Maintenance – AERCO KC1000 Water Heater July 2011 User Manual

Page 61

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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.

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.

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.

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.

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.

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