ideal isar he24 pressure rises when c h on

[dalkld68]

hi i have an ideal boiler he24 which i have been told needs a new expansion vessel.the problem is as follows
when ch on pressure rises to 3 bar and sometimes a little over.this is with the burner on full- plumber said e v needed replacing .i have checked it and no water comes out i thought this had to happen if it was knackered.
anyway i have re charged it to 0.75 and the pressure still goes up.
any suggestions would be much appreciated.
thanks

 

[swbjackson]

When you recharge the vessel it has to be done against atmospheric pressure. You need to isolate the boiler and open the drain off on it and leave it open while you re pressurise the vessel.

 

[dalkld68]

sorry i dont really understand that..women ay!!do you mean drain the pressure down to 0 then do it??

 

[gas4you]

Yes, but also leave the drain off under the boiler open whilst pressurising it.

Although 0.7-0.8 is the norm, I tend to pressurise to about 1 Bar, then by the time the pump 'nozzle' has been removed and some air has escaped, it will probably be around the 0.7-0.8 mark.

As a side point, as this requires the combustion chamber opening and the fan being removed, which entails a gas connection being undone, only a RGI should be doing this

 

[dalkld68]

would i be right in saying that if no water comes out of the vessel then it is not totally had it as the man has told me. i will call them back if this is right

 

[gas4you]

Yes you are correct. If it is knackered then water will come out usually.

Today though I was at a 105e instant, EV wouldn't keep pressure, no water but the valve on it was sticking open slighlty and letting the pressure out very slowly

 

[dalkld68]

did you fix it?? it was beginning to cross my minfd if this is whats up with mine.i have read and tried to understand so many bits of info on this but i cant fully understand it.i thought it was a case of get your foot pump and pump it up...this is obviously not the right way to do it! hope i havent done any harm

 

[gas4you]

Only temporarily till a new one turns up

I doubt you have done any damage to the EV.

 

[dalkld68]

you mentioned combustion chamber removal and something to do with the fan,why would these need to be removed i can fit my hand in to get to the e v .think i will leave it alone though

 

[dalkld68]

thankyou anyway

 

[gas4you]

you mentioned combustion chamber removal and something to do with the fan,why would these need to be removed i can fit my hand in to get to the e v .think i will leave it alone though

The air valve on the EV on an Isar is behind the fan assembly, in the sealed cumbustion chamber

Where are you putting your hand?

 

[dalkld68]

i can get my hand in through a gap ,its red isnt it ex vessel? bit like my face ha ha.it has a black cap on it like a car tyre. its the same place my plumber was poking about.i only got small hands. its an ideal isar he24

 

[gas4you]

New one on me All the Isar HE's that I have ever seen have the black cap on the red EV poking through about a 1" hole behind the fan.

I can't picture how anyone can get a hand on to this, however small they are if the boiler is in one piece, from the outside