The color is purely cosmetic, it is exactly the same pipe and you work with it in the same way. By the by, the bell end pipes are available in white as well.
Replacing 90s before the VRV will help because of the reduced pressure loss makes the pressure higher at the VRV. However, replacing the 90s after the VRV will hurt because it would reduce the head loss after the VRV and the pressure at the VRV would drop. The difference in head loss for each 90 at 45 GPM is about 0.25 feet of head. Not much to write home about unless you have a lot of 90s.linen said:Here is/was my thought...and I bet I am over thinking this (please let me know), but in this case where I am trying to get my low speed to run the panels reliably, might long sweeps verses short ones be the difference. As we discuss this it becomes even more apparent in my thick head that I should put all six panels in parallel to also reduce loss.
Normally, I would recommend placing the VRV at the top of the panels because it make priming and draining a bit more efficient but it isn't necessary either. Some solar installers will place the VRV on the supply pipe right above the pad to make replacement easier. This also has the effect of reducing the amount of pressure the pump needs to produce to keep the VRV close. So it may possible to run on low speed even with the VRV. To make sure it is possible, what is the filter pressure with and without solar on high and low speed? Also, I can tell you what changing the 90s will do if you tell me how many 90s we are talking about and where they would be (pre vs post VRV on the supply pipe above the pad).linen said:I know I am confused about this. I had been thinking of the vacuum release being at the very top of the system, and thought it might leak if it did not have enough pressure on the water side.
Unfortunately, I did not write down my different pressures last season, and my memory is probably not too reliable. I have not opened the pool yet, so when I do this weekend (I hope to open this weekend) I can get the no solar panel readings. I will not be able to get the pressure readings with solar panels reading since they need to be installed/reinstalled perferably in their final configuration. Any thoughts at how to best proceed?mas985 said:To make sure it is possible, what is the filter pressure with and without solar on high and low speed?
I am willing to put the VRV wherever makes the most sense. Here it goes from memory (I am at work still).mas985 said:Also, I can tell you what changing the 90s will do if you tell me how many 90s we are talking about and where they would be (pre vs post VRV on the supply pipe above the pad).
Not as good a memory as I thought. The picture below shows my valving for the solar. When I took it, I realized that there are two long 90's coming from the panels that I missed in my list. The pipe coming from the filter is the flexible pvc (so that would be number two on my first list) and the pipe coming back from my solar should be at number 6 in my second list (10' feet total, with 6 feet above the valves, 4 feet below). Also, there is another 1' foot elevation I forgot from the multiport up to where the flexible pvc attaches to those valves. If it would be helpful, I can recreate the lists with these new additions.mas985 said:Wow! All from memory. I usually have to guess at most of that stuff when doing this.
Anyway, I didn't see any tees or 3-way valves. Are you running solar all the time or do you have a way to bypass it?
If you can bypass solar, where is the cut-in/out in the above list of fittings?
Also, what size eyeball is in the return?
I want to see how close I can get to actual pressure.
Yes it would and could you add the runs from the pool to the pad?If it would be helpful, I can recreate the lists with these new additions.
Will do! May take me a little time today. I appreciate your help!mas985 said:Yes it would and could you add the runs from the pool to the pad?
Thanks Mark!mas985 said:First I modeled the system without solar so once you have an actual pressure measurement with and without solar, I can recalibrate the model. For my first cut, I get about 17.5 PSI at the filter and around 43 GPM @ 49' of head.
Absolutelylinen said:43 gpm is not as bad as I thought it might be, though I would assume that goes down a bit when we get the solar in the flow?
Yes, approximately 1/2 the flow rate. If you had any check valves, it can be a little less than half depending the type of check valve. Speaking of which, if/when you add the VRV, you will probably need to add a check valve as well so the panels don't drain through the filter.linen said:Does that translate into 22.5 gpm on low, or would it be slightly higher due to the reduction in pressure loss due to lower flow rates?
No, this is based upon only the plumbing description.linen said:Did you use the filter pressure I gave you previously for this simulation/estimation?
Absolutely. You can also take the measurements with your current solar setup. Measuring both pressure and suction is probably the most accurate method of determining flow rate and plumbing head loss. A stand automobile vacuum gauge will work well or even one you get on ebay is good enough.linen said:Would getting actual accurate pressures (both filter pressure and supply side vacuum) without the solar installed help with how to install the panels?
It is basically a spreadsheet that I put together that calculates the operating point from the head loss in the plumbing and the pump head curve intersection (iterative process).linen said:On another note, if I might ask, what are you using to do the simulations?
