Surge Tank

The surge tank fundamentally supports the gutter system, which captures surface water and absorbs of waves formed within the pool. The water on the surface has the potential to be the dirtiest in the pool. Debris (such as leaves, pollen), algae spores and oils (from skin, sun screen lotion) collect on the surface. The sun's UV rays break down disinfectant (chlorine) most at the surface. It is important that this water be collected with priority.

When the flow from the gutters is not sufficient (due to water level and/or a lack of waves), additional flow from the drain is required to maintain the surge tank level. This is typically handled via a modulation valve on the drain inlet to the surge tank, controlled by a level monitoring mechanism (such as a float). When a modulation valve is not present, flow much be restricted on the drain return and the pool level must be maintained to ensure some amount of gutter return is present.

Low Water Level

When the surge tank is too low, this is typically due to one of more of the following reasons:

• The pool water level is too low (when a drain return modulating valve is not present). Fill the pool.
• The drain return modulating valve is malfunctioning, if present. Service the valve.
• The main pump flow rate is too high. Reduce the outlet flow rate (only after ensuring that other conditions are not present).

When a drain return modulating valve is not present, it is important that the drain return is restricted (the valve is partially closed). Otherwise, flow from the drain will potentially prevent adequate flow from the gutter return. In an ideal case, the surge tank should always have a modulating valve on the drain return.

High Water Level

Typically, high water in the surge tank is not of concern (unless it has nearly reached or exceeded the overflow point, of course). High water is usually the result of:

• A nominal or slightly elevated pool water level in conjunction with a large amount of pool activity (spilling water into the gutters).
• Limited flow into the filter system due to a plugged strainer basket or blockage elsewhere.
• Excess water in the pool due to over-filling or a significant rain event (in this case, some water may be removed via backwash at the operator's discretion).

All three scenarios, of course, assume the main pump is operating. The surge tank will rise to a relatively high level shortly after the main pump is disabled (it will match the pool level).

Future Overhaul

To fully address the known deficiencies, an overhaul of the surge tank is planned as the budget permits.

Modulating Drain Valve

Motorized Actuator

A Bray 70-0201H motorized valve has been selected for the application. This is a Bray Series 70 Actuator, with a 2,000 in-lb turning capacity, configured for 120 VAC on/off operation. A heater and auxiliary contacts are included.

The part number breakdown is approximately as follows (some interpretation):

Part Number		Description	Comment
Series	70	Series 70 (On/Off)
Supply	(blank)	120 VAC
Torque	0201	2,000 lb-in torque
Heater	H	Heater is included

This particular model has:

• A single-phase reversible permanent split capacitor induction motor.
• 2 x SPDT 10 A auxiliary switches.
• 2 x 3/4" NPT conduit entries.
• A 5 W PTC style heater (to drive out condensation).
• 30 second stroke time (at 60 Hz).

Other notes:

• The motor has an internal thermal trip set at 135 °C.
• Terminals are sized for #22 AWG to #14 AWG.

Valve

The recommended valve is a Bray 300800-11010119. An exact breakdown of the part number cannot be located, but it appears that it means the following:

Part Number		Description	Comment
Series	30	Series 30 (wafer)
Size	0800	8 inch
Base Part	11010	TBD	Unable to locate specifics.
Material Code	119	Body: Cast Iron Disc: Nylon Coated Ductile Iron Stem: 416 Stainless Steel Seat: EDPM

• Bray Series 30 wafer butterfly
• 8-inch (200 mm)
• Cast iron body, 416 stainless steel stem

S70 NEMA 4X 2,000 lb-in 24 VAC/DC

4-20 mA Aux Switches Heater Battery Backup

$3084.40

Bray 70-0201SVH