Service manual

VANTAGE
®
EV INSTALLATION MANUAL ROBERTS-GORDONpg 36
0
1
2
1
2
0.5" to 0.6"
Remove Cap
Attach Manometer Hose
Remove Cap
Attach Manometer Hose
Manometer
Burner
Figure 33. Vacuum Differential Reading
Setting the Vacuum
1. Set thermostats above room temperature. See that all
burners are operating properly.
2. Allow at least one-half hour operation for temperature
to normalize before checking system vacuum balance.
Vacuum differential can be measured by connecting a
manometer across the “tee” tappings inside the control
housing (after measurement, the caps must be
installed on the “tees” to prevent leakage). See Figure
33 for manometer connection to burner control
housing.
Approximately 1.0” w.c. of vacuum differential is
required at the burner, when the system is cold.
Normal operating vacuum differential is 0.5" to 0.6"
w.c. Vacuum adjustments are made by means of the
damper inlet, and the adjustable damper coupling(s).
Check the vacuum differential at all burners, then
adjust the damper coupling to obtain approximately
equal vacuum differential readings. Then adjust the
pump inlet damper until vacuum differential readings
are a minimum 0.5" to 0.6" w.c.. With systems
designed to capacity, it may not be possible to obtain
vacuum differential readings at slightly above 1" w.c.
(when cold). If so, adjust damper couplings to
maximum but approximately equal vacuum readings.
Be sure to lock all dampers securely after adjustment.
3. Reset thermostats to desired room temperature.
4. If heat is not required, turn off main switch and close
main gas valve.