TPW problem

[Reklaw]

Hello all, I hope this is in the right forum although I am not exactly a beginner, I am new to TPW washes.
Just before Xmas I ran a Turbo through my still, (a Nixon Stone type reflux) as I have done countless times, got the usual results and volume of product from a 20L wash, around 3L of 92% after cuts.
Then I read about TPW, I have been out of the scene for a while, gave it a shot with disappointing results. (25L wash @12%) The column settled down at 78c for a while but after drawing off about 1L the temp at the top of the column shot up to 90C. Jiggling with water flow and take off rate would bring it down slightly but the product was down to about 40% and dropping. Tried another wash using a different boiler and had the same result, nothing has changed within the column and I still get the same scenario.
Could it be that the TPW does not produce enough alcohol to stack the tall column enough to counter the pressure from the upward water vapour from the boiler. Not very scientific, I know, but I am lost as to why this is happening, I would rather stick with TPW than go back to Turbo.

[Doubleuj]

The Nixon stones are a pretty old type of still but I have heard of people running them here and I am assuming they would have been running a tpw or one of the other tried and proven recipes.
One thing to try is to strip a couple of washes and dilute them to 40% or less with water and re run them.
That way you’ll have a tpw that is 40% to start with.
Never re run anything above 40% abv though.

[wynnum1]

I put the fist 1 litre of the previous TPW run back into the next wash and that increases the alcohol content and that seems to help as the TPW has lower alcohol content.