Your meter will read average DC or rms.
If it reads average DC then the average will be peak/(2√2) =115V

If you connect between S2 and mains live, you will also get a half-wave signal, the same as if you connect between S2 and neutral.
I still think that the opto pin1 should go to neutral.

Yes, meters read average or RMS, most likely I am confused, I was going with your simulation result of -325V peak.
I am tempted to try Pin 1 to neutral...

 

Yes, meters read average or RMS, most likely I am confused, I was going with your simulation result of -325V peak.
I am tempted to try Pin 1 to neutral...

-325V peak on a half-wave rectified waveform is -115V average.

 

-325V peak on a half-wave rectified waveform is -115V average.

Sorry, missed the half-wave - told you I was confused

 

Sorry, missed the half-wave - told you I was confused

It is counterintuitive how you can get a half-wave rectified waveform from a full-wave bridge rectifier!

 

I still think that the opto pin1 should go to neutral.

@Ian0 You are right, I just connected pin1 of both optos to neutral and the issue is no longer. Thank you Ian, if it comes to upgrades, I will implement that change.

Thank you all for your input and help.

 

First thing that came to my mind is that your electrical outlet may possibly have neutral and line reversed.

First - glad to hear you resolved your issue.
Second - I only mentioned neutral and line being reversed because I rented a house that was old Knob & Tube wiring. The home owner (not a licensed electrician) did some upgrades to the electrical system, and there were several places he guessed at which was line and which was neutral. This resulted in a number of electrical shocks I experienced. His name was called out on many occasions. But the biggest reason why I brought it up was because I had a power supply (with ground) that was protected by a fuse. AS SOON AS I plugged it in the fuse blew. Replacing the fuse and plugging it in resulted in the same exact problem. However, when plugged into a different outlet the fuse did not blow.

After having read all the other comments I see that my point was not germane to the discussion. But for anyone who has ever experienced anything like what I did - in my case it was reversed polarity and ground that brought about the issue.

Again, I'm glad your problem has been resolved.

 

One learns to cope with live and neutral reversed when one deals with the Germans and their reversible plugs!

 

@Tonyr1084 Fully understand what you mean, a seriously dangerous situation, and of course a valid point. Thank you.

@Ian0 I was wondering where that was going! Many countries have reversible plugs, they like to live dangerously!