Xylem MM 802F User Manual
Model TC-4
Test-N-Check®Valves
For Hot Water Boilers
Does in minutes what used to
take hours.
INSTRUCTION MANUAL
MM-802F
Applications:
For isolation of equalizing lines during low
water cut-off testing.
OPERATION
Maximum Operating Pressure: 160 psi (11 kg/cm2)
Maximum Operating Temperature: 250˚F (121˚C)
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• Before using this product read and understand instructions.
• Save these instructions for future reference.
• All work must be performed by qualified personnel trained in the proper application, installation, and maintenance of plumbing, steam, and electrical equipment and/or systems in
accordance with all applicable codes and ordinances.
• To prevent serious burns, the boiler must be cooled to 80˚F (27˚C) and the pressure must be
0 psi (0 bar) before servicing.
TC-U Upper Valve TC-L Lower Valve
WARNING
• To prevent serious personal injury from steam blow-down, connect a drain pipe to the control
opening to avoid exposure to steam discharge.
California Proposition 65 warning! This product contains chemicals known to the
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state of California to cause cancer and birth defects or other reproductive harm.
Previous controls should never be installed on a new system. Always install new
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controls on a new boiler or system.
Failure to follow this warning could cause property damage, personal inj ury or death.
CAUTION:
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A more frequent replacement interval may be necessary based on the condition of
the unit at time of inspection. McDonnell Miller s warranty is one (1) year from date
of installation or two (2) years from the date of manufacture.
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Simplify Testing of Low Water Cut-offs on Hot Water Boilers
TEST-N-CHECK®VALVES
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.
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 discharged causing burns.
Failure to follow this caution could cause personal injury.
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CAUTION
TEST-N-CHECK VALVES
SIMPLIFY TESTING OF LOW WATER CUT-OFFS
ON HOT WATER BOILERS
Good operating practice requires installation of a low
water cut-off on a hot water boiler and that it be
checked regularly to make certain the control will
function properly in the event of a low water condition.
Boiler owners and installers need a quick and efficient
way to test a low water cut-off on a hot water boiler.
Simply opening a blow-off valve below the float
chamber may not serve as a valid test and is excessively
wasteful of boiler water and fuel. The water
level in the float chamber, and the float, must drop far
enough to start the control through its cycle of operation.
However, water flowing in through the equalizing
piping may replenish the level in the float chamber fast
enough to delay the necessary float drop, or prevent it
altogether.
McDONNELL & MILLER Test-N-Check Valves have
been specially designed for such installations. In normal
operation, they allow free circulation of water through
the equalizing piping and float chamber. But any sudden
onrush of water, such as caused by opening the blowoff,
snaps shut a damper in each valve to restrict flow
to the float chamber. Water level in the float chamber
falls quickly to start the control through its operating
cycle, with a minimum loss of boiler water. When
blow-off is closed, dampers return to normally open
position.
McDONNELL & MILLER Test-N-Check Valves simply
replace the crosses above and below the control in the
equalizing lines. Valves have the same dimensions as
standard crosses and nipple in the horizontal leg, and
allow normal rod clean-out of pipe in both directions.
Connections are 1" NPT female tappings.
Upper and lower valves are identical, except that the
upper valve has vacuum breaker built in to allow for
rapid evacuation of the float chamber. They are furnished
in sets-one upper and one lower valve, to
equip one equalizing line. They can be used with all
McDONNELL & MILLER Low Water Cut-Offs for hot
water boilers.
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