Limited Specialty (D-Series) (C-61) · Lesson 4 of 6

D-35 Pool Pumps: Filtration Flow Limit, System Head and Piping Rules

"D-35 Pool Pumps: Filtration Flow Limit, System Head and Piping Rules" is lesson 4 of 6 in the Limited Specialty (D-Series) (C-61) Learning Hub. It opens with "What D-35 Installs and Where the Number Rules Are" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. What D-35 Installs and Where the Number Rules Are
  2. Listed Pumps and the Filtration Flow Limit - 150.0(p)1A and 1C
  3. The System Head Equation - 150.0(p)1B
  4. Piping Rules - 150.0(p)2
  5. Filters and Valves - 150.0(p)3 and 4

The worked example in the course applies this lesson to a realistic job in 6 steps, starting with "System head at that flow".

What you'll be able to do

  • Explain the main idea of "D-35 Pool Pumps: Filtration Flow Limit, System Head and Piping Rules" in plain language you can use on the exam.
  • Apply this step with confidence: "The System Head Equation - 150.0(p)1B".
  • Apply this step with confidence: "Piping Rules - 150.0(p)2".
  • Apply this step with confidence: "Filters and Valves - 150.0(p)3 and 4".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
D-35 POOL PUMP REPLACEMENT CHECK15,000 gallon single-family pool, 2.5 in piping, 60 gpm waterfallSINGLE-FAMILY POOL EQUIPMENT RUNPOOL15,000 gal4 diameters straight10 in for 2.5 in pipePFreturn: 8 fps maxsuction6 fps maxBackwash valve: 2 in min, orreturn pipe size if largerElbows: sweep, or drop under 30 diametersPump and replacement motor: listedCHECK THE REPLACEMENT (150.0(p))1) Turnover: 15,000 / (6 x 60) = 41.67 gpm, over the 36 gpm floor Max filtration flow 41.7 gpm2) 15,000 gal is under 17,000: C = 0.01673) H = C x F² = 0.0167 x 1,736 H = 29.0 ft of water4) Straight run: 4 x 2.5 in = 10 in5) 60 gpm waterfall, 2.5 in pipe: v = 0.4085 x 60 / 6.25 = 3.9 fps Passes 6 fps suction, 8 fps return (2 in pipe = 6.1 fps: fails suction)6) Backwash valve 2.5 in; NSF/ANSI 50 filterRESULT: 41.7 gpm max, 29.0 ft head, 10 in straight runSource: 2025 California Energy Code 150.0(p)1-4 (refers to 110.4); CSLB Get Licensed to Build, D-35.CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: What D-35 Installs and Where the Number Rules Are

CSLB defines D-35 Pool and Spa Maintenance as installing, replacing or repairing pool motors, pumps, filters, gas heaters and above-ground piping in connection with pools, including electrical switches, breakers and pool lights (CSLB, Get Licensed to Build, D-35). When you replace a pump or motor on a single-family pool, the 2025 California Energy Code Section 150.0(p) Pool Systems and Equipment Installation applies. It says the pool system must comply with the applicable requirements of Section 110.4 plus the items it lists: pump sizing and flow rate, system piping, filters and valves. This lesson uses those printed numbers; it does not cover pool structure, barriers or heaters, which belong to the C-53 trade.

Step 2: Listed Pumps and the Filtration Flow Limit - 150.0(p)1A and 1C

Dedicated-purpose pool pumps and replacement dedicated-purpose pump motors subject to State or federal appliance standards must be listed in the Energy Commission directory of certified equipment, and must meet 20 CCR Section 1605.1(g)(7) (pumps) or Section 1605.3 (replacement motors). The filtration pump must be sized, or if programmable programmed, so the filtration flow rate is not greater than the rate needed to turn over the pool water volume in 6 hours or 36 gpm, whichever is greater. So the limit is the larger of (gallons / 360 minutes) and 36 gpm.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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