Troubleshooting and Maintenance of Air-Powered Pumping Systems

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1 Troubleshooting and Maintenance of Air-Powered Pumping Systems David Kaminski QED Environmental Systems Inc. Ann Arbor, MI / San Leandro, CA Copyright QED Environmental Systems, Inc. 2013; all rights reserved. The information contained within this document may not be published, broadcast, rewritten or otherwise distributed without prior written authorization from QED. Today s Webinar Topics Air-Powered Pump System Components Principles of operation how air-powered pumps work Diagnosing the problem: Look and Listen Common operational issues Safety considerations during pump maintenance Pump disassembly tools and tips Cleaning agents and tools Cleaning frequency and service life expectations Spare parts and spare pumps save time and $$$ Tips on pump removal and installation 1

2 2 Air Supply to Pump Air Exhaust Air Filter/Pressure Regulator Liquid Discharge Discharge Check Valve Pump Body Air Valve Mechanism Float Assembly Discharge Tube/ Float Guide Inlet Check Valve Inlet Screen Actuator Rod Automatic Air-Powered Pump Components Air-powered automatic pump: How it works Discharge Cycle When float reaches the top of its travel, exhaust valve closes and air inlet valve opens Air pressure against liquid closes inlet check valve and pushes liquid up discharge tube As liquid level drops, float follows and pulls actuator rod down, closing the air inlet valve and opening exhaust valve to repeat Fill Cycle Fill Cycle Hydrostatic pressure opens inlet check valve As pump fills with liquid, air escapes through exhaust valve and internal float rises

3 Normal Pump Operating Characteristics 1. Cycling you should hear a release of air pressure when the pump is cycling (exhaust cycle). 2. Pressure gauge if there is a filter/regulator at the well head, you can see a slight drop in the air pressure (5-10 PSI) with each pump discharge cycle 3. Cycle counter the cycle counter should advance a half count in the discharge cycle, then advance a full count with an audible click during the exhaust cycle What if my pump isn t cycling? Determine if the issue is the operating conditions in the well or a pump malfunction Examples of operating conditions: Very low well yield (will eventually cycle check counter) Liquid level has dropped below actuation point Air supply pressure insufficient for discharge Excessive discharge line back pressure Examples of pump malfunction Float sticking due to solids buildup, slime, silt Check valve not working due to debris, sand Air valve mechanism plugged or out of adjustment 3

4 First Step: Look and Listen Look at the well head and connections for an obvious problem broken fittings or connections, tubing kinks, etc. Listen for an air leak from a fitting or line at the well head Look at the air pressure gauge for low or no pressure Listen for a continuous discharge condition you ll hear a hissing sound coming from the pump exhaust line (may be above or below well cap) and/or the liquid discharge line Pump stuck in discharge mode Continuous air coming out of the exhaust line can indicate that the pump is stuck in discharge mode and can t switch back to the refill mode The float may be stuck due to sticky or solid buildup on the discharge tube or debris inside the pump Cleaning will most often resolve the problem 4

5 Pump stuck between cycles If the pump is stuck between cycles, both the air inlet and exhaust poppet valve will be open, allowing air to pass continuously out of the exhaust port and possibly through the discharge line Additional evidence: the cycle counter may be stuck between cycle counts Possible causes include an air valve mechanism that is worn or out of adjustment, a worn pivot pin or air valve lever half bushing Cleaning, adjustment or repair may be required to resolve the problem Is liquid level above actuation point? To determine if you have sufficient liquid over the pump to actuate the air valve, you need to know: The installed depth of the pump The pump model and its actuation point The liquid level in the well/riser If the liquid level is above the actuation point and air pressure is sufficient to overcome total discharge head, there is a problem with the pump, such as a stuck float, debris, actuator rod issue, air valve issue, etc. 5

6 Pump Actuation Point The point at which the liquid level inside the pump activates the air valve mechanism is called the actuation point The actuation point is the distance from the bottom of the pump to the top of the float travel (top of inlet on top-fill pumps) This distance varies based on pump body length, float length and inlet position and is specified for each pump model The pump position in the well determines the maximum drawdown level in the well Determining the liquid level Liquid level can be measured manually with a water level tape/meter or with a dedicated level measurement system (e.g., bubbler or transducer system) Water level tape/meter has a lower capital cost but requires the well to be opened and takes more time Dedicated level measurement systems cost a bit more (as little as $100 per well) but save enough labor to pay for themselves quickly 6

