A mate recently bought thew Ziggy portable which I have and recommended he get over the Baby Q.
He rang the other day with an issue where he said it just wasn't get hot enough to roast a lamb loin and wondered if I could help work it out. I thought maybe a gas flow issue due to his regulator or something similar so I suggested he bring the Ziggy over to me with all the gas lines and bottle so we could test them side by side with mine.
As soon as he lit it up and I saw the size of the flame, I knew it wasn't a gas flow issue, in fact his flame was slightly bigger then mine. So I figured it must be an issue with his thermometer. When we let both Ziggies run for 10-15 minutes, mine was reading over 250c and approaching the red zone of 300c on the dial. His was still under 180 !
I put my Maverick pit probe on his grill and sat it on a small bit of foil so it wasn't getting direct heat from the burners. It showed about 240c !
So we swapped thermometers, let them cool for a bit and started again. Sure enough, doing the same test mine was now showing 180c and his was over 250.
The interesting thing was that the Maverick didn't agree with either thermometer reading. It was lower on mine by quite a way and higher on his by a similar margin, basically in the middle of both readings. I also hit the grill with an infra red temp probe and that was showing very little difference between each grill.
The conclusion. DON'T TRUST The ZIGGY DOME THERMOMETER.