Flow drops from 60 to 7 after 8 minutes!

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S

SudsMalone

0
Mar 26, 2011
26
Melbourne, Australia
Hi,

I am pretty new to pool speak so please forgive me if I get some of the terms wrong......

We have a fiberglass salt pool, which our pool pump (Hurlcon) recently carked it (didn't run at all), it was still under warranty and replaced.

Since the new pump has gone back in when our pool starts up there is lots of pressure (anywhere between 50 & 70 on the gauge) and the vacuum works, if we have it switched over to waterfall we have 3 strong flows. But after about 8 minutes (approx) every time without fail the pressure drops to about 7, from the the vacuum hardly does anything and if it is in waterfall mode we only have 2 week flows instead of 3 strong ones....

Our pool is green as it has been out of action for minimum 3 weeks now. We are at a loss as what to do and the Hurlcon people don't care.

The basket is empty and the big filter is clean as well.

This pool has been a total nightmare since installation (mainly due to the pool company that installed it and their lack of customer service) and when we run in to troubles our pool is out of action with little help for weeks on end. We probably only have a couple of days left before the colder weather sets in and we can't use the pool. Any advice greatly appreciated. I so want to use it and am SICK of looking at a green pool! :(

Thanks in advance.
 
I would say you have more than one issue.

1) Green pool means a chemistry imbalance and/or a lack of circulation.
2) Green pool and a pool sweep don't mix. Sweeps help keep a clean pool clean. They won't clean a dirty (i.e. green) pool.

Where are you located?

Tell us more about your pool, it's equipment and it's chemistry levels. What are you using to test your water with?

The 50 to 70 number on your gauge is measuring what? Flow? In GPM or LPM?

I will assume you meant flow for the moment.

Is there air in the pump basket? Is it surging or just slow? If it surges, either the water level in the pool is low and you are sucking air in the skimmer or the skimmer weir (flapper) is stuck. If it's just slow and the tank pressure is high, the filter is dirty. If the tank pressure is low, either the impeller is clogging, broken, or the suction line is obstructed or collapsed.

Scott
 
Hi and welcome to TFP!. I'm sorry you are having so many problems, lets see if we can help you out. I have a few questions about your pool and equipment that will help us find out what is going on.

If you can edit your signature and add the following information, it will show up in each post. pump horse power and brand, filter type (sand, DE, cartridge) size and brand, pool finish and size in gallons or liters, water features, type of water sanitation used (chlorine, bromine, baquacil, mineral packs, ionizers, ozone) additional equipment (heaters, automatic cleaners, pop ups, solar pannels, ect) Your general geographic location (city, state, or region, country if outside the U.S.)

Back to your problem. Is the water level in the pool at least 1/2 way up the skimmer opening? When the pump is 1st turned on and pressure is strong is the pump basket full of water? When the flow from the pump drops does the water level inside the pump drop? Does the sound of the pump motor change when the pressure/flow drops? Has the plumbing been checked for leaks or obstructions?

Any pictures you can post of your pool and equiment may also be helpful for troubleshooting.
 
Hi Scott,

Thanks for the response.....

Point 1 I would agree it is both.
Point 2 I disconnected the vacuum

I am in Melbourne Australia.

I really do have limited knowledge on the pool, it is 8 x 4 meters fibreglass with a salt chlorinator. We took a sample of the pool water to the pool shop to have tested, they gave us instructions to add 'sodium bicarb', hydrochloric acid, chlorine & salt which we are following those instructions.

The pressure gauge that I am talking about is on top of the large filter (PSI and KPA written on it and it goes to a maximum of 250. I have seen it start at 100 and in my opinion running at 70-100 is probably what it is suppose to do)

Yes there is air in the pump basket (but I also think that has always been the case) and everything appears to be flowing around. The air in volume I suppose would be the size of a cup, this is consistent in volume whether pool is on or off. When the pressure is high the water is fast and when it drops the water slows down.

I don't think the pool water is low as it covers the pool vacuum when it is connected to the filter and I can't see air getting in there. (I have disconnected the vacuum now and it does stop after short time still)



G'day Zea,

I will update my signature tomorrow, it is 10:30 at night so a bit dark near the pool to get some info... I keep running out with a torch lol

In answer to your questions:

Is the water level in the pool at least 1/2 way up the skimmer opening? Yes
When the pump is 1st turned on and pressure is strong is the pump basket full of water? There is about the volume of 1 cup of air in there which is consistent however the pump is (on or off)
When the flow from the pump drops does the water level inside the pump drop? Not sure what you mean, if you mean inside the pump basket, no it is consistant.
Does the sound of the pump motor change when the pressure/flow drops? Yes, but it sounds like the change of pressure dropping off.
Has the plumbing been checked for leaks or obstructions? No, we did have a pool guy out to inspect the pump (who told us it died and to get it fixed under warranty), he didn't find anything wrong with anything else and charged us $165 for the experience (we can't afford him again!).

Thanks again :)

(It just seems very strange that the pressure drops after a certain amount of time every single time. Could there be some sort of cut off or protection on the pump?)
 
KPA is not commonly used by most of us here in the states. PSI is a measure most of the technically inclined are more familiar with. Fortunately, I found an online converter at http://www.csgnetwork.com/presskpapsicvt.html

If it's surging, it's likely to be sucking air intermittently. That would indicate the flapper in the skimmer getting stuck in an elevated position, either from debris or the walls of the skimmer mouth being too close.

If the pressure drops off steadily from the 70 to from 7 and holds there, there is a restriction either in the impeller or in the line.

After physically disassembling to check the impeller isn't having an issue, my next thing to check would be the suction side line(s) and valves.

