Megaflow tank air bubble refill

[nodyland]

[FONT=&quot]Hi,[/FONT]

[FONT=&quot]I have looked on this site for the answer to this question but couldn't find it.[/FONT]

[FONT=&quot]My hot water pressure feels like its getting low.[/FONT]
[FONT=&quot]System is 7 years old and has never been touched apart from the normal yearly gas cert.[/FONT]

[FONT=&quot]All system is outside.[/FONT]

[FONT=&quot]I wondered if it was to do with internal air bubble. I understand to recharge air bubble is to shut off cold water combination valve and then open hot water tap in doors. After that then open PRV on tank.[/FONT]

[FONT=&quot]What I'm not sure of is when I shut of cold water combination valve and open hot water tap in doors there is no hot water flowing. I thought the idea was to open hot water tap to empty tank, but nothing.[/FONT]

[FONT=&quot]Anyway I went to PRV and opened that and it literally dripped to the tundish with gargling noises.[/FONT]

[FONT=&quot]Any ideas to help me understand / steer me to the correct path would be highly appreciated.[/FONT]

[FONT=&quot]Thank you[/FONT][FONT=&quot]

[/FONT]

 

[nodyland]

How my system is behaving at the moment: -

If I turn off cold water combination valve and run hot water tap in kitchen no water comes out. So I think to myself megaflow needs charging. Go to megaflow PRV turn it fully etc but nothing happens, no gurgling etc. Any ideas would be much appreciated.

 

[joni os]

With cold supply off, hot tap open and open PRV ,water should flow out of tank, air enter via PRV and when water level in cylinder is sufficiently low, air bubble is recharged.
If this doesn't happen, or PRV, afterwards, fails to close a G3 qualified plumber is necessary.

 

[rpm]

With cold supply off, hot tap open and open PRV ,water should flow out of tank, air enter via PRV and when water level in cylinder is sufficiently low, air bubble is recharged.
If this doesn't happen, or PRV, afterwards, fails to close a G3 qualified plumber is necessary.

joni, save your time mate nodyland has had all the intel from another forum today.

 

[nodyland]

Joni,

Many thanks for answer.

 

[nodyland]

rpm,

Problem with forums is there just full of unhelpful people like you. Meant to help people or whats the point of forums.

FYI. No i have not had question answered from another forum. In fact I have just had my question answered on this forum.

I am so so sooorrry for asking silly questions.

 

[rpm]

nodyland, in case of any misunderstanding........
Welcome to the forum, understand you are retired aero engineer with an interest in how things work which is good in the fact that you keep your mind active however please remember that members give up their free time to help people.
As I say welcome along.

 

[nodyland]

Thank you

 

[king of pipes]

Nodyland the advice from joni s is correct if you look on the side of the cylinder it gives directions on how to reset the floating baffle , turn all your hot taps on make sure you hold the PRV open , turn it 1/4 of a turn you will feel it lift off its seat water should then flow from the cylinder when this stops turn another 1/4 of a turn the PRV will reseat , turn off taps leaving kitchen tap half open you can then turn the valve back on to recharge the cylinder and set the baffle turn PRV as before and when water comes out reseat the valve , water should flow from the kitchen tap if this does not solve the problem the combination valve filter may be blocked , non return valve faulty or even the pressure reducing valve may be faulty as all are on the combination valve hope this helps

 

[Chalked]

Nodyland the advice from joni s is correct if you look on the side of the cylinder it gives directions on how to reset the floating baffle , turn all your hot taps on make sure you hold the PRV open , turn it 1/4 of a turn you will feel it lift off its seat water should then flow from the cylinder when this stops turn another 1/4 of a turn the PRV will reseat , turn off taps leaving kitchen tap half open you can then turn the valve back on to recharge the cylinder and set the baffle turn PRV as before and when water comes out reseat the valve , water should flow from the kitchen tap if this does not solve the problem the combination valve filter may be blocked , non return valve faulty or even the pressure reducing valve may be faulty as all are on the combination valve hope this helps

.
Hi King.
You don't open the prv until water comes out. You allow air in to let the floating baffle come down and return to its propper position.
This can sometimes take a few minutes with the prv open and water draining out off thT open tap.
P.s if you open a tap from a lower floor, this speeds the process.

 

[Chalked]

Just re read you post. You did actually say open the prv to drain the cyl.
Sorry.

 

[nodyland]

King of pipes.

Thank you for your help

 

[chris watkins]

Recharging the air bubble is unlikely to correct the lowering water pressure, it may help to store some additional pressure due to the water expansion so give the illusion but if you continue to run the taps & the pressure drops off this will be confirmed.

7 years seems to be the sort of life span for a big metal spring, time to call a plumber who holds a Part G ticket, a legal require to work on these systems, I am afraid.

PS it can take a lot longer than a couple of min's holding the T&P relief open to get all the water out & the air in. If your wrist can't take it you can always disconnect the hot outlet pipe from top of cylinder, much quicker.

 

[king of pipes]

Just re read you post. You did actually say open the prv to drain the cyl.
Sorry.

no worries just trying to make it easy for the guy

 

[zzzjim]

......

PS it can take a lot longer than a couple of min's holding the T&P relief open to get all the water out & the air in. If your wrist can't take it you can always disconnect the hot outlet pipe from top of cylinder, much quicker.

Don't over do getting water out , with taps too many floors down , as a lot of the cylinders strength is from the water pressing outward on it . Hence needing a Part-G guy to spot if things are not right !

 

[ShaunCorbs]

I'm sorry but get a G3 engy out most of the time the tp don't reseat so leak

 

[Dotty]

More Importantly, do not use the lowest tap. You will implode your cylinder.

Use the closest one.

Anything else you need a G3 for so here endeth the thread.