Coldwater Accumulators - 1 not filling

[Skiddaw]

Hi,

First post, just joined in the hope someone may kindly be able to help with the problem as per the thread title. I will explain the setup:

On non mains water into holding tank then fed into house, into 2 accumulators via a Mainsboost charger. Been working fine for many years. During recent cold weather the external pipes/tank froze. This happens quite often due to being in an area which has very cold weather. Once defrosted everything normally kicks back in working. This time we received an error on the mainsboost charger saying it had failed. It had indeed failed and has now been replaced. So onto the issue, following the charger replacement, only 1 of the accumulators is filling. Plumber has checked everything he thinks and ST (Stuart Turner) tech help have been very helpful but to no avail.

Having tested the diaphragm in the vessel which is not filling, there is no water coming out of the schrader valve so the presumption is it is fine. All inlet valves are open to the vessel.

There has been lots of mentions of the vessel pressure. Today the readings for the 2 vessels were 0.95 bar for the one filling and 1.2 for the other one. The suggestion was to set the pressure to be the same for both which we have done. The mains pressure reading is 1.5 bar, so am I right in thinking the differential will mean the pressure on the vessels needs to be lower?

On setting the pressure on both vessels to 0.95bar and restarting the charger the same thing happened, only 1 vessel filled. If we shut off the inlet valve to the vessel which is filling and only leave the other one open, still no water goes into it. The charge continues running until the auto 180min cutout kicks in.

I really am hoping someone can help. Is there anything else, obvious or not, which is likely? We are in a very rural area and finding plumbers who can help is proving difficult. ST do not have any technicians anywhere in the county.

Many thanks in advance.

 

[Timmy D]

Have you got any pics of the set up/piping you can post?

 

[Skiddaw]

Have you got any pics of the set up/piping you can post?

Thanks for the quick reply, the tanks are in a dry (but dark) cellar so no photos this evening. I can describe the setup if that helps at all, more than in my opening post?

 

[Skiddaw]

Actually just found an old photo of the setup, the cold mains and filters were in situ prior to the installation of the vessels and charger.

 

[ShaunCorbs]

Have you fully emptied the accumulators and reset the pressure in them ?

 

[John.g]

What is the pre charge pressure and what is the final pressure?

 

[Skiddaw]

Have you fully emptied the accumulators and reset the pressure in them ?

Turned of the mains feed and the charger then fully emptied the accumulators. Measured the pressure and then changed the pressure so both vessels now 0.95 bar. The same happened only one filled. Not sure if relevant but it is the vessel closest to the charger which is not filling. Thank you for the reply.

 

[Skiddaw]

What is the pre charge pressure and what is the final pressure?

Do you mean on the vessels or what pressure the charger reaches? Apologies if stupid question, obviously I am a little out of my depth here.

 

[ShaunCorbs]

Did you leave the drain open when you emptied all the air out and re set the pressures ?

 

[Skiddaw]

Did you leave the drain open when you emptied all the air out and re set the pressures ?

So sorry I am not sure what you mean by the drain? And do you mean all the air out of the accumulators or any air in the pipework?

 

[ShaunCorbs]

The accumulators need to be empty of water eg fully drained for you to be able to check / set the pre charge / pressure in them

Turn the mains off

turn the valve off from the outlet of the acc

so there should be a drain on the pipework out of the accumulators this needs to be opened then you need to wait till the water stops

then press the shrader valve on one of the accumulators you will hear it hiss and water will come out of the drain wait until this stops then do the other one

water should come out of both

then you can set the pre charge pressure, should be the same as your standing pressure eg your water mains

 

[John.g]

Do you mean on the vessels or what pressure the charger reaches? Apologies if stupid question, obviously I am a little out of my depth here.

yes, the pressure the charger reaches.

