I think that when you start with a fully regenerated resin bed--I will use a 1 cubic foot resin bed as an example and assume that a fully regenerated bed is 30,000 grains--then if only half of the capacity is used before regeneration, (15,000 grains) and the appropriate salt dose is used to regenerate 15,000 grains (about 4 lbs) it seems that a full 30,000 grains bed is again available. I can't really explain why this seems to be what happens and in some ways it appears to be counter intuitive because I think it is well understood and accepted that if that same 1 cubic foot of resin was fully exhaused that it would take 15 lbs of salt to fully regenerate it.
If the bed does become fully depleted--for what ever reason--it is necessary to recharge the bed with the maximum salt dose--15 lbs per cubic foot. As you know Gary Slusser recommends that the maximum dose be applied twice in succession if the bed is fully depleted and in my experience that works very well in reestablishing a fully charged bed that can then be successfully recharged with low salt doses after partial exhaustion.
Last edited by Bob999; 02-08-2010 at 04:51 PM. Reason: spelling
Do we need to go back to class on all the items that can and do cause pressure drops and what drops at what pressure? Head loss at 20psi and head loss at 60 psi?
Pressure loss is a function of flow. I think this is why the specs for softener heads are for pressure loss at a specified flow--the industry standard is to list the flow at which a 15 psi pressure drop occurs. Of course you need pressure differential to get flow so there is no pressure loss from flow if there is no pressure and as the input pressure to a system is increased the potential for greater flow also increases.
So I think Gary's observation of "the higher the pressure, the higher the pressure loss of fittings, valves, tubing etc" is fully consistent--higher pressure in a given system will result in higher flows when, for example, a faucet is opened. It is also consistent with the fact that pressure drop in the system is a function of flow--the higher the flow in any given system the higher the pressure drop.
Last edited by Bob999; 02-09-2010 at 05:49 AM. Reason: add information
What we are really talking about is friction loss. PSI is a function of the pump delivering water to the system. Volume is dependent on pipe size, head pressure and friction loss. The fourmula is F=0.282 (110/c) 1.85 [(q)1.85/(d)4.8655]
where f = friction head in feet of liquid per 100' of pipe ( fittings, valves, equipment have an equivilant number assigned)
d = inside pipe diameter
q = Fluid flow in gpm
c = Surface roughness constant (from published data)
Psi loss is a function of velocity (mentioned as "flow" here). As velocity increases, friction increases (surface roughness), i.e. psi loss increases. If the static pressure to a system increases and the ID of the piping serving the system is not increased then the velocity (flow) increases and higher psi loss can result (although the resultant psi at the end of the line will still be higher after the psi losses are removed).
When pipe size is increased (larger ID) then the velocity is reduced at any given pressure, i.e. less psi loss. This is the whole reason why I'm leaning towards the 1.25" valve, larger ID, i.e. less psi loss at either normal or full bore flow at my given pressures. Plus I plan to run a 1.25" trunk line from the softener to the water heaters and then to the bathrooms.
I anticipate having ~ 65 psi at the home and would like more than 50 psi in the showers, especially considering the multiple shower head flow capability they will have.
My switch is set at 85-105 and yes I already have a 2" csv. The setting is so high due to the elevation difference between the well and the house pad (~ 30 psi loss). At flows above 5 gpm the csv is set at 95...i.e. ~ 65 psi at the home.
[QUOTE=Gary Slusser;248272]Agreed. Any idea of how much pressure loss with 65 psi through say 10" of 1" and then into 14"-16" for 65" and then into 6' of 1"?
For 1" copper with a 5 ft/sec. velocity the charts show a 10 psi drop of 10 lbs/psi @ 20 gpm for 100' of pipe so.. that works out to 1/10lb/psi for 1' of pipe.
And the figures I mentioned are very close to the distance and internal ID of a 3-4 cuft softener with regular mesh resin including a gravel underbed and a Clack WS-1 (1") control valve, including the factory bypass valve with separate (1") in/outlet ball valves.
I agree that hardness typically varies. A system should be designed for the maximum hardnes seen to achieve consistently soft water. If the system is not so designed then the customer will almost certainly deplete the resin at some point and need to do the back to back max salt dose regenerations. But I see this as applying whether there is 2 cubic foot of resin or 4 cubic foot of resin.