Empire Comfort Systems DVLXB55BP90N-1 Installer's Manual page 61

For the Pressure Switch:
Remove the two silicone tubes from the pressure switch
(making note of which tube goes on each spigot).
Disconnect the two wires from the pressure switch and remove
the two screws on either side of the pressure switch to remove
it from the bracket. Replace the pressure switch and reattach
the screws and silicone tubes. The black hose should be
connected to the low pressure port and the translucent to the
high pressure port.
For the Exhaust TCO:
Reach into the access hatch and locate the TCO. The TCO
has two wires connected to the main body of the fireplace.
Remove these and unscrew the TCO by hand. Remove the
TCO from the fireplace, replace it, and re-attach the wires.
MAINTENANCE AND SERVICE
Wiring
If any of the original wire supplied with this unit must be
replaced, order from an Empire dealer.
TCO
Pressure Switch
61