John Wood Atmospheric Gas (Standard) - Manual (Page 26)

26
Replacing the Pilot/ Thermopile Assembly
1. Remove the manifold door assembly as described in
“Removing the Manifold/Burner Assembly” section.
2. Remove the burner to access the pilot/thermopile
assembly. Remove and keep the screws securing the
burner to the manifold (Figure 23).
IMPORTANT: DO NOT remove the orifice.
3. Remove the screw securing the pilot/thermopile assembly
and pilot shield to the pilot bracket and keep for reuse later
(Figure 23).
4. Lift the retainer clip straight up from the back of
the manifold component block (using a flat-blade
screwdriver), then remove the manifold component
block from the manifold door (Figure 23). IMPORTANT:
Be careful not to bend or alter the position of the pilot
tube. It will be used as a bending template for the new
pilot assembly. Note the placement/order of the wires in
the manifold component block.
5. Lift the pilot/thermopile assembly (including the igniter
wire) from the manifold assembly.
CONNECTORS
MANIFOLD COMPONENT
BLOCK
PILOT TUBE
IGNITER
WIRE
BURNER AND OTHER
FITTINGS NOT SHOW
FOR CLARITY.
MANIFOLD DOOR
RED WIRES TO
THERMAL SWITCH (2)
RETAINER
CLIP
PILOT / THERMOPILE
ASSEMBLY SCREW
PILOT SHIELD
FIGURE 23.
6. Read this step carefully before proceeding. Using the
old pilot/pilot tube assembly as a guide, bend the new
pilot tube to match the old one. Make only the bends
closest to the pilot before going to the next step.
PILOT/THERMOPILE ASSEMBLY
PILOT/THERMOPILE
ASSEMBLY
IGNITER
CONNECTOR
THERMAL
SWITCH
CONNECTORS
(RED WIRES)
PILOT THERMOPILE
CONNECTORS
(CONNECT AT
GAS CONTROL VALVE/
THERMOSTAT)
FOR CLARITY, PILOT
TUBE NOT SHOWN .
FIGURE 24.
7. Route the new pilot tube, igniter wire and thermopile wire
through the opening in the manifold door. See Figure 23.
8. Using the pilot screw removed earlier, attach the new
pilot/thermopile assembly and the pilot shield. Reattach
the burner to the manifold using the screws removed
earlier. NOTE: Make sure the burner scoop is oriented to
the pilot side of the manifold tube (Figure 22).
9. Reinstall the manifold component block in the manifold
door. Ensure that the pilot tube and wires are positioned
as shown in Figure 25.
RED THERMAL SWITCH WIRES
CONNECTION AT MANIFOLD DOOR
RED (+) THERMAL SWITCH WIRE
CONNECTS TO THE GAS CONTROL
VALVE\THERMOSTAT.
WHITE (-) THERMOPILE WIRE
CONNECTS TO THE GAS CONTROL
VALVE\THERMOSTAT.
IGNITER WIRE PASSES
THROUGH CENTER OF
MANIFOLD COMPONENT
BLOCK (SMALLEST HOLE)
PILOT TUBE PASSES
THROUGH BOTTOM HOLE
OF MANIFOLD COMPONENT
BLOCK (LARGEST HOLE)
THERMOPILE WIRES PASS
THROUGH TOP HOLE OF
MANIFOLD COMPONENT
BLOCK
MANIFOLD
COMPONENT
BLOCK
FIGURE 25.
10. Carefully bend the new pilot tube to match the bend of
the manifold tube. NOTE: When bending, DO NOT crimp
or crease the pilot tube.
11. Before you proceed to the next step, install the new
brass ferrule nut in the gas control valve/thermostat’s
pilot tube opening, HAND TIGHT ONLY.
12. Install the manifold/burner assembly. Refer to the
“Replacing the Manifold/Burner Assembly” section for
instructions.