Nitrile or Viton o-rings for heat exchanger?

[Keith-i]

In actual fact neither material is particularly suitable for immersion in hot water, with Viton being the least suitable of the two.

Thats interesting thanks. I hadn’t come across any reference to hot water compatibility. EPDM doesn’t appear to be suitable for mineral oil contact though whereas my intercooler certainly gets a bit of oil mist in it. Unless you think Viton is totally unsuitable I shall run with what I’ve bought for the time being.

 

[vyv_cox]

Viton / FKM vs Nitrile: Which material is right for your application?

The o rings in my Beta heat exchanger are nitrile which is slighty more resistant to salt water with viton being more chemically resistant but I think the bottom line is that either will be absolutely fine.

The other property for which nitrile is the better choice is compression set. Viton may tend to leak after a time, particularly at elevated temperatures.

 

[Scarron]

You are correct Vyv, however this application is as I understand it a marine heat exchanger where the seal is exposed to a a hot glycol/water solution and/or hot salt water therefore hydrocarbon resistance is of minimal importance.

EPDM is the correct material in this application which is why all vehicle heater hoses are EP lined.

Afraid for the OP it’s a bit late as he has now sourced some replacement O-rings. They will work fine, but not for as long as they might as the material will prematurely age harden and allow leakage. On the bright side one should strip and clean heat exchangers every two to three years anyway..

 

[Scarron]

Apologies, missed the oil mist.. Silicone it is then, good with heat, water and oil.

 

[Keith-i]

Apologies, missed the oil mist.. Silicone it is then, good with heat, water and oil.

Thanks for the additional info Scarron. I shall have a chat with the supplier tomorrow to see if I can amend my order. I need o-rings for the main heat exchanger (coolant/sea water) where I presume EPDM might be best. For the intercooler (sea water/air -with slight oil mist) it looks like I should be aiming for silicone.