Xylem MM 802F Model TC-4 Test-N-Check Valves For Hot Water Boilers - Manual (Page 4)

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1. Assemble the TC-U (the upper Test-N-Check
valve, with the vacuum breaker) into the upper
equalizing line in place of the cross described
in the low water cut-off installation instructions.
NOTE: The vacuum breaker must be on the top
and the long leg must face the boiler. NOTE:
Make sure low water cut-off position is located
in accordance with the boiler manufacturer’s
recommended cut-off level.
2. Assemble the TC-L (the lower Test-N-Check
valve, without the vacuum breaker) into the
lower equalizing line in place of the cross
described in the low water cut-off installation
instructions. NOTE: The brass cap must be
located above the center of the lower equalizing
line, and the long leg must face the boiler.
3. Assemble the blow-down valve into the bottom
port of the TC-L.
4. Assemble 1” NPT pipe plugs into the remaining
open port in both the TC-U and TC-L.
5. Complete the installation as described in the
low water cut-off installation instructions.
6. After all piping assembly has been completed,
refill the system with water, turn on all electrical
supply and bring system to operating condi-
tions. After system reaches operating pressure,
inspect to make sure no leaks exist at the
threaded connections. Test valves by opening
blow-down valve while burner is on, to make
sure valves operate correctly and low water cut-
off shuts burner off.
Simplify Testing of Low Water Cut-offs on Hot Water Boilers
TEST-N-CHECK ® VALVES
Installation of the TC-4 Test-N-Check Valves with a New Low Water Cut-off
TC-U in Place
Blow-down Valve
TC-L
in Place
LWCO
Brass
Cap
To prevent serious personal injury from steam pipe blow down, connect a
drain pipe to the control opening to avoid exposure to steam discharge.
If vacuum breaker stem is accidentally depressed, hot water could be dis-
charged causing burns.
Failure to follow this caution could cause personal injury.
! CAUTION
IMPORTANT:
• When using tape sealant or thread joint compound on pipe or fittings with external threads follow
manufacturer’s instructions. Do not use tape sealant or thread joint compound on first thread.
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