Over Temperature Limit Switch; Adjustments - Aerco KC Series Installation, Operation & Maintenance Instructions Manual

4.6.3 MAXIMUM LOAD ADJUSTMENT
1. Enter the SECONDARY menu of the
temperature controller by simultaneously
!
pressing and ENTER.
2. Press INDEX until Pct is displayed. This is
the unit's percentage of firing rate.
3. Create a maximum load on the system that
will yield a steady percentage of firing rate
between 80% to 90%.
NOTE:
It may be necessary to open the outlet valve
if it was closed during minimum load
adjustment to obtain a sufficient flow rate for
maximum adjustment.
4. Press the INDEX button until tout appears in
the lower display. The upper display will be
indicating the outlet water temperature.
5. Wait a few minutes to allow the outlet
temperature to stabilize.
6. Once stabilized the outlet temperature should
be 2 to 3 degrees below the set point
temperature. If it does not stabilize to 2 to 3
degrees then the Sensitivity (SEnS) must be
adjusted.
7. To adjust the SEnS press INDEX until SEnS
appears in the lower display (see figure 4.7).
8. Raise or lower this value as needed using the
!,"
arrow keys. Increasing this value will
increase water temperature, decreasing it will
decrease water temp
9. Press ENTER to accept the new value. Allow
time for the system to settle between

adjustments.

Figure 4.7
Secondary Menu Displaying Sensitivity
10. If the outlet temperature holds setpoint
temperature stable, and within the +/_ 4
no further control adjustment is required.
11. If the outlet temperature does not maintain
setpoint after a reasonable amount of time
and adjustment contact your local AERCO
representative.
Figure 4.8
Over Temperature Limit Switch Location

4.7 OVER TEMPERATURE LIMIT SWITCH

ADJUSTMENTS
There are two over-temperature limit switches
that will turn off the unit when the outlet water
temperature becomes too hot. The lower over-
temperature limit switch is adjustable and should
o
be adjusted to 20 F above the highest operating
temperature the system will see. The upper over-
temperature limit switch is a locked manual non-
adjustable reset device. It will trip the unit off at
23
INITIAL START-UP
0
F,