External expansion vessel best locations

[icarusbop]

Hello:

The expansion vessel on my central heating is faulty - the water pressure is all over the place when heating and it keeps opening the pressure release valve. I went to re-charge the expansion vessel but water came out of the air valve, indicating the bladder has failed.

The boiler is in a difficult to reach location and needs removing from the wall to replace the vessel, not only can I not do this, but I estimate a bit of collateral damage to the surrounding kitchen space due to the tight git and location of the boiler.

There fore I am hoping to simply ignore the failed unit and add an external expansion vessel to the CH system to fix the issue, there is no-where convenient next to the boiler to site the second unit, so am hoping I can pout it somewhere else - under the stairs where both the flow and return pipes run would be really easy and convenient and out of sight.

Some advice says the should be near to the boiler on the return, but this is really not convenient - is my suggested location OK? (approx halfway around the CH circuit)

Thanks - IcarusBop

 

[Dan Robinson]

It need to be near to the suction side of the pump.

 

[The831Bunny]

Hello:

The expansion vessel on my central heating is faulty - the water pressure is all over the place when heating and it keeps opening the pressure release valve. I went to re-charge the expansion vessel but water came out of the air valve, indicating the bladder has failed.

The boiler is in a difficult to reach location and needs removing from the wall to replace the vessel, not only can I not do this, but I estimate a bit of collateral damage to the surrounding kitchen space due to the tight git and location of the boiler.

There fore I am hoping to simply ignore the failed unit and add an external expansion vessel to the CH system to fix the issue, there is no-where convenient next to the boiler to site the second unit, so am hoping I can pout it somewhere else - under the stairs where both the flow and return pipes run would be really easy and convenient and out of sight.

Some advice says the should be near to the boiler on the return, but this is really not convenient - is my suggested location OK? (approx halfway around the CH circuit)

Thanks - IcarusBop

If you pressurise the existing expansion vessel the diaphragm will probably seal along the welt. Fair enough if you can hear the air pushing through when you pump it up, but its usually worth a try.

Most expansion vessels will pass water to the air side if flat, resulting at water at the Schrader.

 

[ianmcd]

far too many expansion vessels get changed when they could be re-charged, lots of posts on how to do it but you MUST follow all the steps you can not half do it

 

[gasbanni]

Yes you can bob it under the stairs, Alternatively drain down and dont bleed a rad fully in a room that doesn't matter or need full heating ....That will act as a temporary expansion vessel.


Ps if water comes out if the valve you're right it's goosed !

 

[ianmcd]

Yes you can bob it under the stairs, Alternatively drain down and dont bleed a rad fully in a room that doesn't matter or need full heating ....That will act as a temporary expansion vessel.


Ps if water comes out if the valve you're right it's goosed !

sorry dont agree

 

[AGAS]

Ps if water comes out if the valve you're right it's goosed !

what about moisture can collect within the vessel and also water coming out doesn't always mean its fooked

edit fooking auto correct

 

[icarusbop]

Hello:

Thanks for the help so far.
I've checked the vessel more - lots of water came out of it, not just a bit, so I don't think it's moisture.
I did try to recharge it according to the guide from this site, but could hear air escaping into the system and the pump auto vent started venting, so I think it's definitely broken.
In the meantime I let air into a non-essential radiator (about 1/3rd) and re-pressurised the system, I now get heating without the pressure going wild and the pressure release vale opening - so I'm not losing my water anymore!

Back to the original question - I have conflicting answers regarding putting my second vessel under the stairs - this would be about halfway round the system on the return.
From my limited understanding, the only downside I can see of it being here is that it will fill with hot water rather than cool water - reducing the efficiency of the system a little - but my tool cupboard will be nice and warm...

What other reasons are there for not putting it in this location?

Thanks
IcarusBop

 

[gasbanni]

what about moisture can collect within the vessel and also water coming out doesn't always mean its fooked

edit fooking auto correct

You really think if a load of water comes out of the valve it's not goosed ? Really !

 

[gasbanni]

sorry dont agree

I'm all ears or eyes .....so the diaphragms not split / pin holed when water comers out of the schraeider valve ......pray tell, where the water coming from ?

Collecting collecting from soddin where ?????

 

[Dan Robinson]

Think it depends on the volume. Recently we've had a couple of dead vessels, but no water (or air). It all depends where the failure point is.

Think it affects rectangular vessels more than round.

 

[gasbanni]

what about moisture can collect within the vessel and also water coming out doesn't always mean its fooked

edit fooking auto correct

It's a sealed vessel apart from possibly a little water from condensation where the hell is the water collecting from !!!!!!!

 

[gasbanni]

Charge lost diaphragm ok .....nothing comes out. Recharge no problem.

Water comes out diaphragm punctured pin holded ...goosed..... Dan your as bad as me........get to bed.
Nightmare to put on cc later in the week.......

 

[The831Bunny]

Charge lost diaphragm ok .....nothing comes out. Recharge no problem.

Water comes out diaphragm punctured pin holded ...goosed..... Dan your as bad as me........get to bed.
Nightmare to put on cc later in the week.......

It’s true in some cases, fairly obvious as well!

But I have seen plenty of rectangular vessels (read Zilmet) with water at the Schrader valve and they pump up ok. Seems like the diaphragm loses the tension at the welt or seam when flat and water passes around. When you pressurise it, it tightens up and seals again. Just my theory though...

 

[gasbanni]

It’s true in some cases, fairly obvious as well!

But I have seen plenty of rectangular vessels (read Zilmet) with water at the Schrader valve and they pump up ok. Seems like the diaphragm loses the tension at the welt or seam when flat and water passes around. When you pressurise it, it tightens up and seals again. Just my theory though...

You can pump up a failed vessel absolutely, forcing air and it will work .......but if doesn't mean the vessel hasn't failed. If water is coming through the valve it's failed...... seal, diaphragm it doesn't matter which it's failed. End of.

I've pumped up failed vessels many a time to get the heating back on.
If you've got water on the dry side of the vessel it's Damn well failed.
How else does water get there ??? Should it get there ? NO !