I just bought a house with a pool in August last year. We enjoyed it for another month or so before closing. I'm trying to open the pool this week and having issues with the skimmer vac.
It's an in-ground vinyl pool about 20x40 lazy L with a 6ft deep end a 3 ft shallow. It's probably about 26,000 ga. It uses a Hayward D.E. filter and Hayward 1.5hp pump (don't know the age of either). When I bought the house, I had a pool inspector out (he only inspects and doesn't service or sell stuff, so I know he's a neutral party), he said the equipment looked good and was properly sized.
I have a deep end and shallow end skimmers and two main drains. These 3 branches plumb back to a "manifold" that has a separate ball valve for each (i.e. 3 valves - 1 for deep end skimmer, 1 for shallow skimmer, 1 for the main drains), after the valves, they junction to one line that goes to the pump basket. After the filter, the return line gets tee'd off into 3 branches (I call this a manifold) with 3 ball valves. One branch goes to the deep end return jets (there are two jets on the wall), one branch goes to the shallow end jets in the stairs (there are two jets here as well) and one branch goes to a port that is plugged on the long side wall midway in the deep end (I assume for a water powered robot vacuum?).
When I took ownership of the house, I tried using the skimmer vacuum to clean the pool, it never worked quite right (it never really had good suction). I would put the vac hose into the pool until water came out the skimmer end of the vac hose and then put the skim-vac attachment onto the skimmer and try vacuuming. I didn't bother to trouble shoot because I had an electric robot vacuum on the way. I also noticed that when I wasn't vacuuming and everything was running on normal mode, the shallow end skimmer usually didn't have very good suction (it didn't pull a lot of stuff into the basket like the deep end skimmer did). I also noticed that when I took the skimmer gizmo out after opening the pool, there was a really strong chlorine smell from the shallow skimmer. I didn't notice so strong of a smell from the deep end skimmer when removing the gizmo.
Anyway, I went to open the pool the other day and put the filter valve on waste, kept the main drain closed, the shallow skimmer closed and only opened the deep end skimmer. It would pull some stuff, but the skim-vac would pop off every so often. It was dark and I couldn't see what I was doing, so I stopped. The next evening, the pool water level was down towards the bottom of the skimmer so I didn't want to go to waste anymore. I decided to put on recirculate so I could pick the big stuff off the bottom (lots of pine needles). I always stop and check the pump basket and skimmer basket every time the skim-vac pops off to make sure it's not clogged. sometimes it is, sometimes it isn't. Either way this was every 3 to 4 minutes. I figured by using recirculate, this eliminates the possibility of an issue with the filter.
I noticed that while first putting the skim-vac on, I will have really good suction, so much that I can't even reposition the skim vac slightly in the skimmer, but then 3 or 4 minutes later, the skim-vac will lose suction and pop off and sometimes brown junk I was vacuuming will come out the hose and back into the pool. I'll pull the skimmer basket out to clean it out (it's usually not very full) and it doesn't seem like there's strong suction in the skimmer. By the time I put the basket back in, the suction is higher again. I also started to notice that when I first turn on the pump, the jets are spraying water, but as I get to the point where the skim-vac is not working good, I also note the return jets have very little pressure. I check the clear lid on the pump basket and there's no air bubbles. I also notice that the pump motor gets very hot (it never shuts off from thermal overload and doesn't smell). I can't even hold my hand for a second on it without burning my hand (which I'm sure is too hot). If I take the vacuum off and try to just run the skimmers, i'll see air bubbles come out the jets for a minute or so and then run perfectly fine with good pressure. The deep skimmer will have good suction and the shallow may or may not (I haven't played with the shallow end enough to see, but I think when I first turn the pump on, it's got good suction then gets weaker as time goes on). I'll try the vacuum again and it will be ok for a couple minutes and then start with the problems again. I thought the vacuum hose might be clogged, so I took my garden hose and ran water through the vacuum hose. It comes out the other end. The vacuum hose is old and had bad ends, so I bought new ends to screw onto the hose. I know they don't seal great and can hear air being pulled in sometimes as the end is near the low water level. So I decided to thread a pipe nipple onto the bottom of the skimmer (where the gizmo usually threads into for winterizing) and then hook the hose to that. This way the vacuum hose connection is fully under water and if the air leak was the issue, it would be sucking water, not air. I realize if that was the case, the vacuum would likely not have good suction, but the pool shouldn't have the other issues with the lack of return jet pressure.
Could it be that the vac hose is clogged and causing the low return jet pressure? I'm thinking of buying a new vacuum hose since the ends aren't airtight (unless you know of a way to seal these other than just threading them on). Or is it just because the vacuum hose is so long (about 50 ft) that it acts as more of a restriction than the skimmer alone. I was also thinking my motor/pump was shot because it gets so hot and figured that maybe when it's really hot, it's not pumping as strong as it should which is why suction starts out ok, but gets weaker. I haven't paid enough attention to see if this is really the case with the skimmer suction/return jet pressure though.
Now, I'm starting to think I might have an intermittent clog in one of the skimmer lines as I'm writing this because even without the vacuum hooked up, the motor gets too hot to touch (and I can hold hot stuff). It was like that last year too. I haven't tried using only the shallow skimmer to see if it makes a difference. I did notice one time that the multi-valve at the filter sounded like something was bouncing around in there and I was thinking of taking it apart, but the noise wasn't there before even though the other issues existed and the noise is gone again.
Either way, I can't get the pool clean with the vacuum I have now and we're having a birthday party in a couple weeks. I'd be interested to hear any advice you guys have! Also, I'd like to know if there's a better way to clean out the pool.