Saunier Duval Thema F35e - Question re Expanssion Vessel

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Hello All

1st time poster

Question re the above boiler, my pressure keeps dropping, looks like the boiler is discharging via the blow off.

I emptied the boiler via the blow off. Charged the expanssion vessel to 1 Bar, & pressurised the system to 1.5 Bar (Thing is, the minute i took the pump off of the expanssion vessel, air came blasting out the inlet, until i screwed the dust cap back on)

Is this because my expanssion vessel is cream crackered, or is it possible for there to be water in the expanssion vessel, & that's causing the air to blow out, when i take the pump off the inlet valve?

I've managed to get the system up & running by doing this, but i fear it's only a temporary measure, as the blow off outside is still discharging water.

Any ideas?

 

[Gasguru]

Do you mean ALL the air discharges our of the vessel valve once you remove the pump? If so the valve core may be faulty (highly unusual though). If you talk to a tyre fitting garage nicely you could buy a standard tyre valve and ask them to buy/borrow the removal tool. If there's sufficient room it's then very easy to replace the valve inards.

Typical core removal tool http://en.wikipedia.org/wiki/Image:Kaperka.jpg

 

[encblue]

Thanks for your reply Gasguru

No, once i remove the pump, it would fall from say 1 bar to 0.6 bar or there abouts. Would this be caused by water in the Exp Ves?

 

[Gasguru]

It's normal to loose a very small amount of air just as in inflating a car tyre. I use a standard old type cycle pump...these "release" less air than some of the car tyre foot pumps.

When you inflated the vessel you did make sure the system had zero pressure in it all the time ie leave set the safety in the open posistion. As you inflate the vessel with air water will will be expelled back into the heating system.

You may have to replace the safety valve since they have a tendancy not to reseal.