Stainless steel fresh water tank problem

[Cartel]

Recently our water system has been acting oddly. Until a couple of months ago the tank would give a resounding bang when first filling and then again as it was nearing empty (the Jabsco water pump goes into very noisy spasm as it can't get water in.)

What is happening currently is that we have got to the stage where after a couple of showers and a load on the washing machine the tank seems to run dry and needs filling but, here's the odd part. when I try to fill it again It overflows at the filler cap after only 10 minutes, seemingly being full but it will be empty after less than a day's usage, also the banging is much more frequent maybe 10 times during the one day. Before now it would take about 45 mins to an hour to fill it.

Any suggestions would be greatly appreciated.

Thanks

Tel

[Russ T]

Leak in tank?

 

Blocked overflow pipe?

Kink in filler tube?

[Momac]

Blocked breather 

But the banging may be normal

[Cartel]

Thanks Russ, I did think about a leak but why does it take such a short time to fill it, if there was a leak it would take longer, I'm thinking. The filler tube is not kinked as I can see the whole length of it and it's about 50mm thick.

The overflow pipe, I'm not sure where that is as I ca't get to the whole tank.

2 minutes ago, Momac said:

Blocked breather

The tank is under our bed and quite difficult to get at, not sure where I find the breath. Where is it likely to be?

[Momac]

3 minutes ago, Cartel said:

 

The tank is under our bed and quite difficult to get at, not sure where I find the breath. Where is it likely to be?

My first guess would be the breather is near the filler .

 

[Kingdom Isambard Brunel]

Dip tube pick up pipe in the tank fallen off?

[bizzard]

8 minutes ago, Cartel said:

Thanks Russ, I did think about a leak but why does it take such a short time to fill it, if there was a leak it would take longer, I'm thinking. The filler tube is not kinked as I can see the whole length of it and it's about 50mm thick.

The overflow pipe, I'm not sure where that is as I ca't get to the whole tank.

The tank is under our bed and quite difficult to get at, not sure where I find the breath. Where is it likely to be?

In the filler neck.

[jonathanA]

When you open the filler do you get a "whoosh" as air enters it?  

 

Sounds like a blocked or non-existent breather. Maybe try leaving the filler cap a bit loose so it's not an airtight seal and see if that makes a difference. 

[Richard T]

Our stainless tank used to bang when being filled. Eventually a weld failed - new tank then needed. So beware!!

Investigate where the breather is -it might mean dismantling part of your bed

[Jen-in-Wellies]

Also, if the breather is blocked, the tank may have imploded due to the low pressure inside when the pump runs. This may have distorted the tank so it can no longer hold the same volume of water. It would fit what you are describing. Alternatively, the blocked breather means that water can't fill properly, as the air can't get out to make room, leading you to think it is full, when it isn't.

 

I had this happen on a car petrol tank with a blocked breather pipe. The fuel tank had collapsed so much they fuel gauge sender float was being held up by the raised up centre of the tank bottom face. The gauge needle wouldn't drop below an indicated half full, when In fact it was empty and I ground to a halt. New tank needed 

 

The only way to see what has happened to your water tank is to dismantle around it and look. Check and unblock the breather too. Hopefully the tank itself is ok.

[IanD]

38 minutes ago, Jen-in-Wellies said:

Also, if the breather is blocked, the tank may have imploded due to the low pressure inside when the pump runs. This may have distorted the tank so it can no longer hold the same volume of water. It would fit what you are describing. Alternatively, the blocked breather means that water can't fill properly, as the air can't get out to make room, leading you to think it is full, when it isn't.

 

I had this happen on a car petrol tank with a blocked breather pipe. The fuel tank had collapsed so much they fuel gauge sender float was being held up by the raised up centre of the tank bottom face. The gauge needle wouldn't drop below an indicated half full, when In fact it was empty and I ground to a halt. New tank needed 

 

The only way to see what has happened to your water tank is to dismantle around it and look. Check and unblock the breather too. Hopefully the tank itself is ok.

I had the same happen with a car fuel tank, which ran out of fuel on an isolated road in the Dales which the RAC claimed didn't exist -- at least, not according to their computer.. 😞

 

When the patrolman finally turned up he immediately knew what the problem was -- "Oh yes, Vauxhall Carltons, we've had lots of them do this..."

Edited May 27 by IanD

[Cartel]

Thanks for all the suggestions, it's giving me things to investigate.

 

I started with the filler pipe. The filler doesn't have any breather, it's just a screw cap on the top of the filler tube, no vents on it.

Last might I made a marker on the filler tube (about 100 mm down from the filler cap) and didn't run any water overnight and this morning the level was the same as last night's mark, which I think, maybe says that there isn't a leak.

When a tap is opened, this level is going down a tad, which shows water going into the tank.

I just videoed a test where I marked the level and used a sink plunger on the filler hole to see if any blockage needed clearing. The result was that as I pushed the plunger down the level went down but a I stopped pushing the level then went up above my mark and then settled at the original level. (I guess thats just the tube expanding as I push down.

The next step now is to dismantle the bed and see if I can see any breather port.

 

Tel

[David Mack]

1 hour ago, Cartel said:

I just videoed a test where I marked the level and used a sink plunger on the filler hole to see if any blockage needed clearing. The result was that as I pushed the plunger down the level went down but a I stopped pushing the level then went up above my mark and then settled at the original level. (I guess thats just the tube expanding as I push down.

That would be consistent with the filler tube going down part way into the tank and there being a giant air bubble in the top of the tank, caused by a blocked breather.

Edited May 28 by David Mack

[blackrose]

18 hours ago, Cartel said:

Recently our water system has been acting oddly. Until a couple of months ago the tank would give a resounding bang when first filling and then again as it was nearing empty (the Jabsco water pump goes into very noisy spasm as it can't get water in.)

 

 

I don't understand. Why was it banging? If the breather was letting air in/out properly should it do that?

Edited May 28 by blackrose

[jonathanA]

5 minutes ago, blackrose said:

 

I don't understand. Why was it banging? If the breather was letting air in/out properly should it do that?

9 out of 10 cats prefer to think the breather maybe blocked.... OP is investigating whether there is a breather and whether its blocked. 😂

[Kingdom Isambard Brunel]

The majority of stainless steel water tanks are made from very thin sheet. They have large flat areas without bracing or embossed patterns so that they flex like balloons. It is common for them to boing and bang.

The fact that this tank has recently been banging more than ever would suggest that it is imploding due to a partial vacuum inside caused by the vent being blocked and the pump trying to empty the tank.

I fear that its is going to be expensive to repair.  The very careful use of compressed air may restore its capacity.

[Tony Brooks]

17 minutes ago, Kingdom Isambard Brunel said:

The majority of stainless steel water tanks are made from very thin sheet. They have large flat areas without bracing or embossed patterns so that they flex like balloons. It is common for them to boing and bang.

The fact that this tank has recently been banging more than ever would suggest that it is imploding due to a partial vacuum inside caused by the vent being blocked and the pump trying to empty the tank.

I fear that its is going to be expensive to repair.  The very careful use of compressed air may restore its capacity.

 

Or a big sucker like the glaziers and some body shops use. Clamp on and pull the dent out, using a rope around a length of timber as a level if needed.

[blackrose]

1 hour ago, Kingdom Isambard Brunel said:

The majority of stainless steel water tanks are made from very thin sheet. They have large flat areas without bracing or embossed patterns so that they flex like balloons. It is common for them to boing and bang.

 

 

I see, no wonder we hear about the welds flex cracking from time to time. Sometimes I'm glad I've got an integral tank - until it's time to repaint it!