Is my EV faulty or not?

[geoffcc]

Hi got a Worcester 30si compact and found the pressure on the EV was low. Changed the Schrader valve and pumped some air in (having trouble measuring the pressure with my car gauge as by time I get it on half the pressure has been lost). I am getting a plumber to come and pressurise the EV properly and at the moment the system is sitting at 1 bar cold and 2 bar hot. When I release all the pressure from the schrader valve no water comes out. However, still wondering if it is possible that the EV diaphragm has gone and that I am just pressurising the vessel itself? What I mean is that 30si compact EV is oblong and sits vertical with the water feed at the bottom and the schrader valve at the top. If the diaphragm had gone there could still be air at the top and water at the bottom with the whole vessel acting as an EV? How would I know if this was the case? My other question that I have searched for, but never found the answer to is what if the air pressure in the EV is set too high? How would that affect the pressure in the system?

 

[ShaunCorbs]

Did you drain the heating system when you checked the pressure on the vessel?

 

[geoffcc]

Did you drain the heating system when you checked the pressure on the vessel?

No. Just put enough pressure in the EV to stop the pressure swings. Now worried if I have put too much in. I know to do it properly you need zero pressure in the system - and I think you need the system open (e.g. a radiator bleed valve open - whilst pumping up the EV and measuring the pressure to around 1 bar. Not got any good way to measure the EV pressure accurately, hence getting a plumber in to set it up properly. The system pressure is staying in the green (just)

 

[SJB060685]

As Shaun says, the pressure in the system (water) needs to drop before you can charge and check the diaphragm pressure, otherwise you get false readings and problems. If the diaphragm had ruptured then one would expect the air to escape into the system.
If the vessel precharge was too high as you ask then the water pressure would have to increase to said pressure through heating before the diaphragm accepts expansion, this can be noticed by a higher final system pressure

 

[John.g]

Hi got a Worcester 30si compact and found the pressure on the EV was low. Changed the Schrader valve and pumped some air in (having trouble measuring the pressure with my car gauge as by time I get it on half the pressure has been lost). I am getting a plumber to come and pressurise the EV properly and at the moment the system is sitting at 1 bar cold and 2 bar hot. When I release all the pressure from the schrader valve no water comes out. However, still wondering if it is possible that the EV diaphragm has gone and that I am just pressurising the vessel itself? What I mean is that 30si compact EV is oblong and sits vertical with the water feed at the bottom and the schrader valve at the top. If the diaphragm had gone there could still be air at the top and water at the bottom with the whole vessel acting as an EV? How would I know if this was the case? My other question that I have searched for, but never found the answer to is what if the air pressure in the EV is set too high? How would that affect the pressure in the system?

I doubt if the diaphragm is ruptured.
The EV will eventually fill with water if the diaphragm is gone and the PRV will lift each time the system heats up, same effect as having no EV.
It can be checked for rupture before re pressurizing by releasing all the air via the schrader valve and then ensuring ~ 1 bar on the water side, water will then come out of the valve if diaphragm ruptured.