Tjernlund WHKE Millivolt Interlock Kit (Compatible with UC1 Control) 8504108 Rev 08/02 - Manual (Page 2)

GAS PRESSURE SWITCH INSTALLATION
The gas pressure switch is mounted on the casing of the water heater adjacent to the heater's thermostat/gas control valve. It should be
mounted close enough so that the supplied 1/4" tubing will reach from the gas pressure switch fitting to the thermostat/gas valve pres-
sure tap port. The two provided screws are self-tapping and drilling. The screws do not require the use of a drill and their 1/2" length
assures that the inner tank will not be penetrated.
1. Mount the gas pressure switch by securing it to the heater casing with a screw in each of the two mounting holes.
IMPORTANT: Mount gas pressure switch so that diaphragm is in a VERTICAL position, (See Diagram C).
2. Install the supplied 1/8"-NPT pipe plug to the 90 o port of the supplied 1/8-NPT black pipe tee, (See Diagram C).
Use thread sealant, do not over tighten.
3. Install the 1/8-NPT black pipe tee to the gas pressure switch, (See Diagram C). Use thread sealant, do not over
tighten. CAUTION: Utilize the hex nut on the gas pressure switch when attaching the black pipe tee.
4. Install the supplied Brass 1/8-NPT male x ¼" compression fitting to the 1/8-NPT black pipe tee, (See Diagram C).
Use thread sealant, do not over tighten.
5. Remove the PRESSURE TAP plug from the underside of the thermostat/gas control valve and install the supplied Brass
1/8-NPT male x ¼" compression fitting, (See Diagram C). Use thread sealant, do not over tighten.
IMPORTANT: DO NOT alter the heater's PILOT GAS LINE, (See Diagram C).
6. Using a tube cutter, cut the appropriate length of the supplied 1/4" tubing to reach from the gas pressure switch fitting to the
PRESSURE TAP PORT fitting of the thermostat/gas control valve. Make sure each end of the tubing is not pinched closed.
7. Use the 1/4" tubing to connect gas pressure switch fitting to the PRESSURE TAP PORT fitting on the thermostat/gas control valve.
8. Conduct a gas leakage test of all connections as outlined in the latest edition of NFPA 54, ANSI Z223.1, part 4. or local codes.
NOTE: A "gauge port" can be accessed by removing the 1/8-NPT pipe plug that is on the 1/8-NPT black pipe tee (attached to
the gas pressure switch).
DO NOT ALTER
GAS SUPPLY
INTO PRESSURE TAP PORT.
GAS PRESSURE SWITCH
GAS CONTROL VALVE
THERMOSTAT/
PILOT GAS LINE
FIGURE 700S107 2/13/04
INSTALL BRASS 1/8-NPT MALE
x 1/4" COMPRESSION FITTING
THERMOCOUPLE
BURNER GAS LINE
COMMON
MUST BE MOUNTED VERTICALLY.
GAS PRESSURE SWITCH DIAPHRAGM
IMPORTANT:
BRASS 1/8-NPT MALE x 1/4"
COMPRESSION FITTING
THERMOSTAT / GAS CONTROL
TO PRESSURE TAP FITTING OF
1/4" OUTSIDE DIAMETER
ALUMINUM TUBING - CONNECT
VALVE.
1/8-NPT BLACK PIPE TEE
1/8-NPT PIPE PLUG - NEW
PRESSURE TAP PORT NORMALLY OPEN
MOUNTING HOLES
IMPORTANT:
DIAGRAM C