I am about to switch to a variable speed pump to replace the single speed I have now,just looking for some opinions on which brand folks have had the best endurance and performance with.Also maybe if someone could briefly explain the relationship between pump rpm and feet of head on the pump,Ive been trying to figure how to calculate how one affects the other,but no luck yet.
variable speed pump
- Thread starter tidefanjam
- Start date
Re: variable speed ump
Take a look at the Affinity Laws on Wikipedia. http://en.wikipedia.org/wiki/Affinity_laws. Basically if you double the pump RPM, the head will go up by a factor of 4. Hope this helps.
Take a look at the Affinity Laws on Wikipedia. http://en.wikipedia.org/wiki/Affinity_laws. Basically if you double the pump RPM, the head will go up by a factor of 4. Hope this helps.
Re: variable speed ump
Both Pentair IntelliFlo and Hayward EcoStar have been around a while and gotten fairly good (though not perfect) reports.
What is it that you are actually trying to figure out? Figuring out feet of dynamic head is almost always the most difficult route for getting anywhere,
Both Pentair IntelliFlo and Hayward EcoStar have been around a while and gotten fairly good (though not perfect) reports.
What is it that you are actually trying to figure out? Figuring out feet of dynamic head is almost always the most difficult route for getting anywhere,
I was just trying to figure out how many gpm I would be able to get at the lower speeds.I took a vacuum reading from the suction side and used that and the pressure reading to come up with 40 feet of head right now.
To back up a little, why do you feel the need for a VS pump? Do you have high electrical costs? Do you have a lot of different flow rate requirements? Do you get rebates on the VS pump?
If the answer to these is NO, then you could likely same money upfront by just getting a 2-speed motor or pump and it will get you most of the electrical savings that the VS offers.
If the answer to these is NO, then you could likely same money upfront by just getting a 2-speed motor or pump and it will get you most of the electrical savings that the VS offers.
BTW, calculating the head loss and the flow rate is generally not needed for anything (and not very easy to do anyway). There is no real turn over requirement if that is what you are concerned about. Maybe this will answer some questions: pool-school/pump_run_time
If the flow with your existing pump was good, then look at a similar sized 2-speed. Realize the pumps with the same HP can in fact have very different performance curves.
If the flow with your existing pump was good, then look at a similar sized 2-speed. Realize the pumps with the same HP can in fact have very different performance curves.