 

[Skiddaw]

The accumulators need to be empty of water eg fully drained for you to be able to check / set the pre charge / pressure in them

Turn the mains off

turn the valve off from the outlet of the acc

so there should be a drain on the pipework out of the accumulators this needs to be opened then you need to wait till the water stops

then press the shrader valve on one of the accumulators you will hear it hiss and water will come out of the drain wait until this stops then do the other one

water should come out of both

then you can set the pre charge pressure, should be the same as your standing pressure eg your water mains

Thank you again. Did everything you mentioned in your post, however I do not believe there is a drain from the accumulators. We only have the open/closed valves on each of them. The Schrader valves hiss air, this is where I checked the pressure with a digital gauge.

So as you say the pre charge pressure should be the same as my mains (even though not on mains water) so in this case 1.5bar? So if I empty the one vessel with water in again up the pressure on both then try again?

 

[Skiddaw]

yes, the pressure the charger reaches.

During normal use the charger reaches between 2.7 - 2.9. After the new charger fitted, the charger auto stopped after 180mins and was at 2.7. Thank you

 

[John.g]

What is the capacity (volume) of each accumulator?

 

[ShaunCorbs]

Correct as this will give you a slight boost in pressure at your taps hence the chargers

 

[ShaunCorbs]

What is the capacity (volume) of each accumulator?

450l each

 

[Skiddaw]

What is the capacity (volume) of each accumulator?

900l total capacity per accumulator, so 450l of water each (I hope I have got that right)

 

[Skiddaw]

Correct as this will give you a slight boost in pressure at your taps hence the chargers

The system is great and this is the first problem we have ever had. Quite happily runs a house with a couple of showers, dishwasher, washing machine etc all at the same time with good pressure on all outlets at the same time.

It is annoying the only thing which has been changed is the charger and suddenly the problem has happened.

So I will empty and reset the pressure amounts and try again. Probably in the morning now as takes a while to empty even one. Thank you keep the info coming, it is very much appreciated. I will report back with how I get on.

 

[John.g]

If you set the pre charge pressure to the mains pressure of 1.5bar and pump the accumulator to 2.8 bar then the (each) accumulator will accumulate 154 litres of water and will release the same in falling from 2.8 bar to 1.5 bar.
IF it requires 3 hours to charge each accumulator the the charging pump is only pumping 0.85 LPM, something certainly not right there.

 

[Skiddaw]

If you set the pre charge pressure to the mains pressure of 1.5bar and pump the accumulator to 2.8 bar then the (each) accumulator will accumulate 154 litres of water and will release the same in falling from 2.8 bar to 1.5 bar.
IF it requires 3 hours to charge each accumulator the the charging pump is only pumping 0.85 LPM, something certainly not right there

 

[Skiddaw]

It is not normally 3 hours, before the charger change both will fill from empty in about 15 mins. The 3 hours I mentioned was how long the charger will run before auto switching off. We only let it run after the charger had been replaced to see if both accumulators would fill, we contacted the plumber (who had left once the charger had been replaced) when it was quickly clear only one vessel was filling, they normally both fill at the same time. He said to leave it for longer to see if the other one filled, hence leaving it until the charger hit its maximum run time before shutting off.

 

[John.g]

15 minutes seems OK, = ~ 10/15 LPM. You will get a accumulated vol of 220 litres with pre charge pressure of 0.95 bar and the same released in falling to 0.95 bar but only 121 litres to 1.5 bar, still not bad.
When you say one accumulator is not filling do you mean the pressure is not rising to 2.7/2.9 bar?, is it rising at all?.

 

[Skiddaw]

15 minutes seems OK, = ~ 10/15 LPM. You will get a accumulated vol of 220 litres with pre charge pressure of 0.95 bar and the same released in falling to 0.95 bar but only 121 litres to 1.5 bar, still not bad.
When you say one accumulator is not filling do you mean the pressure is not rising to 2.7/2.9 bar?, is it rising at all?.

No water is going into one of the accumulators at all, well as much as I can ascertain it isn't, it remains hollow sounding when empty compared to the other one which doesn't, it is the way we have always known they are full. TWS (now Stuart Turner) always said it is the best way to know they are full!

 

[John.g]

Actually you said it only takes 15 mins to fill both together so the charger is pumping ~ 25 LPM.

If no pressure gauge anywhere its quite easy to see if its charging or not, just check the pressure at the air end (assuming you have a pressure gauge) it will be exactly the same as the water side.