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Matt0029

Gas Engineer
Oct 6, 2017
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Heating Engineer (Has GSR)
Has anyone worked to the txn150pterp kingspan unvented cylinders? They have an internal expansion bubble like the megaflows I believe. To repressurise the internal expansion bubble am I correct in saying turn the power off to the immersion/heating turn water off. Then open lowest tap to drain and open the temperature relief valve to drain too. Once empty refill? Can any one explain how this recharges the air bubble?
 
Hello mate, I think I may have repressurised one before, it will be the same as the megaflo.

There are baffles inside the cylinder and when you half drain it down and refill it, you trap a bubble near the top which acts just like an expansion vessel. Over time they can lose their bubble and need the air needs to be trapped again. It usually only needs to be drained halfway or to the servicing drain off point.

I've attached a pic of another make's cylinder but the principle will be the same.
 

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