RO water flow slows after 1 pint

[norbra]

I have a full pressure tank with ample air pressure.

I have removed post carbon filters ,water still flows normally for the first pint then slows to a trickle.

The on board pump starts and runs as expected.

I renewed all filters 2 months ago (75 GPD RO filter 0.75GPM post carbon filters)

The water supply is strong and clear.

Any suggestions how to troubleshoot further.

Thanks 

[gamb00ler]

When I had these symptoms on my system in USA, it was due to a ruptured bladder in the storage tank.  The bladder could not be repaired so the only recourse was to replace the tank.

[norbra]

21 minutes ago, gamb00ler said:

When I had these symptoms on my system in USA, it was due to a ruptured bladder in the storage tank.  The bladder could not be repaired so the only recourse was to replace the tank.

Thanks for your info,I will now drain the tank and see what the flow rate looks like

[Crossy]

An off-topic attempt to de-rail this thread has been removed.

 

Back-on topic, I too would be draining the tank fully, if it has an air valve pump it to the recommended pre-charge whilst the tank is empty of water.

[Bill97]

48 minutes ago, gamb00ler said:

When I had these symptoms on my system in USA, it was due to a ruptured bladder in the storage tank.  The bladder could not be repaired so the only recourse was to replace the tank.

Here too.

[VocalNeal]

Quote

 

flow slows after 1 pint

 

I have a similar problem myself in the morning????

[norbra]

Some more information

With the manual flush valve opened the water is now flowing at the normal rate ,does this point to the auto pressure device?

[peterfranks]

If it is a Mitsubishi pump, they don't have a bladder, isn't it?

[Crossy]

16 minutes ago, peterfranks said:

If it is a Mitsubishi pump, they don't have a bladder, isn't it?

 

It's an RO water filter with a pressure tank, not a water pump, but I believe you are correct.

[Crossy]

49 minutes ago, norbra said:

Some more information

With the manual flush valve opened the water is now flowing at the normal rate ,does this point to the auto pressure device?

 

Ours is auto-flush so no manual valve, but I suspect that opening the outlet whilst a reverse flush is in progress would simply bypass the RO membrane so it going full flow probably is just normal.

 

Have you drained the tank of water and verified the pre-charge air pressure?

[norbra]

39 minutes ago, Crossy said:

 

Ours is auto-flush so no manual valve, but I suspect that opening the outlet whilst a reverse flush is in progress would simply bypass the RO membrane so it going full flow probably is just normal.

 

Have you drained the tank of water and verified the pre-charge air pressure

 

 

 

 

when I disconnected the tube from the tank water gushed out at high pressure will empty tank later

[Crossy]

Our tank has a water valve on the top ???? 

Also, remember to shut off the supply inlet and electricity to the unit.

 

I cheat a little when our tank loses pressure to avoid wasting cleaned water.

 

Shut off the water and electrical supply.

 

Open the outlet tap saving the water of course.

 

When it runs dry check the tank pressure and pump up as necessary (leave the outlet open and catch any more water that exits).

 

Close the outlet, turn on the supply and power and let things get up to pressure again. 

[norbra]

1 minute ago, Crossy said:

Our tank has a water valve on the top ???? 

 

Also, remember to shut off the supply inlet and electricity to the unit.

SOP but thanks for the reminder

[norbra]

1 hour ago, Crossy said:

Our tank has a water valve on the top ???? 

Also, remember to shut off the supply inlet and electricity to the unit.

 

I cheat a little when our tank loses pressure to avoid wasting cleaned water.

 

Shut off the water and elecrical supply.

 

Open the outlet tap saving the water of course.

 

When it runs dry check the tank pressure and pump up as necessary (leave the outlet open and catch any more water that exits).

 

Close the outlet, turn on the supply and power and let things get up to pressure again. 

When I removed tank to more convenient area opended the outlet and got a bit more than half a pint from internal pressure I think end of story time to get a pump and guage.

No sign of water bubbles when i pressed air valve just a whisper of air pressure 

[Crossy]

3 minutes ago, norbra said:

When I removed tank to more convenient area opended the outlet and got a bit more than half a pint from internal pressure I think end of story time to get a pump and guage.

