Irrigation System Installation & Maintenance Flashcards

A customer asks the technician to add three new sprinkler heads to an existing zone. Before doing so, the technician should first verify that:

Answer: The zone's existing flow capacity (GPM) and pipe sizing can support the additional heads without exceeding the water supply's capacity or causing excessive velocity

Adding heads increases the zone's flow demand. The technician must verify that the water supply can handle the additional GPM, that the pipe is sized for the increased flow (velocity below 5 fps), and that pressure will remain adequate at all heads including the new ones.

When flushing an irrigation mainline after a repair, the purpose is to:

Answer: Remove debris (pipe shavings, dirt, solvent cement residue) that entered the pipe during the repair, preventing it from clogging valves, nozzles, and emitters

After any pipe work, debris from cutting, digging, and cementing can enter the pipe. Flushing the mainline with water before reconnecting downstream components removes this debris, preventing it from clogging zone valves, sprinkler nozzles, and drip emitters.

A mid-season irrigation audit reveals that the system's distribution uniformity (DU) has dropped from 70% to 50%. What is the most likely cause?

Answer: Clogged nozzles, tilted heads, sunken heads, or worn nozzles causing uneven water distribution

A significant drop in DU during the season is typically caused by physical changes to the sprinkler heads: nozzle clogging, heads knocked out of alignment by mowers, heads sinking below grade, or nozzles worn to irregular patterns. These issues cause some areas to receive much more or less water than designed.

Trenching in heavy clay soil requires special consideration because:

Answer: Clay soil tends to smear and seal the trench walls, which can direct water along the trench line (creating a 'French drain' effect) and slow backfill compaction

Clay soil presents unique installation challenges: the smooth trench walls can channel water along the pipe (creating subsurface drainage paths), clay clumps are difficult to compact as backfill, and clay expands and contracts with moisture changes, potentially shifting pipes and heads.

What is the recommended method for locating an irrigation wire break that is causing a zone to stop working?

Answer: Use a systematic approach: test resistance at the controller, then use a wire locator/tracer to follow the wire path and identify the exact break location

A systematic diagnostic approach starts with resistance testing at the controller (infinite resistance confirms a break vs. a short), then uses a wire and valve locator to trace the wire path and pinpoint the break location — where the signal stops — allowing a targeted repair.

When installing irrigation components near a swimming pool, what minimum setback distance is typically required for sprinkler heads?

Answer: Sprinkler spray should not reach the pool deck or pool water — typically 5-10 feet depending on local code, and drip or subsurface irrigation is preferred near pools

Sprinkler heads must be positioned so their spray does not reach the pool deck (slip hazard) or pool water (introduces fertilizer, debris, and pathogens). Most codes require 5-10 feet setback, and drip or subsurface irrigation is preferred for pool-adjacent landscaping.