BLACKMER XLW1 1/2, Installation, Operation And Maintenance Instructions

105-A00    Page 5/12 

OPERATION 

START UP PROCEDURES 

NOTICE: 

CONSULT THE "GENERAL PUMP TROUBLESHOOTING" 
SECTION OF THIS MANUAL IF DIFFICULTIES DURING 
START UP ARE EXPERIENCED. 

1.  Start the pump. Priming should occur within one minute. 
2.  Check the suction and discharge pressure gauges to see 

if the pump is operating within the expected conditions. 

3.  Check for leakage from the piping and equipment. 
4.  Check for excessive noise, vibration or overheating of the 

pump, reducer, and motor. 

5.  If possible, check the flow rate. 

6.  Check the pressure setting of the relief valve by briefly 

closing a valve in the discharge line and reading the 
pressure gauge. This pressure should be 20 psi (1.4 bar) 
higher than the maximum operating pressure.  

CAUTION: Do not run the pump for more than 10-15 
seconds with the discharge valve completely closed. 

If adjustments need to be made, refer to "Relief Valve 
Setting & Adjustment." 

Hazardous pressure 

can cause personal 

injury or property 

damage 

INCORRECT SETTINGS OF THE 
PRESSURE RELIEF VALVE CAN CAUSE 
PUMP COMPONENT FAILURE, 
PERSONAL INJURY, AND PROPERTY 
DAMAGE. 

FLUSHING THE PUMP 

NOTICE: 

IF FLUSHING FLUID IS TO BE LEFT IN THE PUMP FOR 
AN EXTENDED TIME, IT MUST BE A LUBRICATING, NON-
CORROSIVE FLUID.  IF A CORROSIVE OR NON-
LUBRICATING FLUID IS USED, IT MUST BE FLUSHED 
FROM THE PUMP IMMEDIATELY. 

1.  To flush the pump, run the pump with the discharge valve 

open and the intake valve closed.  Bleed air into the 
pump through the intake gauge plug hole or through a 
larger auxiliary fitting in the intake piping.  Pump air for 30 
second intervals to clean out most of the pumpage. 

2.  Run a system compatible flushing fluid through the pump 

for one minute to clear out the remainder of the original 
pumpage.  The valve in the discharge line should be 
restricted to build up 10 psi (0.7 bar) to force flushing 
liquid through the bearing seal chamber. 

3.  To remove the flushing fluid, follow step 1 above. 

NOTICE: 

AFTER FLUSHING THE PUMP SOME RESIDUAL FLUID 
WILL REMAIN IN THE PUMP AND PIPING. 
 

NOTICE: 

PROPERLY DISPOSE OF ALL WASTE FLUIDS IN 
ACCORDANCE WITH THE APPROPRIATE CODES AND 
REGULATIONS. 

PUMP RELIEF VALVE 

NOTICE: 

THE PUMP INTERNAL RELIEF VALVE IS DESIGNED TO 
PROTECT THE PUMP FROM EXCESSIVE PRESSURE 
AND MUST NOT BE USED AS A SYSTEM PRESSURE 
CONTROL VALVE.

XLW series pumps are fitted with an internal pressure relief 
valve that bypasses back to the suction side of the pump. 
 
Pumping volatile liquids under suction lift may cause 
cavitation. Partial closing of the discharge valve WILL result in 
internal relief valve chatter and is NOT recommended. For 
these applications, install an external system pressure control 
valve, and any necessary bypass piping, back to the storage 
tank. 
 
A system pressure control valve is also recommended when 
operating for extended periods (more than 15 seconds) 
against a closed discharge valve.

RELIEF VALVE SETTING AND 
ADJUSTMENT 

The relief valve pressure setting is marked on a metal tag 
attached to the valve cover. Generally, the relief valve should 
be set at least 15 - 20 psi (1.0 - 1.4 Bar) higher than the 
operating pressure, or the external bypass valve setting. 

DO NOT remove the R /V Cap OR adjust the relief valve 
pressure setting while the pump is in operation.  

1. 

To INCREASE the pressure setting,

 remove the relief 

valve cap, loosen the locknut, and turn the adjusting 
screw 

inwar

d, or clockwise. Replace the valve cap. 

2. 

To DECREASE the pressure settin

g, remove the relief 

valve cap, loosen the locknut, and turn the adjusting 
screw 

outwar

d, or counterclockwise. Replace the valve 

cap.  

Refer to the individual Blackmer pump parts lists for various 
spring pressure ranges.  Unless specified otherwise, pumps 
are supplied from the factory with the relief valve adjusted to 
the mid-point of the spring range. 

Hazardous pressure 

can cause personal 

injury or property 

damage 

INCORRECT SETTINGS OF THE 
PRESSURE RELIEF VALVE CAN CAUSE 
PUMP COMPONENT FAILURE, 
PERSONAL INJURY, AND PROPERTY 
DAMAGE. 

Hazardous or toxic 

fluids can cause 

serious injury. 

RELIEF VALVE CAP IS EXPOSED TO 
PUMPAGE AND WILL CONTAIN SOME 
FLUID