CO Well Driller flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Grout water ratio

Neat cement grout uses no more than 6 gallons of clean water per 94-lb sack to keep slurry dense enough to seal the annulus and resist shrinkage and cracking.

Tremie placement

Grout is pumped through a pipe whose discharge end stays submerged in the rising grout column, placing seal material from the bottom up without voids.

Minimum grout annulus

The annular space between borehole wall and casing must be at least 2 inches thick so the seal performs as designed; thinner annuli fail to meet rule.

Sanitary well seal

A watertight, vermin-proof cap or seal at the casing top that excludes surface water, insects, and debris while allowing venting and access to the well.

Well yield test

A pump or bailer test, commonly 8 hours, that records static level, pumping level, drawdown, and recovery so sustainable yield can be documented on the well log.

Setback distances

State minimum horizontal separations, typically 50 ft from septic tanks and sewer lines and 100 ft from drainfields, protect the well from contamination sources.

Thermally enhanced grout

Bentonite or cement grout blended with silica sand or graphite to raise thermal conductivity, improving heat transfer between loop pipe and formation while sealing the borehole.

Grout volume per foot

Annular volume equals borehole area minus pipe area; a 5-inch hole with 1.25-inch pipe holds about 0.11 cubic feet of grout per linear foot.

Loop pressure test

The closed-loop pipe is pressurized to 1.5 times maximum operating pressure, at least 100 psi, and held 15 minutes before grouting and again before trench backfill.

Thermal response test

An in-situ test that circulates heated fluid through a test borehole to measure formation thermal conductivity and borehole resistance for accurate loop-field sizing.

Borehole spacing

Vertical loop boreholes are commonly spaced 15-20 ft apart to limit thermal interference between adjacent boreholes over the life of the system.

Abandoned borehole grouting

Unused or failed loop boreholes must be grouted full length with low-permeability grout to prevent aquifer cross-connection and vertical groundwater movement.

Pump setting depth

The submersible pump is set below the pumping water level and at least 5-10 ft above the screen or well bottom to avoid cavitation and sediment intake.

Pump capacity versus yield

A pump rated above well yield lowers the water level to the intake, causing cycling, overheating, and motor failure; capacity must not exceed sustainable yield.

Pressure tank precharge

Air charge in the tank is set 2 psi below the pump cut-in pressure, for example 28 psi for a 30/50 pressure switch, to maximize drawdown.

Total dynamic head

TDH equals static lift plus drawdown plus friction loss plus discharge pressure head; pump selection uses TDH and required flow on the pump curve.

Voltage drop limit

Conductor sizing keeps voltage drop on the pump circuit under 5 percent, using manufacturer ampacity and distance tables rather than generic wire charts.

Pitless adapter

A fitting that carries the service line through the casing below frost line, allowing the drop pipe to be removed without excavating the service line connection.

Torque arrestor

A rubber device on the drop pipe that cushions starting torque and centers the pump assembly, protecting pipe and wire in deep submersible installations.

Surety bond requirement

A financial assurance instrument, commonly $10,000-$25,000, kept in force while licensed so the state can fund proper well closure if the licensee defaults.

License renewal cycle

Licenses are typically renewed every 2 years, and continuing education hours must be completed before the deadline or the license lapses.

Responsible managing employee

The licensed individual designated by a contracting business who exercises direct supervision over well construction work and whose departure must be reported to the state.

Non-transferable license

A license belongs to the named individual or business entity and cannot be sold or assigned; a change of ownership requires a new license application.

Record retention

Well logs, grout records, and pump installation records must be kept for the period set by rule, commonly 3-5 years, and produced on request during inspection.

Unlicensed practice

Constructing or installing wells without a valid license is a violation, and both the individual worker and the contracting business may be penalized separately.

CE hour credit

One continuing education hour is credited per contact hour of approved instruction; a 2-year cycle commonly requires 16-24 hours with a minimum in construction topics.

CE carryover limit

Excess continuing education hours from one renewal cycle may be carried forward only up to a set cap, typically 50 percent of the next cycle requirement.

CE certificate contents

Completion certificates must show licensee name, course title, date, hours, and provider approval number, and must be retained for audit by the licensing agency.

Contamination notification

A licensee who discovers contamination or a failed well must notify the state and affected water user within the required time, commonly 24-48 hours.

Shock chlorination

The well is dosed to 100-200 ppm chlorine, held 12-24 hours, then flushed until residual falls below the potable limit before a bacteriological sample is taken.

Bacteriological sampling

Samples are collected in sterile bottles after disinfection and flushing and submitted to a certified lab; a repeat-positive result requires further corrective action.

Well abandonment

The full well bore is filled with approved grout or sealing material and capped, and the abandonment record is filed with the state to close the permit.