trying to diagnose filter problem.

[ihatemypool]

First post here--have learned a lot from this site, and appreciate all the generous advice I've been reading. Did a search but couldn't find this exact topic.

I should preface this by saying I'm currently in the middle of a bacquacrap to chlorine conversion, in case that makes a difference. I'm having a problem with my pumping system that developed at the end of last season and still remains.

I'm getting poor water velocity from my return line. It's probably about 30% of what it is when the pump is working well. Here's what I've tried, and the results.

--"Bypass to pool" produces slightly better return rate out of the return line, but still, at best, half of what is should be if the system were working well.
--Backwashing and rinsing send very little water out of the waste line. The water velocity is so poor that it's barely enough to push water through the length of the waste hose.
--Filter is not running well enough to get the vacumn to work for more than a minute or so at a time, and then very poorly.
--Bypass to waste works much better, as far as water velocity from the waste line (I'm still not convinced it's 100%, but it's much better than "backwash"), but for some reason I can't get the vacumn to work at all when using this option.

Sand is brand new. Installed along with clean laterals two days ago. When I emptied out last season's sand, it had green algae in it, and the old laterals (I've got two sets--long story) were plenty clogged with green gook. But I'm having the exact same problems with these clean laterals.

Think my pressure gauge is busted, but it reads 40 when filter is off, and 45 when running.

Any ideas of what I might be dealing with here? Thanks in advance for whatever wisdom you can offer.

 

[mofoism]

is your pressure gauge on the filter? if so it shouldnt have any reading while its off...

possible leaks?

 

[spishex]

Given that 'bypass to pool' doesn't solve your issue, this is not a filter problem. Sounds like you've got a blockage, either in your pump (check the strainer basket and impeller) or in the plumbing itself.

 

[ihatemypool]

Thanks for the replies. Strainer basket is clear. We cleaned out the impeller August of last year, and that briefly seemed to solve the problem, but by September the troubles resurfaced. We looked at it again after closing the pool, and there were no blockages.

Pressure gauge is on the multiport valve, I believe--the one that screws onto the sand filter itself. As I said, I have to believe that it's busted and needs to be replaced, since it shouldn't read 40 when filter is turned off.

I just discovered this morning, however, that my hose going from strainer basket to pump trap appears to have a leak. I never noticed it because it disappears when the pump is running, and only appears when the pump is turned off. Could this be my issue?

Thanks again.

 

[launboy]

I just discovered this morning, however, that my hose going from strainer basket to pump trap appears to have a leak. I never noticed it because it disappears when the pump is running, and only appears when the pump is turned off. Could this be my issue?

Thanks again.

You may have just nailed the problem. If the hose has a leak it will suck air when the pump is running and cause the loss of performance you speak of. Do you see lots of bubbles in the pump strainer basket when it's running?

Adam

 

[ihatemypool]

Thanks for everyone's suggestions so far. This evening's efforts have been a series of good news/bad news scenarios.

I changed the hose leading from the skimmer to the pump, and there was no change in return velocity (bad news).

I relubed and re-tightened the trap basket and the o-rings on the hose leading from pump to filter. The result was a definite jump in return velocity--by about 15% or so? (good news).

When I was working, though, I noticed water gathering on the base of the pump assembly. I thought it was the hose, so I dried everything off, looking for the leak. Well, it wasn't coming from the hose fitting, and doesn't appear to be coming from where the trap meets the pump. Instead, the water appears to be coming from the large circular assemply, just behind where the trap threading meets the pump. (the volute--is that what it's called?) Anyway, the leak almost seems to be right where the bottom of that piece meets the pump base. (Bad news, im guessing )

Does anyone have any idea what I'm dealing with here, and what my prospects are for this being a minor versus a major problem?

Thanks in advance for your help.

 

[launboy]

Instead, the water appears to be coming from the large circular assemply, just behind where the trap threading meets the pump. (the volute--is that what it's called?) Anyway, the leak almost seems to be right where the bottom of that piece meets the pump base. (Bad news, im guessing )

Does anyone have any idea what I'm dealing with here, and what my prospects are for this being a minor versus a major problem?

Could you snap a pic and post it? That leak is probably what is causing the lose of flow. It's probably sucking in air there. This might be a simple fix or the housing might be cracked and you may need a new pump.

Adam

 

[crabboy]

A suction side leak would cause bubbles in the pump basket and possibly the pump to loose prime, those would be pretty obvious symptoms. A pressure side leak would not cause flow problems like this.

Are you sure nothing is in the impeller? My wifes hair wreaks havoc on my pump, gets stuck in the impeller and drops the pressure sometimes by 10psi. I need to cram my hand into the pump to clean it out. While I don't see flow as poor as you do, it still causes a noticeable difference in the returns and when there's a ton of hair in there I can hear a difference in the pump.