Surge Tank: Difference between revisions
→Structural and Surface
Matt Parnell (talk | contribs) No edit summary |
Matt Parnell (talk | contribs) |
||
| (10 intermediate revisions by the same user not shown) | |||
| Line 25: | Line 25: | ||
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. | 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 === | === High Water Level === | ||
| Line 43: | Line 39: | ||
A combination of age and inadequate repairs in the past have led to a number of known deficiencies with the surge tank. These deficiencies have both functional and (to a much lesser extent) aesthetic implications. | A combination of age and inadequate repairs in the past have led to a number of known deficiencies with the surge tank. These deficiencies have both functional and (to a much lesser extent) aesthetic implications. | ||
All issues are as identified in January 2022. These issues should be corrected as soon as possible. | |||
* There is no modulating valve on the drain return. The impact of this is described in the [[#Theory of Operation|theory of operation]]. According to the [[Pool Annual Inspection#Pool Functionality|pool annual inspection]], 80% of the total flow to the surge tank must be from the gutters. It is difficult to maintain this operating status without a modulating valve. | |||
** There was, at some point, a Fisher valve installed. A stainless steel float ball, with piping for hydraulic control, is still present in the tank. It is not known when this was removed and replaced with manual isolation valves. | |||
* The isolation valves between the pool and surge tank are failing or have failed. It appears that in [[Club History#2016]], the pool drain valve failed to the point that it could no longer be turned. In response to this, an additional butterfly valve was installed <i>inside</i> the surge tank to allow the pool to be shut down (all water from the pool must be isolated). This is very risky, as the drain isolation cannot be accessed from outside the surge tank. Watching a service person open or close this valve is an "interesting" event. | |||
* The surge tank drain-to-sump valve has nearly failed. During the pool closing in 2021, the service person had a very difficult time opening this valve. If it breaks, the pool cannot be opened. | |||
* The exit pipe is oddly routed, likely in response to a cheap fix when piping was replaced. The exit pipe should be straight, eliminating a multitude of 90's between the surge tank and the strainer basket. | |||
* The tank leaks at several penetration points. Rudimentary fixes with hydraulic cement have been attempted, but many are failing. | |||
* Multiple old penetrations exist, providing potential leak points. This is also an aesthetic issue. | |||
* The inside surface of the tank has deteriorated and must be stripped and coated for longevity. | |||
* There is no overflow pipe. It was capped-over at some point. This is a minor code issue. | |||
=== Workarounds === | |||
* To address the lack of modulating valve, the drain return valve is set to be only partially opened. By doing so, only a portion of the pump demand is met by the drain return. The rest must be supplied by the gutter return. This works to an extent, but: | |||
** If the pool water level is too low, insufficient gutter flow can lead to a critically low level in the surge tank. At this point, the automation system will shut down the main pump for safety. This is typically mitigated by engaging the auto-fill (which also feeds into the surge tank). | |||
** When the pool is very active, there is no way to reduce drain return flow to increase gutter return flow. Hence, the gutters are prone to overflow during busy periods. | |||
* Some additional patching has been applied to seal leaks, but it has shown to be ineffective. As of 2021, small but persistent leaks were observed. | |||
== Future Overhaul == | == Future Overhaul == | ||
To fully address the [[#Known Deficiencies|known deficiencies]], an overhaul of the surge tank is planned as the budget permits. | To fully address the [[#Known Deficiencies|known deficiencies]], an overhaul of the surge tank is planned as the budget permits. | ||
=== Isolation Valves === | |||
There are three isolation valves to be replaced. Details to follow. | |||
=== Maintenance Drain Valves === | |||
There are three maintenance drain valves - not to be confused with the pool drain return valve(s). Details to follow. | |||
=== Modulating Drain Valve === | === Modulating Drain Valve === | ||
The modulating valve utilizes a motorized actuator to turn a butterfly valve on the drain return. The term "modulating" implies that the valve can be fully open, fully closed, or operating at a point in-between. | |||
==== Motorized Actuator ==== | ==== Motorized Actuator ==== | ||
| Line 94: | Line 119: | ||
* The motor has an internal thermal trip set at 135 °C. | * The motor has an internal thermal trip set at 135 °C. | ||
* Terminals are sized for #22 AWG to #14 AWG. | * Terminals are sized for #22 AWG to #14 AWG. | ||
This actuator has been purchased as of January 2022 and is awaiting installation. | |||
Previously, a Bray 70-24-0201SVH-BBU was recommended. However, 24V operation, the internal 4-20 mA controller, and the battery backup unit (BBU) all add unnecessary cost. | |||
==== Valve ==== | ==== Valve ==== | ||
| Line 128: | Line 157: | ||
|} | |} | ||
This actuator has been purchased as of January 2022 and is awaiting installation. | |||
=== Piping === | |||
Details to follow. | |||
=== Structural and Surface === | |||
Details to follow. | |||