I would blow the line to see if a physical obstruction gets blown out, likely through the skimmer. If that works, great! If not, it's possibly kinking under suction if flex-pvc was used or the obstruction is too big to get past an elbow.

Scott
 
Look for an air bleed valve on the top of your filter. Open it up with the pump running util it squirts out a steady stream of water. This should allow your pump basket to fill completely with water. You may need to do it a second time to make sure all the air is out of the system. See if this helps.
 
Thanks all for your replies!

Scott - I don't think we have a flapper in the skimmer, we also don't have a way of emptying the pool. The local pool maintenance people quoted us a couple of hundred dollars to have the backwash installed. I do not know why the pool didn't come with a way of emptying it. When we had some floods recently, I had to put in a hose, and suck the water out the old fashioned way!

How do you 'blow the line'? I understand what you're getting at, is that something we can do ourselves (a 2 minute backwash) or do we need an expert? When the pump is flowing, it goes on 'normal' pressure for about 5 minutes (we re-timed it) and then goes to a trickle. I wouldn't call it intermittent.

Gordiec - Yes, it is the same if we have the waterfalls on or off. If we just have the waterfall on, it loses pressure after 5 minutes, if we have just the pump on, it does the same.

Zea3 - we did that and it got rid of the airbubble, but it had no effect on the problem, it still slowed to a trickle after 5 minutes. We checked the filter to see if it was clean (which it was) and then re-did the bleeding, but couldn't totally get rid of the airbubble that had reformed.
 
By "blow the lines" I think he means to force water backwards through the pipes to flush out whatever it is that is blocking the flow. Some people used a hose attachment called a Drain King. Water pressure from the hose expands it and seals it against the pipe and then it lets the water through to flush the line. Here is a link with a picture:
http://www.amazon.com/Water-Prod-501-Drain-Opener/dp/B0000CBJ66
 
A little more on blowing the lines -- I think Scott means to blow them from the pump back towards the skimmer, which is where the pump pulls the water from the pool.

Just out of curiosity -- do you have a basket in your skimmer(s) and if so are they clean?
 

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do you have an experienced electrician available? a similar issue locally (actually several separate instances..) were due to incorrectly wired pump(s) for 240v vs 120v

study also the recommendation to blow the line(s).
 
I'll get it checked out, my uncle is an electrician so I'll get him to look on his next visit.

We are also going to the manufacturer under warranty to see what happens, we are convinced it is that and the local pool repair guy suggested this to us yesterday as well. Just too much of a coincidence that flow drops at 5 minutes every time........ will let you know and/or will be back for more answers if it doesn't help.....
 
Maybe you already tried this, but once the flow slows down, try bleeding the air out of the filter again. If you get a bunch of air out and the flow goes back to normal (for another 5 minutes), then air getting into the suction side of the plumbing is the primary problem.
 
no we hadn't tried that as we only got the air out when it was going at full speed...... I just tried it on the slow flow as you suggested...... didn't work :( Actually we can't get the air out full or slow flow now

the pump people are coming tomorrow to have a look

(Scott we haven't tried all of your suggestions as they were technical for us newbies and we hope it is a simple matter of pump malfunction, warranty takes over! If not we will be back with a truckload of questions! :))
 
Yeah it's fixed!

The pump people (Hurlcon) came back out today and had a look. Turns out that there is a button that changes the flow setting. 5 minutes full flow then rest of the time slow flow (for winter), then there is medium flow or fast flow. By default winter (slow flow) after 5 mins is the default setting.

(And before you shoot us for not seeing this........ the button to press is completely out of sight and you need to be a contortionist to get to it! The installers did not tell us about this button and for that matter didn't even think about access to it to change the settings...)

The pool repair guys had never heard of this button, and when we rang Hurlcon (a few times mentioning this problem) they didn't tell us this over the phone, apparently there was no slow of speed/flow button! So I don't know if we fluked it today with the right guy coming out and just got the 'yeah yeah whatever' people when we rang up.

But the good news, super easy fix!

Thanks for everyone for their advice we may not have fixed this problem but we have learnt a lot about our pool that will help us in the future!
 
aaaahhhhhhh I am at "I hate our pool" stage now!

I am not sure if I should continue in this post or start another as my hunch they may be linked.....

We have now lost pressure again.

It actually worked fine for a whole afternoon and into the night, when we woke this morning the pool was off.

When we start it up we have a pressure reading of 20psi, this remains steady.

However there is minimal suction and on the 'return jets' we have bubbles. The pump basket is only slightly over 1/2 full of water and is surging. I know that this all points to an air leak. But how could this happen so quickly?

I can't understand how could this have happened? Everything only just started to work again. Since working to now all we have done is, added 12 cups of chlorine to get rid of the green (our pool is now 'milky' in color which I can gather that may be dead algae). - Could putting in too much chlorine cause this problem?

The vacuum has been running and the basket has been emptied. (There is little suction whether vacuum is in or not)

There is also some air in the chlorinator cell (did I get that right? the big clear tube) about a cup full in volume I suppose. Is it OK to have air in here or should it be only water? Could this be causing the problem at the pump?

Prior to pressing the button on the pump to get it going for longer than 5 minutes (see other post)! We checked the chlorinator filter to make sure it was clean, but that was prior to working. I have checked to make sure we secured the lid.

Help pleasssssseeeeee I need the most basic things to check first...... (water level is fine now 3/4 skimmer level, I also poured water over pump to check for leaks and didn't notice anything)

Very importantly should I leave the pump running or off while this is happening? I don't want the pool going green again but I don't want to damage anything either........
 
What kind of filter do you have and did you clean it after this current issue popped up? Since you started killing algae, it can clog the filter fairly quickly, restrict flow, and increase pressure.
 

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