ROBERTS GORDON® ULTRAVAC™ CONTROLLER INSTALLATION MANUAL
SECTION 8: COMMISSIONING THE CORAYVAC® SYSTEM
NOTE: The ROBERTS GORDON® ULTRAVAC™ software must be installed on the PC, the communi- cation connection must be made to the controller and all wiring of the ROBERTS GORDON® ULTRAVAC™ control boards, relay boards, burners, pumps and VFD must be completed before starting the commis- sioning procedure.
8.1 Setting The CORAYVAC® End Burner Vacuum
It is important to understand that the frequency that the VFD runs the motor at, determines the speed of the impeller in the pump. Variation of the impeller speed will increase or decrease vacuum in the sys- tem. The following procedure will help you set mini- mum and maximum VFD frequency settings to achieve proper vacuum in the system.
Step 8.1.1 At the controller, turn on the 24 V power switch on the relay board. At the PC, "connect" to the controller (see the ROBERTS GORDON® ULTRAVAC™ Software Installation and Operation Manual, P/N 10081600NA for details) and then open the manual override screen(Alt + M). On the screen, click the "ON" button for the vacuum pump. Wait 30 seconds then click the ON button for zones 1- 3.
Step 8.1.2 The pump should be running and the
burners should light within 60 seconds. At the VFD, verify that the number displayed on the LCD screen is "60.0" If it is lower than 60.0, hit the "up" arrow but- ton on the VFD until the number reads 60.0 Let the burners fire for approximately
If the lowest end vent vacuum reading is above 3.0" wc, reduce the vacuum pump speed. Generally, the lowest end vent vacuum reading is on the longest branch of the system. Use the down arrow button on the VFD to reduce the frequency of the output signal to the pump, thus reducing the pump speed and low- ering the end vent vacuum reading. Continue to reduce the frequency until the end vent vacuum read- ing is between 2.5" - 3.0" wc. Make note of this fre- quency setting below. The frequency is found on the VFD’s LCD screen.
2.5" wc - 3.0" wc VFD Frequency Setting
Record Frequency Setting Here:
To avoid damage to the pump motor, do not adjust the frequency above 60.0 Hz. Verify that the end vent
vacuum readings in the remaining branches are proper. If necessary, adjust the proper damper cou- pling to achieve an end vent vacuum of 2.5" - 3.0" wc. See Page 45, Figure 26. Damper couplings should be found near the end of the radiant portion of the pipe in each branch or where a branch connects to other branches at a cross or tee. See Page 46, Fig- ure 27.
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