|
| LEGEND |
GV | Ð Gas Valve (Zone Module) | |
MB | Ð Main Burner | |
MGV | Ð | Main Manual Gas Valve |
PB | Ð | Pilot Burner |
NOTE: Unit is equipped with a
vices:
Fig. 32 Ð Gas Piping Schematic
3.Turn system switch to ON position. Set each zone ther- mostat at setting to call for heat. Pilot will ignite.
NOTE: A
4.Remove burner access panel.
5.Remove
6.Turn system switch to OFF position.
7.Reconnect main gas valve wires to W1 on pilot switches.
8.Set system switch at ON position, and set zone thermo- stats as desired.
9.Replace burner access panel.
PRESSURE ADJUSTMENT (NATURAL GAS)
1.Turn control circuit service switch to OFF position, and set thermostat at lowest setting.
2.Remove the 2 heating control access panels and the burner access panel.
3.Remove plug from zone manifold pressure tap. Connect suitable gage. Route gage line through pilot switch grom- met so that burner access panel may be closed.
4.Close burner access panel.
5.Turn control circuit service switch to ON position. Set zone thermostat to call for heat. After pilot is proven, burner will operate.
NOTE: A
6.Remove screw cap from zone module gas valve pres- sure regulator to expose pressure adjustment screw.
7.Turn pressure adjustment screw with a small screw- driver until 3.5 in. wg is achieved.
8.Replace screw cap.
9.Turn control circuit service switch to OFF position and set zone thermostat at lowest position.
10.Remove burner access panel. Disconnect gage line con- nection on zone manifold. Replace plug in manifold pres- sure tap.
11.Repeat steps
12.Replace all unit panels. Turn control circuit service switch to ON position, and set zone thermostat as desired.
Main Burner Adjustment (48MA) Ð Flame should appear clear blue (almost transparent) in color with a well- de®ned inner cone. If there is insufficient primary air, ¯ame will be yellow tipped. If there is too much primary air, ¯ame will be well de®ned but have a tendency to lift or dance off ports. Allow unit to operate for at least 15 minutes before making ®nal primary air adjustment.
ORIFICE ALIGNMENT Ð The most likely cause of burner ¯ame ¯ashback is misalignment of the burner ori®ce. Be sure that ori®ce points straight down the burner.
PRIMARY AIR ADJUSTMENT Ð Observe ¯ame charac- teristics through view ports in main burner access panel. Turn off main manual gas valves in burner control compartment. Then remove main burner access panel.
If Flame Is Yellow (Insufficient Primary Air) Ð Turn spoiler screw counterclockwise about 4 turns for each 1¤4 in. of change in spoiler length. See Fig. 33 for spoiler screw location.
If Flame Lifted Off Ports (Too Much Primary Air) Ð Turn spoiler screw clockwise about 4 turns for each 1¤4 in. of change in spoiler length. See Fig. 33 for spoiler screw location.
Replace main burner access panel and turn on main manual gas valves. Observe ¯ame characteristics. Repeat these pro- cedures as required until correct ¯ame characteristics are achieved.
36