top of the toroid. This condition usually is 

 caused by tlie pumping rate Ijeing too fast or 

 the sample cell not being "wetted" (see par. c). 

 When filling cell to assure proper pump rate, 

 adjust Fill knob until tlie proper pump rate is 

 obtained. Or, if the latex rubber tube is on the 

 air relief inlet (Step 3, par. 1-19), adjust the 

 screw clamp until proper pump rate is attained. 



c. Air is being entrapped bex?ayse of a dirty 

 sample cell or toroid, or the inside of the sample 

 cell is not "wetted.'' If the inside of the cell is 

 visibly dirty or if excess grease can be seen on 

 the inside of the cell, disassemble the cell as 

 described above in la (2) (a). Observe the cau- 

 tion about damaging the platinnm resistance 

 thermometer. Carefully wipe off the inside of 

 the cell bowl, the inside top of the sample cell, 

 and the toroid with a lab tissue. Make sure that 

 any visible vacuum or stopcock grease is re- 

 moved. Check the alinement of the toroid as- 

 sembly with the platinum therometer as de- 

 scribed in 'b(l) above. Reassemble the sample 

 cell.ivs described in la(2)(b), again observing 

 caution about possible damage to the 'platinum 

 thermometer. Fill the cell with a wetting agent 

 solution such as Tergitol or Cutscum, prepared 

 by taking 1 part wetting agent to 20 parts of 

 lukewarm water. Shake to hasten solution. Turn 

 on the stirrer and allow wetting agent to remain 

 in the cell for 5 minutes. Drain the cell and rinse 

 with fresh water several times. Allow the 

 sample cell to come to room temperature, es- 

 pecially if lukewarm solution was used (this 

 may take several hours) before running any 

 salinity determinations. This treatment usually 

 is very effective and should be done about once 

 a week if the salinometer is in constant use. The 

 solution of wetting agent can be used over and 

 over again. 



2. Sample cell cannot be filled. Failure of the 

 pumping assembly can be traced to one or more 

 of the following causes : 



a. Overflow jar is not tight. Grease overflow 

 jar threads with stopcock grease. Make sure jar 

 is properly placed and tightened to the over- 

 flow jar lid. 



b. One or more of the hose connections are 

 not tight. Remove the RS-7A salinometer 

 chassis from the case by taking off the seven re- 

 taining screws along the top and bottom of the 

 front panel. On newer models, remove the rear 

 cover. Loosen the pump clamps. Pull out the 

 pump. Check all of the hose connections to make 

 sure they are tight. 



c. Rubber hose is pinched somewhere in the 

 system. Check all rubber hoses to make sure that 

 they are not pinched or bent sharply, closing off 

 a part of the pumping system. This could mean 

 shortening or lengthening one or more of the 

 hoses. 



d. Ball check valve is not operating or tem- 

 porarily stuck or direction was erroneously re- 



versed during installation. The ball check valve 

 of the pumping system is located in line of the 

 hose that connects the pump cylinder to the 

 overflow jar. Disconnect this hose from the 

 pump cyclinder and the overflow jar. Remove 

 the check valve by pulling the hose apart. This 

 valve should be constructed of a stainless steel 

 sleeve and a Teflon ball. If not, replace with this 

 type. Make sure the ball is loose in the sleeve. 

 Should it be frozen, clean with fresh water and 

 dry. If still frozen, replace. Reinstall the check 

 valve in the black rubber tubing, connect to the 

 pump cylinder and overflow jar. Make sure the 

 ball end of the stainless steel sleeve is toward 

 the pump cylinder; otherwise, the system will 

 not operate. 



e. Leather cup washer on the bottom of pump 

 piston is worn out or has pulled away from the 

 inside of the cylinder wall. Loosen the screw 

 near the slot atop tJie piston. Loosen the screw 

 that holds the pump cylinder to the pump motor 

 frame. Remove the cylinder and the piston as- 

 sembly. Pull out the piston. Remove the screw 

 that holds the leather cup washer to the piston 

 shaft. Replace the cup washer with a new one, 

 but first massage the new washer with motor 

 oil. Reassemble and aline the pump cylinder 

 properly, making sure the piston shaft does not 

 touch the cylinder when the pump flywheel is 

 turned (by hand) a complete revolution. Do not 

 tighten the screw near the piston slot too much 

 or the bearing will freeze; too loose an adjust- 

 ment will cause a knocking noise. 



f. Pump motor belt is loose, worn and slip- 

 ping, or is too tight. If the pump belt looks 

 worn, replace it. If the pump belt is too tight 

 the motor will not start the pump. If it is too 

 loose, the pulley or flywheel will slide under the 

 belt. For proper tension, loosen the two motor 

 mount nuts on the pump motor frame and move 

 the motor to the right or left to obtain proper 

 spacing. Retighten the mounting nuts. Several 

 trials may be necessary to insure proper belt 

 tension. 



g. Pump bearings or motor needs lubrication. 

 Lubricate each of the oil points with two drops 

 of about #SAE SOW motor oil. Wipe off any 

 excess or spilled oil. 



h. Large air leak from outside the sample 

 cell. Follow procedures outlined in la (1) 

 through (6). 



3. Stirrer does not operate. 



a. Belt from motor stirrer pulley is loose or 

 worn. Replace belt. 



b. Stirrer sticks or stirrer speed is erratic 

 and/or not consistent. 



(1) Make sure stirrer pulley set screws are 

 tight. These screws may be slotted or Allen- 

 type. If stirrer still sticks or is erratic, proceed 

 as follows : 



(a) Remove the six screws and remove 



the cell bowl. 



1-19 



