AERCO KC1000 Heater 2002 - Manual (Page 59)

MAINTENANCE
6-17
6.12 HYDRAULIC ZERO NEEDLE VALVE ADJUSTMENT (C-MORE CONTROL BOX)
The
Hydraulic Zero Needle Valve is factory set in new equipment and should not be changed unless the
BTU Transmitter is being replaced. If adjustment is necessary, the following procedure must be followed
to assure optimum temperature control.
Hydraulic Zero Needle Valve Adjustment Instructions
1) Enter
SETUP menu and change the password from 0 to 159, then press the ENTER key to activate
Level 1 access.
2) Scroll through the
TUNING menu until Outlet Feedback/YES is displayed. Press the CHANGE key,
then using the
UP or DOWN arrow keys, toggle the Outlet Feedback to NO and press ENTER to
accept the change.
3) Using a 7/16” wrench, loosen the locking nut on the hydraulic zero needle valve.
4) Rotate the needle valve fully clockwise, opening the valve.
5) Start the 3 to 6 GPM flow rate through the unit.
6) Place the temperature controller in
MANUAL mode and set a 20% firing rate.
7) Maintain an outlet temperature between 135
° and 140° F. Adjust firing rate as necessary to maintain
the above outlet temperature.
8) Scroll through the
TUNING menu to get FFW Temp (Feed Forward Temperature) displayed on the
top line. The temperature value is displayed on the bottom line. This is a measurement of the water
temperature at the BTU transmitter sensor.
9) Adjust the needle valve until the
FFW Temp is 18° to 24° F below the outlet temperature and stable
(i.e., if the outlet temperature is 135
° F, then the FFW Temp should read between 117° to 111° F.
Now complete the
Temperature Control Calibration per Section 4.6 in this manual. At the end of that
procedure, the
Feedback will be turned on prior to heater operation in automatic control.
NOTES:
1) The
BTU Transmitter assembly must be thoroughly cleaned prior to adjusting the Hydraulic Zero
Needle Valve.
2) The lock nut on the needle valve must be loosened prior to adjustment. The needle valve must be
open approximately 2-1/2 CCW turns prior to starting this procedure.
3) It is recommended that the unit’s outlet be closed off and the hose bib be used to set the 3 to 6 GPM
flow rate.
4) It is mandatory that the 3 to 6 GPM be steady. VARYING flow rates will result in improper setting of
the
Hydraulic Zero Needle Valve and temperature control inconsistencies.
NOTE
Close the needle valve CW to lower the
Feed Forward Temperature and open the needle valve CCW to
raise the
Feed Forward Temperature.
Once the hydraulic zero needle valve has been set, gently lock it in place using the locking nut.