7 7 Liquid Level Measurement Options Bubbler tube level systems Manual measurement with sounder Digital Level Meter with Easy Level System How vacuum affects the pump actuation point A vacuum applied to the well (e.g., landfill gas collection, vapor extraction) will RAISE the actuation point above the design point when the pump exhaust is outside the well The increase in the actuation point is based on the amount of vacuum applied to the well, measured in inches (centimeters) of water column (WC) In the example, a vacuum of 20 (51 cm) WC raises the actuation point of the pump from 33 (84 cm) to 53 (135 cm)

8 How to check if vacuum is preventing the pump from cycling 1. Install a level tape in the well or activate your dedicated level measurement system 2. Turn off the vacuum at the well head 3. Measure/watch the liquid level and wait for it to begin dropping 4. If the pump starts cycling at the design actuation point, the problem is insufficient submergence under vacuum Lower the pump in the well/riser if possible If exhaust is outside well, change to inside well or install an equalization valve Pump stalling due to insufficient air pressure at the well head A pump can stall if the air pressure is too low to lift the liquid to the well head and/or overcome header line back pressure Air-powered pumps need a minimum of 0.5 PSI air pressure for every foot of lift desired plus 1.0 PSI for every PSI of back pressure in the header line Test for low air pressure: increase pressure at well head in 5 PSI increments; pump will start cycling if pressure was too low to overcome lift requirement Test for high header line back pressure: disconnect the discharge line at the header and direct it back into the well; pump will start cycling if pressure was too low to overcome header back pressure 8

9 9 How to jump start your pump Sometimes a quick jump start can get the pump cycling again when it stalls or is stuck in discharge Remove the air line from the filter/regulator, allow all the air to exhaust from the pump, then reconnect the air line; pump should cycle if sufficiently submerged Another jump start is to unbolt the well cap and shake the pump/tubing to dislodge the float If the jump start method gets the pump cycling again, it s a good indication that the pump needs to be cleaned or serviced to maintain consistent operation and maximum performance Cleaning air-powered pumps

10 10 Determining cleaning frequency Cleaning frequency is determined on a site-by-site basis. Some sites may go as long as a year without having to pull and clean the pumps, while others may require cleaning as often as monthly or more To gauge this, pull the pumps after the first quarter of use, or after the first month at sites with a history of oily deposits, highly mineralized leachate, etc.; subsequent checks will indicate trends Managing High Dissolved Solids Build-Up Sites with highly mineralized leachate often have problems with precipitation and solids deposits on pump components and discharge tubing/pipes QED has developed an automated system to blow down any AutoPump to minimize solids build-up and maintain steady pump operation Air is blown down the exhaust line of the pump through a solar-powered control valve and into the discharge line; exhaust air can still escape through a quick-dump valve above the cap/flange Wells that required maintenance weekly or more have been in operation for two months without maintenance

11 Model C230 AutoBlast System Components Pump maintenance safety considerations Most important make sure the pump and all lines are not pressurized before you begin any disassembly! Wear appropriate safety gear Safety glasses with side shields or a full face shield Protective outer clothing (e.g. Tyvek jump suit) Chemically resistant gloves taped at top to prevent leaks Reflective high-visibility vest or coat Hard hat 11

12 Shut-offs, check valves and lines Shut off any valves air supply, discharge header Release all the air pressure from the pump If the pump discharge tubing is filled with liquid, you can lighten your load using the QED Pump Blow-Out Kit (Part Number shown here) to empty the lines Lifting the pump and tubing Wear protective gloves and get a good grip on the tubing or hoses Try to avoid getting kinks in tubing kinks tend to be permanent and can restrict flow or create leaks Use your legs, NOT YOUR BACK! Use a step ladder or tailgate to gain some height and leverage If the system is too heavy, use a winch or crane 12

13 Well head tubing rollers If possible, use a well head tubing roller mounted to the edge of the well casing or flange to simplify pump removal and avoid tubing kinks Pull the tubing into the roller and walk it out of the well less stress on legs, back and shoulders Well head tubing rollers Tubing roller on flange well head Tubing roller for casing edge 13

14 Keeping debris out of air lines Debris in air lines (dirt, insects, etc.) can clog filter regulators and plug pump air valve poppets Blow out air header lines before connecting pump air supply hoses Cap or tape end of tubing after pulling the pump to avoid debris Easy Fittings Faster and Safer Cutting tubing and clamps off barb fittings can be difficult, time consuming, poses a safety risk, and shortens tubing length 2-3 (5-8 cm) Easy Fittings are high-flow quick connects with quick-release retainer clips Made of high-quality stainless steel alloys with double Viton O-ring seals Saves valuable field time and cost LESS than conventional quick-connect fittings 14

