Loosing water on backwash without pump running

[ritchie-t]

HI there,

I have just bought a property with a pool and naturally have been doing a log of googling. I have probably missed something onbvious here, but when reading up on how to to do a backwash on a sand filter, it seems as simple as turning off the pump, turning the filter to backwash, turning on the pump... then repeat the process for rinse.

However in my case, with the pump off when I turn the lever to backwash, water comes out of the waste outlet before I turn the pump on. It comes out at very high pressure too, so I expect it is pressure from the main drain at the bottom of the pool perhaps?

Is this normal? It certainly does not seem right from everything I have read and videos I have viewed.

Note - Trying to identify the main drain is difficult at the moment because the previous owner has not labelled any of the pipework or valves. I could start a trail and error process identifying them all, but thought I would ask here first.

Any help is much appreciated.

Thanks,
Ritchie

[Teapot1]

Is your equipment above or below the waterline of the pool? Make sure your pressure gauge has fallen to zero before moving the valve, some loss is common due to siphonic action. Well thats some points covered.

Main drains connect in two ways usually, one on its own pipe run back to the pump. The other is into the skimmer and then a single pipe back to the pump. Look for 2 holes connected in the bottom of the skimmer (s).
Or have you a manifold of several pipes before the pump?

[Denniswiseman]

When you set to backwash all water will go to waste so if your equipment is lower than the pool surface it will run out naturally
The only option is to connect your waste port up before attempting to backwash or fitting a valve to the waste port
Probably a trial and error is the best option. Take an image of the settings before adjusting so you can go back to the origonal
Turn them all off except one, check the returns are working and see if the skimmer is sucking

[ritchie-t]

Thanks both of you for the replies.

So the pump is considerably lower than the pool, so that would explain things. I can relax now knowing that what is happening is normal

Teapot1 - To answer your question, there is a manifold of several pipes before the pump. The pool has 1 skimmer, 1 main drain and 1 which I can only assume is for vacuuming (stubby pipe sticking out in the pool). There are 3 pipes that come into 1 before the pump. All out of a concreted wall, so no way to see which is which.

Trial and error should be simple enough.

[Denniswiseman]

Once you sort it, label them for future operation
I would connect a hose to the stubby pipe sticking out in the pool unless it's under water (I dare say it is probably turned off anyway)

[Teapot1]

The stubby pipe, is it a return or a vacuum point?
Glad you are making headway.

[ritchie-t]

Managed to work out all the valves and label them all.

To answer the question about the stubby pipe. It is under water, half a meter down from the water surface. I found the valve for it and it sucks, so must be a vacuum point.

I did notice something else. The sand filter pressure gauge sits at about 4 PSI even when it is turned off. Is this any cause for concern?

[Denniswiseman]

The gauge is broken, not a hard job to replace
I think I've replaced 3 or 4

[ritchie-t]

Ill add the gauge to the list of things to fix .

I also just noticed there is no skimmer float valve.

Seems plenty of things need sorting on this pool as you have seen my other post about the CYA being really high too. I don't think the previous owner looked after it too well.

Thanks again both of you for the advice. Much appreciated.

[Teapot1]

Skimmer weir plate.

[Denniswiseman]

Ill add the gauge to the list of things to fix .

I also just noticed there is no skimmer float valve.

Seems plenty of things need sorting on this pool as you have seen my other post about the CYA being really high too. I don't think the previous owner looked after it too well.

Thanks again both of you for the advice. Much appreciated.

A lot of people just do what the pool store says without understanding anything
At least you have an idea now