Plate Heat Exchanger Grant Vortex Pro Internal Combi 26

[CoreStorage]

I replaced the plate heat exchanger 18 months ago and despite the supplied fibre washers and good cleaning of pipe faces, the top supply (mains pressure) joint has always weeped a little, despite re-tightening. With the heat, it quickly evaporates but now the build up of calcium is making me wonder if it will cause a failure of the heat exchanger, just like the previous one. I don't really want to drain down the system and remove it, I just want to clean and re seal the joint. Can someone suggest the best approach, do I use more than one fibre washer to increase thickness, some other type of washer, a sealant (what sort) should I wire brush the surfaces clean, or use emery paper, or even a file (I think probably not) ?
Even if I am advised to remove the whole heat exchanger to clean all the surfaces, I'd still like to know what washers/ sealant to use.
Thank you for any advice. Andrew.

 

[Exedon]

We tend to throw the fibre washers and use rubber ones (having first made sure mating surfaces are clean) I use cleaning tape because it's always in van.
If your getting hardness building up you really should consider some sort of water treatment.

 

[CoreStorage]

Thank you for your very helpful reply, I shall follow your recommendations. I didn't know rubber washers were used, and presumably they don't need to be done up so tight. And thanks for making me think about water softening, there is presently just a Sentinel Electrolytic Scale Inhibitor which is at least 5 years old, and probably not really up to the task in the first place. I will put something better there.
Thank you again, Andrew

 

[oilhead]

I think your Sentinel scale inhibitor is fitted in the primary circuit and protecting the boiller and pipework. Exedon is recommending treatment of the mains feed into the DHW heat exchanger.

 

[CoreStorage]

Thank you Oilhead, it is actually in the 15mm mains cold feed into the heat exchanger, that has the Sentinel device in. I have an ADEY Magnaclean and inhibitor in the primary circuit. I am hearing that electrolytic inhibitors are not much good, and my experience confirms that.
I am considering a Cisternmeister with Siliphos balls as a lower cost alternative to a full blown water softener. I read that not everyone is happy with the chemicals / mirerals /ions that they introduce, but since it is not the whole property that I wish to soften, just the DHW supply, I think it should be fine.
Thanks for your interest.