Blagdon Pump AVB75 Metallic - Manual (Page 10)

avbmdl1sm-rev0111 Model AVB Metallic Page 8
PUMP TROUBLESHOOTING
CAUTION! WHENEVER TROUBLESHOOTING OR PERFORMING ANY
REPAIRS ON ANY BLAGDON EqUIPMENT, ALWAYS REMOVE THE AIR
SUPPLY LINE TO THE PUMP AND WEAR PROPER PERSONAL PROTECTIVE
EqUIPMENT.
PUMP WILL NOT CYCLE
What to Check: • The system head exceeds the air supply pressure to the pump.
Corrective Action: • Increase the air inlet pressure to the pump. Most diaphragm pumps are
designed for 1:1 pressure at zero flow.
What to Check:• Check ESADS+, including pilot valve assembly and main air valve assembly.
Corrective Action: • Disassemble and inspect the main air distribution valve, pilot valve, and
pilot valve actuator pins. Check for scores, wear, or damaged o-rings. Replace parts as necessary.
Refer to the exploded view drawing and air valve section (P.18 & 20).
What to Check: • Blocked discharge line.
Corrective Action: • Check for obstruction or closed discharge line.
What to Check: • Blocked pumping chamber.
Corrective Action: • Disassemble and inspect wetted chambers of the pump. Remove or flush
any obstructions. Refer to page 14 for disassembly.
PUMP CYCLES, BUT WILL NOT FLOW OR FLOW RATE IS UNSATISFACTORY
What to Check: • Restricted or undersized air line.
Corrective Action: • Make sure there are no obstructions or restrictions in the air inlet to the
pump. Install proper size air line and/or air line equipment. Refer to air supply section (p.7) air inlet
plumbing recommendations.
What to Check: • Restricted or undersized suction piping.
Corrective Action: • Make sure there are no obstructions or restrictions in the suction line or
related suction components such as screens or strainers. Install the proper size suction line and/
or equipment. It is recommended that any suction line components and pipe size be at least the
same size as the suction line thread size to the pump. Though best results will always be realized
if the line size of the suction line is increased by one size. Refer to the installation section (p.5) for
recommended suction plumbing recommendations.
What to Check: • Blocked air exhaust muffler.
Corrective Action: • Remove muffler, clean or de-ice and reinstall.
What to Check: • Excessive Suction Lift.
Corrective Action: • For lifts exceeding 20 feet (6 meters), filling the pump chambers with liquid
will prime the pump in most cases. If not, place pump closer to fluid level.
What to Check: • Suction line cavitation.
Corrective Action: • If no obstructions are in the suction line of the pump, decrease the inlet
air pressure and/or volume to the pump. This will slow down the diaphragm speed and reduce the
cavitation.
What to Check: • Partially blocked exhaust muffler.
Corrective Action: • Remove muffler and make sure that some of the material being pumped has
not migrated into the muffler element. If it has, replace the element or clean it and reinstall. If product
has made it to the muffler, then the diaphragm assembly will need to be inspected. Refer to the
Diaphragm Replacement section (p.15).
What to Check: • Suction side air leakage or air in the product.
Corrective Action: • Visually inspect all suction side gaskets, seals, as well as pipe and pipe
connections.
PUMP CYCLE SEEMS UNBALANCED OR PRODUCES EXCESSIVE VIBRATION
What to Check: • Excessive flooded suction in system.
Corrective Action: • Check height of fluid above pump. For flooded conditions, exceeding 10 feet
(3 meters) of liquid, install a back pressure device in the exhaust side of the pump.
What to Check: • Worn or misaligned check valve or check valve seat.
Corrective Action: • Disassemble the wet end of the pump and inspect check valves and seats
for wear and proper seating. Replace them if necessary. Refer to the Check Valve section (p.15) for
disassembly instructions.
What to Check: • Obstructed check valves.
Corrective Action: • Disassemble the wet end of the pump and look for obstructions that may
prevent the check valve from seating on the seat. Look for damage on the valve and the seat. Replace
them as necessary. Refer to the Check Valve section for disassembly (p.15).
What to Check: • Rigid pipe connections.
Corrective Action: • Install flexible pipe isolators or expansion joints between the plumbing and
the pump.
What to Check: • Pulsation in the discharge line.
Corrective Action: • Excessive pulsation in the discharge line may be corrected by installing a
Tranquilizer Surge Suppressor.