Pump Performance Checklist
provided by Gorman-Rupp Pumps

 

     Whether you use your pumps for agricultural, construction, industrial or sewage applications, keeping them in shape can help reduce costs and boost profits by cutting fuel consumption, reducing parts replacement costs and minimizing pumping time on every project.
     A pump that lets you down when you need it most causes obvious losses of time and money. Not so obvious, but every bit as costly, are losses you can incur with pumps that operate at less-than-peak efficiency. 

   A pump laboring under the handicap of a suction line air leak, a corroded discharge line or a clogged impeller gulps excessive amounts of energy, takes longer than necessary to do the job, and subjects parts to undue stress, causing premature wear-out.
 
How High Can The Losses Run?
     A 6-inch gasoline-driven, self-priming centrifugal pump operating at 25% less than peak efficiency through an 8 hour day uses approximately 8.8 gallons more fuel than a pump which is operating efficiently.
     At $1.10 per gallon over a 40 hour week that's $48.40 per week LOST! and that figure doesn't include added personnel costs.
     Multiply the possible hidden losses by the number of pumps you have in operation and you see why it pays to keep your pump in top working order.
     We want to keep your pump efficient. There's really no reason to let them deliver less than their best.
A 9-Point Helpful Checklist, Courtesy of Gorman-Rupp Pumps
     We prepared it because today every penny of profit counts, and we want your pumps to work for all they're worth.
Centrifugal Pumps
     Look for these signs of inefficiency. Indications that your pump is costing you more to operate than it should may not be dramatic but they're easily recognized.
     You know you're being short-changed if... 
  • THERE'S A NOTICEABLE DIFFERENCE IN PUMP FLOW.
         Has the discharge flow visibly decreased? Is it taking your pump longer than it used to to do the same job? The slow-up might be caused by a collapsed suction hose lining, a leaking gasket, plugged suction line, a damaged or worn impeller or wear plate.
  • YOUR PUMP ISN'T REPRIMING AS RAPIDLY AS IT ONCE DID.
         Is the seal leaking, is all hardware at gaskets tight, is the suction check valve sealing properly, is the cut water section of volute badly worn or recirculating port clogged? 
  • YOUR PUMP IS MAKING EXCESSIVE NOISE.
         Does it sound like a bunch of marbles rattling in a can? This may be cavitation and could be caused by too high of a suction lift, too long a suction hose, a clogged strainer or collapsed suction hose lining, plugged suction line or combination of all these. Maybe the bearings are going out.
  • YOUR PUMP IS CLOGGING FREQUENTLY.
         The suction check valve may be clogged, and improper strainer may be too large or small, or the strainer may be in mud plugging the suction side.
  • YOUR PUMP IS OVERHEATING
         Very likely the flow of liquid into or out of the pump is being restricted. Improper impeller clearance could be slowing repriming or the suction strainer may be clogged.

General Pump Diagram
Use this Checklist to Improve Pump Performance . . . and Profits
     Although this list is not a complete guide to pump inspection and service, it does cover the more common conditions that can impair pump efficiency.
SUCTION LINE
  1. Check for air leaks. Using a vacuum gauge, make sure that the suction line, fittings and pipe plugs are airtight. Most pumps have a tapped hole for easy connection of a vacuum gauge. Use pipe dope to seal gauge threads and pipe plugs. Replace leaky seals and badly worn hoses.
  2. Check the suction hose lining. The rubber lining in a suction hose can pull away from the fabric, causing partial blockage of the line. If the pump develops a high vacuum but low discharge, the hose lining may be blocking suction flow. Replace hose.
  3. Check the suction strainer. Frequent inspection and cleaning of the suction strainer is particularly important when pumping liquids containing solids. Proper size strainer should prevent pump from clogging.
PUMP
  1. Check impeller vanes, wear plate or wear rings.The removable cover plate on many pumps permits quick, easy inspection of the impeller and wear plate. These components should be inspected every six months or sooner, depending on pump application. They're subject to faster wear when pumping abrasive liquids and slurries. Wear plates and wear rings can be replaced without replacing expensive castings.
  2. Check impeller clearance. If the clearance between impeller and wear plate or wear rings is beyond recommended limits, pumping efficiency will be reduced. If the clearance is less than that recommended, components will wear excessively. If tolerances are too close, rubbing could cause an overload on the engine or motor. Check the impeller clearance against pump manual specifications and adjust if necessary.
  3. Check the seal. Most pumps are equipped with a double seal lubricated under pressure - with a spring-loaded grease cup or an oil lubricated tungsten titanium carbide seal for long, trouble-free service. If your pump has a single seal and it is lubricated with the water being pumped, sand and other solids can cause rapid wear. Check and replace the seal if worn. Replace seal liner or shaft sleeve if it has scratches.
  4. Check bearings. Worn bearings can cause the shaft to wobble. Eventually the pump will overheat and sooner or later it win freeze up and stop. Replace bearings at the first sign of wear.
  5. Check the engine or motor. The pump may not be getting the power it needs to operate efficiently. The engine may need a tune-up or the motor may need service.
DISCHARGE LINE
  1. Check operating condition. Check air release devices, valves, check valves and shock control devices for proper operation. Old discharge lines are subject to internal rusting and pitting, which cause friction loss and reduce flow by as much as 15%. Replace badly deteriorated line.

Centrifigal Pump Diagram
A Word about Submersible and Diaphragm Pumps
     If your submersible pump operates but at a reduced capacity it could be caused by a worn impeller, excessive impeller clearance, low or incorrect voltage or it could be running backwards. Too high of a discharge head, a clogged or kinked hose or a clogged strainer could also be responsible for reduced flow. Use an amp meter and volt meter to determine if the pump is getting the proper power it needs to operate efficiently. Amp readings are in the operation manual.
     If your diaphragm pump isn't pumping as it should check diaphragm, suction and discharge check valve flappers and seats; replace if worn. Check suction hose and fittings for leaks. Check plunger rod for proper adjustment.

 

Return to the Pumps Reference Articles Index
© Copyright 2007 Maintenance Resources, Inc.
Phone: 812.877.7119  -  Fax: 812.877.7116  -  E-Mail: info@maintenanceresources.com
Address: 1983 North Hunt Street  -  Terre Haute, IN 47805