Pitless adaptors are mechanical devices used to provide frost free,
sanitary well connections. They are designed to replace pump houses,
which are expensive, and well pits, which are no longer legal in
Alberta. Well pits can contaminate wells by allowing water from high
water tables, surface flooding, or broken water lines to enter a well.
Well pits can also be death traps for animals and people. Well pits can
trap explosive gasses, such as methane, and explode, or asphyxiants,
such as nitrogen or carbon dioxide and. (see Figure 1).
Figure 1. Well pit.
Pitless adaptors are commonly used for submersible pumps, where the
pressure tank is located in a basement, pump house or shop. They can
also be used for shallow and deep well jet pumps and working-head pumps.
Two common pitless adaptors are the spring-type and slotted-type (see
Figure 2).
Figure 2. Pitless adaptor types.
Installation
Pitless adaptors are installed 2 to 3 m (6 - 10 ft) below ground level
for protection from frost. The ground is excavated around the well
casing to this depth, and a hole is made in the well casing. The
discharge fitting is installed and attached to the water pipe. The
discharge fitting is either clamped, bolted or welded onto the casing.
Some pitless adaptors come as a 2 to 3 m (6 - 10 ft) pre-assembled unit.
These adaptors are attached to the well casing that has been cut off
below frost level.
Once the discharge fitting is installed and the water pipe to the
pressure tnak is in place, the excavation is backfilled with clay
material, then compacted. The well casing should extend a minimum of 20
cm (8 in) above the ground surface. A ventilated cap is installed for
sanitary protection. The ground surface around the well should be
mounded and sloped to drain water away from it.
Removal
Pitless adaptors provide convenient access to the submersible pump for
maintenance or repair. Removal of the submersible pump depends on the
type of pitless adaptor installed. Generally, a metal cable on
spring-type adaptors can be pulled to disengage the spring locking
mechanism, and the pump is pulled out using the galvanized extension
pipe. Slotted-type adaptors can be pulled directly using the galvanized
extension pipe, while some models require loosening of the adaptor
assembly with a screwdriver or wrench before pulling out the pump.
For further information, contact any of the Agricultural Water
Specialists with Alberta Agriculture and Food at the following
locations:
Lethbridge (403) 381-5846
Red Deer (403) 340-5324
Edmonton (780) 422-5000
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex1135