1	DEFINITIONS DRAWDOWN = useable tank volume The amount of water that is stored in the tank between the pump cut-in and cut-out pressures
2	DEFINITIONS PRECHARGE PRESSURE The gas pressure that is placed in the bladder tank at the factory. Precharge pressure should be 2 psi below the pump cut-in pressure.
3	DEFINITIONS PUMP CUT-IN PRESSURE - The pressure when the pump starts. PUMP CUT-OUT PRESSURE - The pressure when the pump shuts off.
4	DEFINITIONS PUMP CAPACITY The flow in gallons per minute(GPM) at a given pressure on the pump curve.
5	How a Well-X-trol^® Works Prior to the pump starting, the precharge pressure in the Well-X-trol is checked. The precharge is 2 psig below the pump cut-in pressure.
6	How a Well-X-trol^® Works When the pump is on and the pressure exceeds the precharge pressure, the diaphragm will flex in an upward position, compressing the Well-X-trol air and accepting the water.
7	How a Well-X-trol^® Works When the pump cut-out pressure is reached, the pump shuts off. The water stored in the Well-X-trol is under pressure and ready to be delivered to the system on demand.
8	How a Well-X-trol^® Works When there is a demand and the pump is not running, water under pressure will exit the Well-X-trol until the pump cut-in pressure is reached. The pump will then start.
9	Sizing the Well-X-trol^® What You Need to Know Pump capacity in GPM Minimum pump running time Pump cut-in pressure Pump cut-out pressure
10	Sizing the Well-X-trol^® (1)Determine pump capacity by using the 7 minute peak demand and number of fixtures ____ GPM (2)Determine the minimum pump running time in min. Up to and including ¾ hp………....1 minute 1 to 2 hp…………………………..2 minutes Greater than 2 hp…………………3 minutes ____ minutes
11	Sizing the Well-X-trol^® (3)Determine the minimum system operating pressure (P1) at the Well-X-trol location in psi. This is the pump cut-in pressure. ____ psi (4)Determine the maximum system operating pressure (P2) (20 psi above the pump cut-in pressure) at the Well-X-trol location in psi. This is the pump cut-out pressure. ____ psi
12	Sizing the Well-X-trol^® (5) Determine the Well-X-trol drawdown by multiplying (1) X (2)……………… ____ gallons (6) Determine acceptance factor using the pressures in (3) and (4) and either the chart or the equation: AF = 1 – ( P1+14.7) ∕ (P2+14.7) AF = ____
13	Sizing the Well-X-trol^® (7) Determine Well-X-trol Volume by dividing (5) by (6) ____ gallons (8) Select Well-X-trol model from the table. Model _______ precharged to ____ psi
14	Well-X-trol^® Sizing Example The following example will demonstrate the use of the eight steps in determining the size and model Well-X-trol. Example: A 2½ bath home that requires a minimum system pressure of 30 psi at the Well-x-trol. The well is capable of handling the system capacity demand.
15	Well-X-trol^® Sizing Example (1) Determine the pump capacity Using the Table for the 7 Minute Peak Demand, select the pump capacity required. From the Table, the flow is 14 gpm (2) Determine the minimum pump running time Assuming a 1 hp pump, the minimum running time is 2 minutes
16	Seven Minute Peak Demand Period Usage
17	Well-X-trol^® Sizing Example (3) Determine the minimum system pressure (P1) at the Well-X-trol This was given in the example as 30 psi (4) Determine the pump cut-out pressure (P2) This was given in the example as 50 psi (5) Determine the Well-X-trol drawdown Multiply Step 1 (14) X Step 2 (2) = 28 gals.
18	Acceptance Factors
19	Well-X-trol^® Sizing Example (6)Determine the acceptance factor Using the Acceptance Factor table select the acceptance factor by selecting the pump cut in pressure of 30 psi and vertically following it down until it crosses the horizontal line of the 50 psi pump cut-out pressure .31
20	Well-X-trol^® Sizing Example (7) Determine the Well-X-trol volume The volume is obtained by dividing the drawdown in step 5 (28 gals) by the acceptance factor (.31) determined from step 6 28 gals /.31 = 90 gallons
21	Well-X-trol^® Sizing Example (8) Determine the Well-X-trol model Using the Well-X-trol Selection Table, pick a model that has both the total tank volume and maximum acceptance equal to or greater than the calculated value WX-302 precharged to 28 psig
22	Well-X-trol^® Tank Selection
23	How I Size a Tank What You Need to Know Pump capacity in GPM Minimum pump running time Pump cut-in pressure Pump cut-out pressure
24	How I Size a Tank Sizing Procedure Steps Determine pump capacity (gpm) from pump info Run time based on HP 1-2 hp ---------- 2 minutes ¾ or less hp --- 1 minute (gpm rating) × (run time) = drawdown (¾ hp 10 gpm) × (1 minute run time) = 10 gal drawdown
25	I Use a Chart
26	Installation Notes The Well-x-trol’s precharge gas pressure is to be checked prior to introducing water to the system. The Well-X-trol precharge gas pressure is to be 2 psi below the pump cut-in pressure The pressure switch is to be located near the Well-X-trol
27	Installation Notes A pressure relief valve is to be installed in the system with a relief pressure equal to or less than the Well-X-trol design pressure. The flow capacity must be equal to or greater than the pump capacity at the relief pressure setting The Well-X-trol is to be installed in line before a water softener or other treatment
28	Common Well Complaints Grit and rock flour Sulfate reducing bacteria (SRB) Iron related bacteria (IRB)
29	"John Nykamp" John Nykamp, R.S. Environmental Health Program Specialist Guilford County Public Health Department 400 W. Market St Greensboro, N.C. 27401 (336)641-4807 (336)641-7613 FAX (336)641-3730 jnykamp@co.guilford.nc.us Well Contractor Certification Commissioner http://www.ncwelldriller.org/