Thinking through this...our process for turning on the panels: pump is running on high and red handle valve open, open left blue handle valve (supply to panels, open right blue valve (return from panels), then slowly close the red handle valve. Continue to run on high until any air bubbles cease going to the pool, then flip the switch to low flow.mas985 said:if/when you add the VRV, you will probably need to add a check valve as well so the panels don't drain through the filter.
I can't unless I put the old piping back up on the roof.mas985 said:You can also take the measurements with your current solar setup.
I already have a vacuum gauge connected to my pump basket drain port itching to tell me how low it ismas985 said:A stand automobile vacuum gauge will work well or even one you get on ebay is good enough.
I was expecting this to be alot higher due to the 1.5" diameter.mas985 said:Suction Head Loss (ft) 1.7
How much does this improve if I go up to something like a S244T (3 sq. ft.) sand filter, or is a good portion due to the valve?mas985 said:Pad Head Loss (ft) 22.6 (backwash valve and filter are most of this)
Wow, that is alot! I would not have guessed so much of my total head loss was there. Per the VRV comment, is that assuming it is at the top of the panels, or also if it is just above the solar cutover valve?mas985 said:Jet Head Loss (ft) 19.5 (larger eyeballs would reduce this but this may actually help the VRV)
No it wouldn't be needed. You just want to make sure you don't get draining through the filter.With this procedure, would a check valve be needed since the valve would be closed?
Mostly, the VRV is for self draining but since you don't have automatic solar valve, maybe that isn't all that important. Also, there is probably little risk given your location so you could probably do without the VRV.Also, in this scenario, is the risk of not having a VRV that the panels/plumbing gets hot and over pressurizes?
Yes because they would be self draining at that point.If I have a VRV, I assume the check valve would need to be between the filter and my solar cutover/bypass valves?
That is because it is total suction head loss = dynamic + static. There is 3 feet of static head gain because the water level, I assumed, was above the pump level. Let me know if that is not the case.I was expecting this to be alot higher due to the 1.5" diameter.
I just realized I uses the wrong curve for your filter. Sometimes it takes a couple of iterations to get everything right. Here are the updated numbers with both filters (the first number is your current filter, the second number is with a filter change):How much does this improve if I go up to something like a S244T (3 sq. ft.) sand filter, or is a good portion due to the valve?
A single eyeball going from 1.5" down to 3/4" can have a lot of head loss but that is what I consider good head loss because that energy is converted to exit velocity. But as for the VRV, if placed on the supply side a few feet above the filter/water line, the extra pressure caused by the eyeball can help keep the VRV closed on low speed.Wow, that is alot! I would not have guessed so much of my total head loss was there. Per the VRV comment, is that assuming it is at the top of the panels, or also if it is just above the solar cutover valve?
Good to know.mas985 said:Mostly, the VRV is for self draining but since you don't have automatic solar valve, maybe that isn't all that important. Also, there is probably little risk given your location so you could probably do without the VRV.
That is a good idea. I am not familiar with pool VRVs, I have used Oatley air admitance valves in dwv applications, are the VRVs similar? Is something like this appropriate: http://www.homedepot.com/buy/plumbi...rim-kit-only-handles-not-included-167123.htmlmas985 said:One thing you could do is plumb in a tee for a threaded VRV and just plug it for now or even put a valve on it for manual venting and draining. That way if you decide you want self draining panels, you can easily add the VRV. It just needs to be a few feet above the pool level and filter.
Yes, that is about right. I forgot about the pool head height.mas985 said:That is because it is total suction head loss = dynamic + static. There is 3 feet of static head gain because the water level, I assumed, was above the pump level. Let me know if that is not the case.
That may have been my fault, I called it a hayward meteor and I think it is a pentair 20" meteor filter...sorry about that.mas985 said:I just realized I uses the wrong curve for your filter.
That is good to know. I assume if I hooked up my backup sand filter (it is a 19' jacuzzi laser) instead of my 20" meteor, the head loss change would be minimal? Are there other multiport valves (or others valves) that have significantly lower head loss?mas985 said:There is not much of a difference due to the filter change and most of the pad head loss is in the backwash valve.
This threw me a curve, I thought I would be able to measure my vacuum, but I think my gauge does not have the resolution needed since it goes down to ~29 in Hg vacuum.mas985 said:Estimated Suction (in hg.) 1.96 2.03
Sorry it took so long for me to answer...kids baseball games. I recall 19 psi when pump was on high and filter was clean, I do not remember the low psi.mas985 said:Also, remind me what your filter pressure was when you had the old solar installed?
The optimum flow rate through a solar system is 1 to 4 gpm per panel.
For reference, the date on the literature was 04/10.An integrated disc at the mid-point within the "Inlet/Oulet" header automatically diverts the right amount of flow through the solar panel.