Xylem MM 315E Models 51, 51S and 53 Boiler Water Feeders Models 51-2, 51-S-2 and 53-2 Feeder Cut-Off Combinations - Manual (Page 7)

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The following is intended as a guide to determine why the feeder may not be operating as intended. Please note that
there can be system and installation issues that can affect the operation of the feeder. This includes but is not limited to
the following:
• Piping not installed properly
• Priming and foaming of boiler water
• Faulty check valve in return header • Delay in condensate returning to boiler
• Tankless coil leaking
TROUBLESHOOTING
B
A. Using a 1/2" wrench, unscrew the four (4) hex-head
bolts (B) that secure the strainer.
B. Clean any debris (scale, rust, etc.) from strainer.
Replace if debris cannot be removed.
C. Re-install strainer.
Series 51-S/53
Removal of strainer for inspection and cleaning
Boiler is getting too much water.
a) Cause: The valve is not shutting off.
Test: Perform broken union test.
Solution:
• Series 51 Feeders Only: Remove and inspect
cartridge. Clean or replace as necessary.
• Series 51-S and 53 Feeders Only: There may be
debris lodged in the valve preventing it from closing
completely. Remove and clean valve assembly.
Replace if necessary.
b) Cause: By-pass valve is leaking.
Test: Perform broken union test.
Solution: Repair or replace valve.
c) Cause: Float chamber clogged with sediment.
Test: Open blow-down valve. If there is little or no
water flow, the chamber may be clogged with sediment.
Solution: Remove head assembly from float chamber
and clean sediment from chamber, float and bellows
mechanism. Replace head mechanism if necessary.
d) Cause: Float has filled with water.
Solution: Replace float.
e) Cause: Equalizing piping is plugged.
Solution: Clean or replace piping.
f) Cause: City water supply is above 150 psi (51, 53
Feeders) or 100 psi (51-S Feeder).
Solution: Install pressure reducing valve to reduce
water pressure.
Boiler is not getting enough water.
a) Cause: There is something preventing the valve from
fully opening.
Test: Perform broken union test.
Solution:
• Series 51 Feeders Only: Remove and inspect
cartridge. Clean or replace as necessary.
• Series 51-S and 53 Feeders Only: There may be
debris lodged in the valve preventing it from closing
completely. Remove and clean valve assembly.
Replace if necessary.
b) Cause: Strainer clogged with sediment.
Test: Perform broken union test.
Solution: Remove and inspect strainer. Clean or
replace as necessary.
c) Cause: Float chamber clogged with sediment.
Test: Open blow-down valve. If there is little or no
water flow, the chamber may be clogged with sediment.
Solution: Remove head assembly from float chamber
and clean sediment from chamber, float and bellows
mechanism. Replace head mechanism if necessary.
d) Cause: Feed line between valve and boiler is partially
plugged.
Test: Perform broken union test. With union broken,
there should be water flowing through the piping from
the boiler.
Solution: Clean or replace piping.
e) Cause: Feed line between valve and city water supply
is plugged.
Solution: Clean or replace piping.
f) Cause: Water supply pressure less than boiler
pressure.
Solution: Reduce boiler pressure or convert to pumped
return.