Balanced flue problem. Can I do away with the air intake flue?

[Peter B]

i have an old CH Camry boiler which is still sound as a pound. It's situated in a lean-to building/outhouse that also houses our dishwasher and washing machine,but not much else. The lean-to is well ventilated, only having a corrugated Perspex roof.
The flues (balanced) are stainless steel, both for air intake and exhaust. However, the exhaust flue's spot welds have all but disappeared and I was wondering if I could use the air intake flue as a replacement for the exhaust and just leave the air intake flue shorter, to take in air from the room which has an external door to our kitchen (usually closed).
The air intake flue is as good as new and it would be great if anyone skilled on here could advise.
Thanks in advance.

 

[bernardgreen]

The flues (balanced)

The word balanced is the clue. The air intake and the exhaust have to be located where the air pressure is the same on both of them. If one is indoors and the other one outdoors then the air pressures will not be the same and the volume of air supplied to the burning gas will not be correct.

So no you cannot modify the flue and air intake like that.

NOTE that I am NOT a gassafe registered person, my opinion is based on basic knowledge and common sense

 

[Doggit]

This old post may explain it a little clearer

The balanced flue terminal has the flue outlet and air inlet in close proximity, so that any draughts or gusts of wind affect both equally and cancel out in the appliance. In this way the burner flame and even pilot lights are not affected.

Because balanced flues are only powered by natural draught (the draught created by the hot flue gases), they must be kept quite short, usually just sufficiently long to pass through the external wall against which the appliance must be installed.

But from the way you're describing the boiler, it almost sound as though you have a separate intake and exhaust flue, however, as BG suggests, leave well alone, and replace the exhaust flue, and stay safe (even if you do the replacement yourself), and stay legal.