No water circulation and high pressure in the filter

I noticed yesterday that my water circulation at the bottom end of the pool was not working.

I checked in the pump house and discovered that the filter pump was very hot. I switched the system off and opened it up. Removed the filter basket, which had some debris in it. I emptied the basket, washed it out and replaced it. As it was so hot I decided to leave it off until today.

Today I switched the filtration system on and was pleased to see the water circulation came gushing out. Sadly it was short lived and virtually stopped.

I went to the pool shed and noticed the filter pressure was almost at the top of the red (very high).

We then did a backwash and switched the system back on again. The water circulation started up, but was short lived and the pressure on the filter was very high again.

This system is only a year old, so I don’t really understand why we are having this problem or how to sort it out.

Please help me. I know very little about pools.

Hi. We found the booklet that came with some of the pool equipment and it says that the pump should be below the water line (as you said).

Martyn has to prime it about every 5 days, but then it runs OK.

It would be good to see you and perhaps have our minds put at rest that that we are doing things right. I am out Saturday and Sunday mornings, but we should be around afternoons if you are free. We will leave it up to you.

Hi Freya,

Your brother could be correct although just conjecture without examining the system.

If Martyn has to fill the pump to prime it, can I assume the pump is above the water line?

Due back in France this week end of, subject to travel problems I will try to make it over at some point.

Hi John,
We think that the water pressure may well have been quite high from the beginning, but we really are not sure.

We sometimes find the pump doesn’t want to fill with water, so Martyn fills it from the pool and then all seems to work well.

My brother, an electrical engineer, reckons that there are possible air locks in the system and thinks this might be due to so many bends/corners in the pipe work.

Might this be the case?

Oh how I dream of the loose end, my next trip probably this weekend is still tight on time. Was the pressure always a bit high? I am afraid the pool industry is very much see monkey do. The real engineers and water techies are few and far between.

Hello again.

The pool is functioning pretty well at the moment, but the pressure in the filter is still very high.

We did wonder if part of the blockage might be from the glass UV which blew last year. I don’t think we have any way of getting that out.

Maybe if you are “at a loose end” one day you might pop over to have a look? It would be greatly appreciated.

Hello Nohn,

My husband investigated the “blockage” and found it between the uv and the chlorine block container. It was some of the algae that obviously slipped through the net when we cleared out the horrendous mess from a. Onto or so. He thinks he has cleared it, although he says the filter pressure is still in the red.

I have just arrived back from Provence with relatives, so will look at it tomorrow when the system is running.

I will keep,you posted as to the state of things.

Enjoy your lawnmower fixing!
It doesn’t seem that it is quite so urgent.

I can't promise as the curse of being able to mend things is I am already booked to repair a lawnmower Friday pm, Have to see how things go.

I don’t suppose you would come round on Friday and have a look just to check we aren’t doing anything stupid.

I will then contact them as you have suggested.

I would invite Thermapool to carry out their warranty obligations no matter what you think they have a duty, if they don't wish to attend (sure they won't at their expense) tell them you'll sub contract another engineer and pass them the bill!

That sounds pretty bad news. I don’t really want to go back to Thermapool to solve the problem!

At 3 bar it's quite likely you'll have leaks that won't be there at 1-2 bar.

it could be anywhere from the return jets where they join, right back to the filter.

So could it be that the blockage might be mear the leakage in the uv filter? Or perhaps just past it? Today is the first time it has leaked.

We also have a small leak coming from the filter. It is a regular very small trickle.

Understood, It appears you have a blocked pipe somewhere, possibly this has become crushed unless there is a valve not open on the return side somewhere.

The return jets did look as thought they were starting up, but I am not happy to leave the system running with water pouring over the pump

I put it on recirculation and the pressure started at 2.2.

After a very short time the pressure started going up to 2.3 and then the uv started leaking.

I have switched it off again

I am not surprised it's leaking at 3 bar it's a good safety valve before something else goes, sand filters when they split are something else!

I am not around until Friday PM

I would ask you to try putting the filter on recirculate and let me know the pressure and the return jets flow does it feel good or weak?

Hi John,

Thanks for your reply.

We have now back washed and rinsed and the water is clear. We now have the problem that the UV filter is leaking! The leak is right over the pump, so we have had to switch everything off.

The pressure on the filter is around 3, which is still high in the red.

I don’t suppose you are around or could recommend a pool technician in the area. Technically we are still under warrantee, but after having to get solicitors involved because of Thermapool trying to sting us for more money which was not agreed at the time of doing the work (part of their agreement) I don’t feel I can phone them or even trust them.

Freya how long did you backwash for? There should be a sight glass on the filter valve, it often takes a minute or two for the sand in the filter to expand enough to release the dirt and show as dirty water in the sight glass. With the reading you have nearly in the red it may take 5 mins to really clean the sand in the filter. You need to see the sight glass run clear for a minute after the dirt has left. Often good to hold a piece of white paper under the sight glass to make it easier to see.

Once you have finished the backwash, do a minute on rinse to re settle the filter sand before setting back on filter.

Remember to stop the pump before moving the filter valve handle.

Hello John. I am in France on my own but my son and his fiancée have just joined me. We are having problems getting the water to clear in the pool.
I started off two weeks ago with a greenish pool. I added flocculant and the liquid chlorine. I tested the water and thought the ph was too low so added ph+.
We have been trying to get the ph and chlorine levels right and I’ve done at least 4 backwashes Iver the last fortnight. The water from the backwash doesn’t seem dirty but maybe I’m not doing it for long enough.
The water now looks the right colour - a crisp blue - but it is still cloudy.
Any suggestions gratefully received.