SBD TANK TYPE HEATERS
SERVICE HANDBOOK
SBD GAS VALVE
The gas valves used on all SBD water heaters are 24 volt AC combination step opening gas valves. They incorporate the pilot valve, main valve, and gas pressure regulators into one body. The inlet view of the valve features a filter screen and the top knob. The top knob is a manual on/off gas control for both the pilot and main gas valves. When the top knob is placed on the black mark, gas is supplied only to the pilot valve.
On the top view, we see the pilot solenoid and pilot and main gas regulators. The top view also displays the “TH and “TR” terminals. The pilot gas regulator is found under its cover screw. It is factory preset at 3.5” W.C. but can be adjusted from
2.5to 5 inches water column. The main gas regulator is found under its cover screw. It is factory preset to 3.5 inches W.C. and adjusts gas pressure output from 2.5 to 5 inches water column. The two electrical terminals are marked TH and TR. The TH terminal is the common between the pilot valve solenoid coil and the main valve solenoid coil. The other wire emerging from the pilot solenoid connects to the pilot valve electrical output on the IID (terminal PV). The TR terminal connects directly to the main valve electrical output from the IID module
(terminal MV).
On the outlet view of the gas valve, we see the pilot gas connection port, manifold gas connection port, a limited bleed vent port, the manifold gas and pressure tap.
See step 18 for SBD-500 gas valve illustration
Technical Training Department | 11 |
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