the reset button. The error
c
ode is shown on the main display. The error must be corrected
before the control will reset.
6.6 Fluctuating DHW Temperature
Domestic water temperatures can fluctuate when the domestic hot
water flow is less than 0.7 gpm. The fluctuation is due to the
interaction between the minimum domestic hot water flow rate of 0.5
gpm and the domestic hot water mixing valve. As the domestic hot
water leaving the appliance approaches the domestic hot water
mixing valve setting, the mixing valve reduces the amount of hot
water through the appliance. The appliance cycles off when water flow
through the appliance dips below 0.5 gpm. To improve the domestic
hot water performance at low flows it is recommended to reduce the
domestic hot water temperature setpoint on the control down from
140°F (60°C) to 125°F (52°C), see Section 12.8 in the CHALLENGER
Combit Installation Manual, or to turn domestic function on the
control to ON or ECO, see Section 6.3.
The appliance freeze protection feature is disabled dur-
ing a Hard Lockout, however the CH circulator will oper-
ate.
CAUTION
During a hard lockout or low water condition the appli-
ance will not re-start without service. If the heating
system is left unattended in cold weather appropriate
safeguards or alarms should be installed to prevent
property damage.
CAUTION
Table 1: 12 kOhm NTC Sensor Resistance
Temperature (°F) Temperature (°C) NTC (kOhm)
-22 -30 171.70
-
4 -20 98.82
14 -10 58.82
32 0 36.10
50 10 22.79
68 20 14.77
78 25 12.00
86 30 9.81
104 40 6.65
122 50 4.61
140 60 3.25
158 70 2.34
176 80 1.71
194 90 1.27
212 100 0.95