Fitting New Valves

[novaf4]

I'm going to fit a new thermo valve and lockshield to my steel radiator. Both have the same type of fittings. I'm going to use the lockshield for this example.

In the photo below:

• 'A' screws into the radiator and has a tapered rubber washer/buffer.
  
• 'B' fits over the pipe and has an olive.
• 'C' is where both 'A' and 'B' parts join together.

Please can you advise me of the following:

1. I think I should attach the parts in the same sequence as their corresponding letter. Do you agree?
2. Should 'A' use PTFE tape even though it has a rubber washer/buffer? If so how many turns of the tape is recommended?
3. Should 'A' screw in all the way until the rubber washer/buffer bites?
4. Should 'B' use PTFE tape and if so how many turns of the tape is recommended?
5. Should 'C' use PTFE tape and if so how many turns of the tape is recommended?
6. Should the lockshield's open/closed valve be 'open' or 'closed' during the fitting process?
7. Finally, I have some new bleed valves that need fitting into the radiator. Should they be screwed in all the way in until their thread runs out? Should they use PTFE tape and if so how many turns of tape?

Is there anything else I should know / any tips?

Thanks.

 

[muggles]

1. Yes, correct
2. Depends on how well the radiator has been machined. Personally I'd cut the o-ring off and use Loctite 55 on the threads. Haven't used PTFE on metal threads for years. How much of either you use depends on how tight or loose the fitting is in the radiator. It's a bit of a matter of experience.
3. Depends on how you approach (2.)
4. No. The threads there are to hold the nut in place, they don't provide any sealing function. The olive does that.
5. No. See (4.)
6. Doesn't matter, either is ok. You can even have it half way.
7. Depends on what type they are. A photo would help

 

[novaf4]

Thanks for your recommendations and the Loctite 55 tip - I've just ordered some.

I think I'll use Loctite 55 as well as the rubber O ring, assuming that's acceptable.

I think I should have called them Air Vents instead of Bleed Valves. They are standard brass ones that most radiators have, like on this page:

https://www.toolstation.com/air-ven...MIluTFoeuM5QIVibTtCh0neQB-EAQYAyABEgKD0PD_BwE

 

[muggles]

If it's those specific ones then yes, L55 will be needed. Be aware though that most modern radiators are 1/2" tappings, and the vents you've linked to are 1/4"

 

[novaf4]

I wouldn't call it modern - it's a 60's rad. The link was just an example. The ones I have screw on fine.