I’ll try to be thorough as to not leave many questions, hopefully someone is familiar with our above ground tank set up. I am not an engineer but rather a mechanical tech, trying to resolve a problem with our above ground tank diesel dispensing set up. Our company engineers are clueless... We have two 9,900 gal. diesel tanks, arctic climate (-40 to 70 deg F year round) supply for the dispenser (gasboy 9153K) comes off the bottom of the tank to a manual gate valve, then to a butterfly valve with a solenoid that is dispenser controlled(actuates when dispenser pump is turned on/off) then to a Tokheim Model 52 pressure regulating valve, then the sheer valve and dispenser. Total length of piping is not long, maybe 30', 2" dia. i believe. The problems we are having are leakage from every gasketed surface of the pump and nozzle. Nozzles fail regularly, and most recently we had a spill from the dispenser pump air separator vent. After some research, i found that the Model 52 pressure regulating valve we have installed still has the blue shipping plug installed on the atmospheric vent (no vent line installed higher than tank level) This could definitely be the cause of the spill from the air separator vent line. My understanding of the air separator on the pump is incomplete at best. Initially i thought that the leakage problem was being caused by thermal expansion downstream of the PRV (dispenser side) which does contain an internal thermal relief for any pressure that builds UP stream of it, and is supposed to bleed through the pumps air separator vent line. In the trouble shooting section of the Model 52 PRV it clearly states that failure of the valves diaphragm or specifically not removing the blue shipping plug can cause release of fuel through the pumps air separator line, no mystery there. After researching this further though the mystery for me is why are we having so many leaks that initially I attributed to thermal expansion within the pump, not understanding that the pressure could vent itself downstream of the Model 52 PRV out the pumps air separator vent. Ambient temp for the past two months during this problem have been around -20 to 20 above F. Fuel from the tanks is at ambient, and the dispenser is enclosed and sometimes heated to around 80 deg. F. (some think that will fix our problem and I keep telling them it is making it worse!!) Any input would be greatly appreciated. I contacted the local vendor and their “expert” is out of state for a week. Thanks.
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