Operating instructions

53
Start-Up Procedures
Fluctuating Water Temperature
Domestic water temperatures can fluctuate
with factory control settings when the domestic
hot water flow is less than 0.7 gpm. The fluc-
tuation is due to the interaction between the
domestic water flow switch minimum setting
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
below the domestic flow switch minimum set-
ting. The appliance cycles off until the mixing
valve opens calling for more domestic water.
To improve the domestic hot water perfor-
mance at low flows it is recommended to
reduce the domestic hot water temperature set-
point on the control down from 140°F (60°C)
to 125°F (52°C), see page 52 and or to turn the
domestic function on the control to ON or
ECO, see page 49. Additionally, ensure the
minimum domestic water pressure is 40 psi
(2.8 bar), see page 21. A lower domestic hot
water temperature setpoint will reduce the
domestic hot water temperature at higher
domestic flows.
Error (Hard Lockout) Mode
If a system fault occurs, the system enters a
hard lockout condition which requires a manu-
al 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
light above the reset button. The error code
is located on the main display. The error must
be corrected before the control will reset.
The appliance freeze protection feature
is disabled during a Hard Lockout, how-
ever the CH circulator will operate.
During a hard lockout or low water con-
dition the appliance will not re-start
without service. If the heating system is
left unattended in cold weather appro-
priate safeguards or alarms should be
installed to prevent property damage.
CAUTION
CAUTION
Table 6: 12 K Ohm NTC Sensor Resistance