- Jul 8, 2011
- 41
mas985 said:Ok now that you have the pump figured out, there is another issue.
With a pump that large I would have expected a lot more head loss on 2"/1.5" plumbing. 48' of head loss is very low for 1.5" plumbing and would put the flow rate at 90 GPM. Is there only a single 1 1/2" return line from pool to pad or are there actually 4 separate return lines that split at the pad, one to each eyeball?
That sounds pretty close, but to make matters more confusing, the pump I'm using for these readings is an unknown spare pump. This one is marked Challenger Centurian and has 2 capacitors, while my original pump has only one capacitor. When I started my pool a month ago I discovered that the original pump has trashed bearings, which led me to decide to get a two-speed pump now. The spare pump (now in use) has no model number anywhere and I never looked at it's impeller to see it's size.DaveAZ said:My existing equipment has a 1HP impeller and the side of the housing front is marked 1HP. For the purposes of their curve, 1HP applies, not 3/4 HP . Shouldn't that be 84 GPM @ 46' of head?
The discharge side plumbing has a single 1-1/2" line from the backflow valve to below ground. I doubt the builders would have gone to the expense in extra pipe and labor to manifold them underground, and the nearest eyeball absolutely gets a lot more flow than the farthest. At most, they may have an underground Tee fitting and have gone in both directions around the pool.
All the gauges are new and seem to be fine. I have no idea of their accuracy.mas985 said:Also, the other thing that doesn't make sense is that when you have the KK fully engaged, you have less head loss than when you have two suction ports, 37' of head vs 48' with both suction ports open. That is impossible so one or more of the measurements must be incorrect. Because of the excess head loss on the suction side, this makes the pressure readings very low so I suspect there is a lot of error in the pressure reading. Are you confident that both gauges are operating correctly?
mas985 said:At this point, I can't tell you what is going on since nothing seems to make sense.
Ok, just I went out and took a new set of consecutive readings with the diverter valve in different positions. The filter is no longer clean, so these will not be the best to establish a TDH for selection puposes. My pool is still dirty from the huge dust storm (Haboob) that passed through last week and the filter gets full in only a few days of running. I'd be willing to do this again with a clean filter if the results would get me an answer to the question of "Will the KK work on low speed and still have a little left over flow for the skimmer?" (I'm not sure what we are looking for in these calcs.)
1. Skimmer closed: 1 to 2 PSI / -22 in. Wg.= 32.48 ft.H2O
2. KK closed: 16 PSI / -7 in. Wg.= 47.87 ft.H2O
3. Diverter not obstructing: 16 PSI / -5 in. Wg. (Vacuum needle bouncing a lot) 45.61 ft.H2O
4. Diverter partially obstructing skimmer. 10 PSI / -17 In. Wg. = 45.31 ft. H2O
5. Diverter partially obstructing skimmer. 12 PSI / -15 In. Wg. = 47.67 ft.H2O
6. Diverter partially obstructing skimmer. 14 PSI / -12 to -13 In. Wg. =50.03 ft.H2O
7. Diverter partially obstructing skimmer. 16 PSI / -9 In. Wg = 50.13 ft.H2O
My very first readings, done with a clean filter and the diverter in my usual running position, which I based my original calculation on: 14 PSI / 9 In. Wg = 45.51 ft.H2O
Definitely not. My pool budget is steering me towards a remanufactured 2 speed pump. My family uses my pool a handful of times a year, mostly when guests are here.mas985 said:Have you thought about a VS pump? In situations such as this, it takes the guess work out of things. Of course it costs a lot more too.
I'm under the impression that my pool plumbing can get by with the smallest 220V 3/4 HP 2-speed that I can find. I can start out running it with the 1HP impeller and see what results it gives me. I doubt I'd need to switch to a 3/4 HP impeller for any reason.
I'm thinking my motor selection choices would be any of the following, based on rebuilt availability or least price new:
B2980
B862SE
B980
SQS1072R (48Y)
UQS1102R (48Y, 1HP, up-rated)
I'd like to compare them, but no curves are available for specific motors.