Replacing convector help

bdwild

Hi All,
Geez I'm addicted to this site! More to come improving my system but for now I'm fixing some leaks. First up is replacing a leaking convector. The unit should be here tomorrow, and here's a photo of the replacement valve. I'm good on the threaded parts but
My question: Do I need to seal the mating faces of A and B with anything, or just tightening seals the deal?

Jamie Hall

That's a union. The seal is between the very smooth left hand ring of part A and a corresponding female ring inside the valve itself. The big nut -- part B -- serves to hold the whole thing together. Don't forget to put part B on the nipple into the radiator before you thread part A onto the nipple!

The threads from part A onto the nipple should have sealant, like any other threaded plumbing joint. Use your favourite. I'd probably use Blue Monster, but that's me. The mating surfaces of the union -- part A into the valve -- do not need any sealant, and shouldn't have any. However, you may find that to get it to take up snug it helps to rock the radiator slightly back and forth.

The assembly will not compensate for misalignment -- get things straight before you begin.

The final assembly shouldn't leak (of course) but you needn't be a gorilla on part B -- good and snug, yes, but don't overdo it.

EdTheHeaterMan

@Jamie Hall Nailed It!


Here is a picture. The inside here means pipe dope on the outside of the pipe nipple as JH indicated

bdwild

Thanks much @Jamie Hall and @EdTheHeaterMan, for all the important tips! Yes, got some Blue Monster and yeah, I've gone over that "dont be leaving the part B aside" about 10 times now, LOL!
Do you guys teflon tape and dope, or just dope?
Appreciate your help!

nicholas bonham-carter

Don't forget a little dish-washing liquid will help to mate the union surfaces, as you are rocking them back and forth, while tightening the union nut.
This is not for sealing Per Se, but for enabling the union faces to slide properly together, as they are tightened, and rocked.--NBC

bdwild

Thanks NBC - will do!

bdwild

Another question on these valves if you would... I plan to replace three that are leaking - two are 1" and one is 1 1/4". As I hope you can see in the photos (all handles are turned to full open), the two 1" valves open all the way to where the inner plate seats at top of bonnet.
The 1 1/4 does not. It's at least a 1/4" if not 3/8 away from seating.
Is this "fully open"? Did I get a faulty valve?