How does a Vaillant plate heat exchanger work?

[mickspencer]

Hi everybody,

We have a Vaillant TurboMax Plus 824e, the plate heat exchanger is model is 065123, as listed here, which has been replaced by model 065131

http://www.247boilerparts.co.uk/vai...eat-exchanger-part-no065123-065131-1426-p.asp

I have found some instructions on how to swap this out myself, although I just want to understand how the exchanger works. As when I turn the hot water on, I can feel that on three of the pipes leading in\out have hot water, and only one has cold water feeding in. This leads me to believe that the cold water feeding in is being heated by hot water heated elsewhere?

If this is the case I want to make sure I am draining all the correct areas as I thought I only needed to drain the primary with the two screws on the left and right underneath, after isolating the cold water and draining the hot water taps.

Is this all the drainage that is required, is it only water from these feeds that enter the heat exchanger?

Thanks in advance, all help appreciated!

Mick

 

[45yearsagasman]

To remove a plate heat exch, the cold feed must be closed and the boiler should be drained.