Xylem MM 802F Model TC-4 Test-N-Check Valves For Hot Water Boilers - Manual (Page 3)

1. Remove the existing low water cut-off by dis-
connecting the unions in the equalizing lines.
2. Remove the crosses from the upper and lower
equalizing lines.
3. Assemble the TC-U (the upper Test-N-Check
valve, with the vacuum breaker) into the upper
equalizing line replacing the cross. NOTE: The
vacuum breaker must be on the top and the
long leg must face the boiler.
4. Assemble the TC-L (the lower Test-N-Check
valve, without the vacuum breaker) into the
lower equalizing line replacing the cross.
NOTE: The brass cap must be located above
the center of the lower equalizing line, and the
long leg must face the boiler.
5. Assemble the blow-down valve into the bottom
port of the TC-L.
6. Assemble 1” NPT pipe plugs into the remaining
open port in both the TC-U and TC-L.
NOTE: The addition of the Test-N-Check valves
in place of standard crosses will extend the low
water cut-off approximately 2” farther from the
boiler.
7. Reassemble the low water cut-off and vertical
equalizing pipe to the upper and lower Test-N-
Check valves.
8. 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.
Installation of the TC-4 Test-N-Check Valve with an Existing Low Water Cut-off
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.
REMOVE CROSS
LWCO
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
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