15 Automatic air-powered pump components Discharge Head & Air Valve Assemblies Discharge Tube/Float Guide Pump Body Float Assembly Actuator Rod Inlet Check Valve Assembly & Screen Get the right tools QED offers a complete tool kit for AP4 pumps Pipe vise with rubber jaws to hold pump body Double pin spanner to remove threaded inlet Honing tool to remove hard deposits from pump body Casing removal tool, punch and Allen wrench What about tools for the AP4 Plus? The newly redesigned AP4+ has a bottom inlet design that comes off easily by removing three small bolts no need for the spanner or casing tool! The honing tool and pipe vise (if desired) can be purchased separately 15

16 AP4 Service Tool Kit Cleaning agents and tools Degreasing agents such as Simple Green or Detergent 8 can remove oily or slimy deposits Scouring pads can remove about 90% of biogrowth and buildup on pump parts Brush kits with extended handle to clean inside the pump body and discharge tube 16

17 Cleaning agents for scale buildup Acid cleaning solutions such as CLR or common acids such as vinegar (acetic acid), citric acid, muriatic (hydrochloric) acid can help remove heavy mineral deposits and biorock Do not leave metal parts in strong acids overnight! Don t clean acetal (Delrin ) plastic parts with acids it can weaken/damage them NEVER mix acids with other cleaning solutions ALWAYS rinse other cleaners away first to avoid dangerous (and potentially fatal) chemical fumes Air Valve Mechanism Adjustment The air valve mechanism should not require adjustment unless it has been repaired or has some wear from long-term use If adjustment is necessary, contact QED for information and instructions based on pump model Air Valve Out of Adjustment (Gap between valve mechanism and pump head) After Proper Air Valve Adjustment 17

18 Stand tubes for pump testing A stand tube should be used to verify that a pump is working before you send it back down the well to avoid pulling it again if it s still not working You can make a stand tube from a piece of 4-inch diameter PVC pipe or well casing about 5 feet long, with a flat threaded cap or plug at the bottom PVC is very inexpensive, holds up well to most cleaning solutions and leachates A stand tube can save HOURS of time lost if a pump isn t working before it s installed Pump service life expectations Pump service life is dependent on operating conditions of each well (chemistry, temperature, solids, etc.) and proper materials selection for the application The biggest factor you can control is pump maintenance. Many QED pumps have been in use for years and are still operational due to regular maintenance 90% of all pump maintenance is cleaning, not repairs 18

19 Spare parts for field repairs Spare parts needed will vary by pump model, but most require only a handful of parts The quantity of spare parts you will need is dependent on the size of your site and how many pumps you have QED Customer Service can help you with recommended parts for your pumps, such as check balls, O-rings, fittings and springs Spare pumps = major cost savings When field labor for cleaning or repairs exceeds minutes, having one or more spare pumps can save considerable cost over immediate field repair Less downtime, especially valuable in LFG wells Repairs can be done in the shop or by the manufacturer rather than under field conditions No worries about having the necessary spare parts Shipping cost for parts or pump repairs can be done at standard rates rather than overnight shipping 19

20 Replacement tubing pre-cut or bulk? You can either have the tubing pre-cut at the factory, or have it shipped in bulk rolls Method A: Precut by QED we provide spec sheets showing installed depth based on your well data Method B: Measure out and cut bulk tubing at the site so the inlet is at the proper location down well and the installed depth can be recorded Method C: Measure depth of well from top of casing, connect tubing to pump, lower to bottom of well, raise desired amount (1 foot or more), subtract this from well depth to determine and record inlet depth Additional Installation Tips When installing pumps it is best to have the air system and discharge headers installed so the pumps can be operated immediately If the pumps need to be installed before air and discharge headers, QED recommends sealing the pump exhaust line before installation to prevent the pump from filling with liquid, which can minimize corrosion, and debris from clogging air valve poppets 20

21 21 Some applications are a bit more challenging than others, but with proper pump model and material selection, good installation practices and adequate maintenance, air-powered automatic pumps can handle some of the toughest pumping application seen at landfill and remediation sites Questions? David Kaminski QED Environmental Systems, Inc. info@qedenv.com Toll-Free Numbers Ann Arbor, MI: San Leandro, CA: Websites