There is a buzz around here that the government is either giving an incentive or requiring commercial pools have 3 speed pumps. I have not been able to nail it down yet but my first question is, has the health department rescinded the rule that the pump shall run at the rated speed 24/7? My next question is why 3 speeds?
The pool company who says it is true is clueless as to anything about it.
I have done some digging and this idea came from California. It is certainly the energy code there. The question is whether this is a federal law, an incentive rebate or just a rumor that a pool company guy embraced to make some extra money. The pump is about 2.5 times as much.
Judy is going to check with the pool (health) inspector tomorrow to see if it is even legal on a commercial pool. That would be my first concern because that guy can throw a red tag and shut you down. You certainly would not want to be several hundred dollars into this and find out you still have run your pump at high speed all night anyway. If they can find a compromise I can see how this would save a boat load of money. These pools are only licensed to operate during daylight hours.
I have done some digging and this idea came from California. It is certainly the energy code there.
I checked through the current versions of CEC Title 24, Part 6 (California Energy Code) for reference data per the above quote. The requirement is only for Residential Installations, and the Motor is to be minimum of Two Speeds (Details are pasted below).
The Regulation(s) are located within Chapter 5 (Mechanical) of the 2008 "Residential Compliance Manual", along with the "Appliance Efficiency Standards".
Below are snips from 2008 CEC T24 Part 6...
Text From 2008 CEC Title 24, Part 6 Appliance Standards:
(5) Residential Pool Pumps.
(A) Motor Efficiency: Pool pump motors manufactured on or after January 1, 2006 may not be split-phase or capacitor start – induction run type.
(B) Two-Speed Capability;
(i) Pump Motors: Pool pump motors with a capacity of 1 HP or more which are manufactured on or after January 1, 2008, shall have the capability of operating at two or more speeds with a low speed having a rotation rate that is no more than one-half of the motor’s maximum rotation rate.
(ii) Pump Controls: Pool pump motor controls manufactured on or after January 1, 2008 shall have the capability of operating the pool pump at least two speeds. The default circulation speed shall be the lowest speed, with a high speed override capability being for a temporary period not to exceed one normal cycle.
Text From 2008 CEC Title 24, Part 6 Residential Compliance Standards:
Article 5.2.9 (Mechanical)
5.2.9: Pool and Spa Equipment
Pool Pump Requirements:
For maximum energy efficiency, pool filtration should be operated at the lowest possible flow rate for a time period that provides sufficient water turnover for clarity and sanitation. Auxiliary pool loads that require high flow rates such as spas, pool cleaners, and water features, should be operated separately from the filtration to allow the filtration flow rate to be kept to a minimum.
All pumps and pump motors shall comply with the specifications of the Appliance Efficiency Regulations.
The pool filtration flow rate may not be greater than the rate needed to turn over the pool water volume in 6 hours or 36 gpm, whichever is greater. This means that for pools of less than 13,000 gallons the pump must be sized to have a flow rate of less than 36 gpm and for pools of greater than 13,000 gallons, the pump must be sized using the following equation:
Max Flow Rate (gpm) = Pool Volume (gallons) / 360 min.
These are maximum flow rates. Lower flow rates and longer filtration times are encouraged and will result in added energy savings.
Pools with auxiliary pool loads must use either a multi-speed pump or a separate pump for each auxiliary pool load. For example, if a spa shares the pool filtration system, either a multi-speed pump must be used or a separate pump must be provided to operate the spa.
If the pool system can be served by one pump of less than 1 total-hp in capacity, the pump may be single speed.
Filtration pump motors with a capacity of 1 total-hp or more must be multi-speed.
All pool pumps sold in California must be tested and listed with the Energy Commission according to the Appliance Efficiency Regulations.
Pump manufacturers must list flow rate, power, and energy factor at each of three system curves (see Figure 5-3). "Note: Figure 5-3 not included with this text." S.E.T. 07292010
For pools equal to or less than 17,000 gallons, a pump must be chosen such that the flow rate listed for Curve A is less than the 6-hour turnover rate. For pools greater than 17,000 gallons, a pump must be chosen such that the listed flow rate at Curve C is less than the 6-hour turnover rate.
Pool Pump Controls: Pool controls are a critical element of energy efficient pool design. Modern pool controls allow for auxiliary loads such as cleaning systems, solar heating, and temporary water features without compromising energy savings.
§114(b) A time switch or similar control mechanism must be installed as part of the pool water circulation control system that will allow all pumps to be set or programmed to run only during the off-peak electric demand period and for the minimum time necessary to maintain the water in the condition required by applicable public health standards.
§150 (p)1 Multi-speed pumps must have controls that default to the filtration flow rate when no auxiliary pool loads are operating. The controls must also default to the filtration flow rate setting within 24 hours and must have a temporary override capability for servicing.
The requirement for filtration of commercial pools is that the water be filtered 3x within a 24 hour period.
This might be accomplished via the method described to you however the second requirement is that there be a continuous means of disinfection (auto chlorinator) and this cannot happen without the filter pump running.
End result: Filter must run 24/7.
Hope this helps.Officials name & title deleted due to lack of permission to publish.
I suppose the real answer is in what the calculated turnover is with the existing pump. I believe the design spec is every 6 hours. If that is the case you could run it 12 hours at normal speed (2 turnovers), and then run it half speed for 12 hours to get the 3d turn over. I am still not sure why they say 3 speeds.
Greg, Not sure if I should be saying this, but I'd like to play the VSD card here. Most VSD's have options to turn the motor on or off at a given time, with a simple induction motor. My question is, why complicate things why a 3-speed motor?