NABCEP SHI cheat sheet

OSHA construction fall protection is required at 6 ft (1.8 m) above a lower level; roof edges, skylights, and open penetrations need guardrails, covers, or personal fall arrest.

A roof-access ladder must extend 3 ft (0.9 m) above the landing and be secured; maintain three-point contact and a 1:4 ladder angle.

PV source circuits remain energized whenever exposed to light; treat DC conductors as live, use a CAT III meter, and verify zero voltage after isolation.

Stored solar hot water can stratify above 160°F (71°C); isolate and drain before opening, and use a tempering valve to limit domestic delivery to about 120°F (49°C).

Glycol and pool chemicals require SDS access, chemical goggles, gloves, and ventilation; chlorine products must not contact acid or ammonia.

Collectors commonly weigh 80–150 lb (36–68 kg); use two-person lifts or a hoist and verify roof staging load limits before moving them.

Soldering and torch work require a fire watch, shielding from combustible roof materials, and a charged extinguisher within reach.

Heat illness risk rises with WBGT; use acclimatization, water, rest, and shade, and stop work for confusion, collapse, or severe cramping.

Lockout/tagout applies to line-voltage pumps, controllers, and pool equipment; isolate all sources, including dual-supply PV and grid.

In the northern hemisphere, true south is the reference azimuth; correct compass readings for magnetic declination before setting collector orientation.

Year-round domestic hot water collectors typically tilt near latitude; winter-biased designs add 10–15°, while summer pool heating may subtract 10–15°.

A solar window of about 9 a.m. to 3 p.m. year-round is the usual shading criterion; check winter solstice because shadows are longest then.

Roof structural review must compare collector dead load, rack, and fluid weight with existing dead, live, snow, and wind loads; do not assume rafter capacity.

Confirm roof covering age and remaining service life; mounting over deteriorated shingles can void warranties and create leak callbacks.

Measure pipe route length, elevation gain, and fitting count to estimate pump head; short, insulated runs reduce heat loss and pump energy.

Freeze design uses the lowest expected ambient temperature, not the average; select drainback, recirculation, or glycol protection from that value.

Water quality tests should include hardness, pH, chloride, and total dissolved solids; hard or high-chloride water affects scaling and corrosion.

Design package review checks collector SRCC rating, array area, flow rate, pipe size, pump curve, controller sensors, relief valve, and wind/snow attachments.

Collector arrays add dead load from collector, rack, fluid, and snow; calculate pounds per square foot over the tributary roof area and compare to structural capacity.

Lag screws or structural screws must engage rafters or trusses at manufacturer-specified embedment; decking alone is not a structural attachment.

Every roof penetration needs flashed and counter-flashed detailing; sealant is a secondary weather barrier, not the primary flashing.

Rail and standoff spacing must follow the rack manufacturer's span table and the project's wind uplift and snow load calculations.

Wind uplift is highest at roof corners and edges; add attachments there per ASCE 7 or local code and manufacturer engineering.

Ground-mount piers must extend below frost depth and be designed for overturning from wind; concrete must cure before loading.

Row spacing to avoid winter shading: D = H / tan(alpha), where H is collector height above the row and alpha is the minimum solar altitude at the critical time.

Isolate dissimilar metals with dielectric bushings or washers; copper-to-aluminum contact causes galvanic corrosion.

Seismic bracing and flexible connections are required where code or manufacturer dictates; rigid piping can transfer movement to collectors.

Typical flat-plate collector design flow is about 0.05 gpm per square foot (0.002 L/s per m²); verify the exact value in the collector manual.

Keep pipe velocity generally below 5 ft/s (1.5 m/s) in copper and below 4 ft/s in plastic to limit erosion, noise, and pressure drop.

Drainback piping must slope continuously to the drainback tank, typically at least 1/4 in per foot (2%), with no traps or high points.

A pressure relief valve must protect the solar loop and tank; typical settings are 150 psi (1,034 kPa) for the loop and 210°F (99°C) temperature relief.

Glycol freeze protection must cover the lowest ambient plus margin; 30–50% propylene glycol is common, and concentration above 60% reduces heat transfer.

Expansion tank precharge and size depend on system volume, maximum temperature, and glycol expansion; undersizing causes relief valve discharge.

Potable water connections need backflow prevention and a thermal expansion tank; a check valve alone does not protect the potable supply.

Use high-temperature, UV-rated insulation on solar loop piping; butt insulation tightly and protect it from roof traffic and UV.

Pool loops use a heat exchanger or direct collector loop with corrosion-resistant materials; interlock solar flow with pool filtration and add a check valve.

Differential control turn-on is typically 8–12°F (4–7°C) above tank temperature; turn-off is about 4°F (2°C) to prevent short cycling.

The collector sensor belongs at the collector hot outlet, and the tank sensor at the lower tank; both must be thermally coupled and shielded.

Freeze protection recirculation usually starts near 38–40°F (3–4°C); drainback systems instead rely on pump-off draining and slope.

High-limit control stops the pump near 180–200°F (82–93°C) or per manufacturer; stagnation must be planned, not treated as a fault.

Pump selection must use the system curve and collector manufacturer's flow rate; a valve balances flow and an isolation flange allows service.

Line-voltage solar equipment needs a disconnect, overcurrent protection, and GFCI where required; pool pumps require GFCI protection per code.

Keep low-voltage sensor wiring separate from line-voltage conductors; use shielded cable and grounded shielding where noise is present.

A PV-direct pump has no battery; its flow varies with irradiance, so commissioning must verify performance at design solar noon.

Pool solar controls should run only when the filter pump is on and freeze protection is active; a flow switch or pressure switch confirms flow.

Pressure-test the solar loop at 1.5 times the maximum operating pressure or per code, hold the test, and record the result before insulation.

Commissioning records should include cold fill pressure, pump current, flow rate, collector and tank temperatures, delta-T, and glycol concentration.

Purge air from the loop at the highest point and verify the air eliminator; air locks cause high outlet temperature and low flow.

A no-heat complaint is checked in order: pump operation, controller sensor readings, flow, air lock, freeze protection, and collector isolation valves.

Glycol should be tested annually for pH and inhibitor; many propylene glycol systems need replacement every 3–5 years or per test results.

Maintenance includes collector cleaning, relief valve exercise, insulation inspection, sensor calibration, and pump/check valve checks.

Handover must include manuals, warranties, freeze protection instructions, controller settings, shutoff locations, and emergency procedures.

Scald protection at the point of use is verified at handover; a tempering valve should limit hot water delivery to about 120°F (49°C).

Pool system handover covers filter operation, solar bypass valves, freeze protection, and the expected temperature rise per day.