O-Ring size for Watts LF70A?

[mrbob]

Can someone here tell me the size of the o-ring that I need for a leaky Watts LF70A tempering valve? I know that I can buy a new valve or a repair kit, but it seems that I just need a new o-ring. Water is slowly dripping out of the knob.
Thank you.

 

[arctic bill]

I would just open it up and look at the size. Then take it to a plumbing store.
I bought many years ago a O-ring kit , that has saved me hours of screwing around.

 

[mrbob]

I'm still confused. An amazon Q&A plumber said that there is a 106 o-ring on the stem and a 116 o-ring on the nut. I called Watts and they said that, from looking at the literature, there is no o-ring on the stem. Also, there is no stem in the repair kit, so they said that if the stem leaks, the whole valve needs to be replaced.

I was hoping to hear from someone who is hands-on familiar with the LF70A to hear their perspective on a leak at the stem.