Radiant heat temperature questions

Rookie123

I just fired up my boiler a couple of days ago and am wondering why my temp gauges on my control panel read 120 degrees while the temperature gauge on my supply manifold reads 150 and the temperature gauge on my return manifold reads 130ish?? There is a sticker on my panel that says "Max panel temp 150 degrees." Do I go by the panel temperature gauges or by one of my manifold temps? Learning as I go.... thanks for any help!