Rad valves with O-rings

[smallsteve]

Some RAD valves come with O-rings, whereas the majority do not and I just wonder if one is better than the other or whether it makes no difference whatsoever?
Reason I ask the question is that I have spent ages looking at valves and have settled on the ones in the link, but I’ve never used valves before with O-rings and so before I hit the buy button I just want to check with you guys: Valves

TIA

 

[steadyon]

1. It doesn't really make any difference.
2. If you use the ones with O rings, the radiator surface where the O rings sit must be smooth. Very often they aren't.
3. There's nothing wrong with the ordinary sort. Its just a matter of wrapping sufficient PTFE tape around the threads to make a leak free fit.
4. The number of turns of PTFE depends on how tight the threads are without anything. Fairly tight, and you might start with 8 wraps, fairly loose and start with 15 to 20. In proportion for a different fit.
5. There are other sealing methods:
5a. Loctite 55 cord - allows for some (max 1/2 turn) backing off. Not needed for radiator tails.
5b. Loctite 577 or Flomasta Pipe Seal. Liquid sealant. Very easy to use, gives a good seal, expensive.

 

[smallsteve]

1. It doesn't really make any difference.
2. If you use the ones with O rings, the radiator surface where the O rings sit must be smooth. Very often they aren't.
3. There's nothing wrong with the ordinary sort. Its just a matter of wrapping sufficient PTFE tape around the threads to make a leak free fit.
4. The number of turns of PTFE depends on how tight the threads are without anything. Fairly tight, and you might start with 8 wraps, fairly loose and start with 15 to 20. In proportion for a different fit.
5. There are other sealing methods:
5a. Loctite 55 cord - allows for some (max 1/2 turn) backing off. Not needed for radiator tails.
5b. Loctite 577 or Flomasta Pipe Seal. Liquid sealant. Very easy to use, gives a good seal, expensive.

Appreciate the detailed response.

When using ptfe on rad valves, is it worth adding a dab of something like Hawk White, or is it unnecessary or maybe a pain if you ever have to remove the valve again? I already have Hawk White, as well as hemp, but not used either yet.

 

[Ben-gee]

Not necessary.

 

[Ben-gee]

Not necessary.