No sign of water bubbles when i pressed air valve just a whisper of air pressure 

 

Yeah, looks like your tank has lost pressure. Does it have a label with the pre-charge pressure? If not try 40psi (nip it down to the garage to pump up).

[carlyai]

Yes need to pump up at the garage.  My RO unit did the same, so pump up fixed it.

[Crossy]

Note:- A quick peruse of various on-line sources shows them quoting a pre-charge of 10psi or so which seems low to me.

 

Too much pre-charge will limit the amount of water your tank can hold, same problem as no pre-charge. Nothing to stop you letting some air out if you find you are getting too little water.

 

Obviously if your tank has a label, follow it.

[norbra]

38 minutes ago, Crossy said:

Note:- A quick peruse of various on-line sources shows them quoting a pre-charge of 10psi or so which seems low to me.

 

Too much pre-charge will limit the amount of water your tank can hold, same problem as no pre-charge. Nothing to stop you letting some air out if you find you are getting too little water.

 

Obviously if your tank has a label, follow it.

Tank label shows

 Empty 5-7psi 

Full 40psi

[Crossy]

Just now, norbra said:

Tank label shows

 Empty 5-7psi 

Full 40psi

 

5-7psi it is then ???? 

 

[gamb00ler]

8 minutes ago, norbra said:

Tank label shows

 Empty 5-7psi 

Full 40psi

I remember that I had to buy a special low pressure tester to be able to measure the tank pressure when empty.  I came across it when I wanted to check our tire pressures as it looks exactly like a normal tire pressure gauge except for the scale labels.

[norbra]

1 hour ago, gamb00ler said:

I remember that I had to buy a special low pressure tester to be able to measure the tank pressure when empty.  I came across it when I wanted to check our tire pressures as it looks exactly like a normal tire pressure gauge except for the scale labels.

Thanks but I'm currently looking at digital guages

[carlyai]

29 minutes ago, norbra said:

Thanks but I'm currently looking at digital guages

I think I just used my normal tyre guage for the car.

[norbra]

On 7/11/2022 at 8:46 AM, Crossy said:

 

5-7psi it is then ???? 

 

Sad story empty tank is still full of water.

Now looking for new tank thanks everyone for your input

 

[Crossy]

Ours just sprang a ruddy leak so it's dribbling all over the kichen floor, it evidently heard us talking about it.

 

Madam put a towel under it and I ordered a replacement - https://www.lazada.co.th/products/i1508658372-s3987020350.html

 

[norbra]

30 minutes ago, Crossy said:

Ours just sprang a ruddy leak so it's dribbling all over the kichen floor, it evidently heard us talking about it.

 

Madam put a towel under it and I ordered a replacement - https://www.lazada.co.th/products/i1508658372-s3987020350.html

 

IJust ordered this model too my system only 20 months old

 

 

[Crossy]

17 hours ago, norbra said:

IJust ordered this model too my system only 20 months old

 

Ouch, just out of warranty of course.

 

Ours managed 10 years before rust got the better of it.

[Crossy]

New tank has been delivered, I'll put it on tonight after work (yes, working whilst everyone else is on break).

 

[norbra]

30 minutes ago, Crossy said:

New tank has been delivered, I'll put it on tonight after work (yes, working whilst everyone else is on break).

 

Mine has also been delivered, installed and now filling.

That's my second tank in 10 years,first one from Homepro rusted out 2 years ago

[norbra]

1 hour ago, norbra said:

Mine has also been delivered, installed and now filling.

That's my second tank in 10 years,first one from Homepro rusted out 2 years ago

Long time since I "played" with an accumulator (to maintain pressure in a  system during medium(oil) losing heat and contracting) Government requirements for passenger elevators..

So I sort of expected that filling the new tank would take a while due to restricted throughput of ro membrane maybe the pump has stopped due to no water to pump..

At my age I still have a thirst for knowledge,how it works and how to fix it

[carlyai]

4 minutes ago, norbra said:

Long time since I "played" with an accumulator (to maintain pressure in a  system during medium(oil) losing heat and contracting) Government requirements for passenger elevators..

So I sort of expected that filling the new tank would take a while due to restricted throughput of ro membrane.

At my age I still have a thirst for knowledge,how it works and how to fix it

I'm similar vintage. Did you ever work out how to successfully get a condom on? I couldn't. ???? Mabe the new Woke ones assemble themselves on the shaft? ????