About 10 feet!
Are you mad?

Could you please give a serious response if you have experience with this issue?

Edited. I’ll let someone with experience of this respond.

@sgalloway

30cm is a good distance ime, though when I owned a beam I had it mounted about 22 cm and it was fine. This depends on your fireplace though, so ymmv. 

Moderator Note: Modified in accordance with the Community Code of Conduct.

The Arc’s operating temperature is listed as between 32°F to 104°F (0°C to 40°C) - so I would put a thermometer where you plan to place the Arc and leave it there with the gas fire on for a few hours and just ensure the temperature (overall) is not going to reach the limit stated, bearing in mind that the Arc itself is going to get warm too whilst playing for some hours, so measure its temperature aswell with a laser thermometer and add the temperatures together. I would aim for an overall temperature of no more than 30°C to keep things well within the limits stated.

That said, I personally would not want to use this type of setup myself as it sounds a little unsafe to me and I think a good many people might advise against such a placement. Same goes for the TV too.

My Arc has been mounted 150mm above the gas fire place. No issues 4 years on

Hi @sgalloway, on a related note you’ll need 4 inches between the top of your Arc and the bottom of your TV for proper Atmos. 

When measuring the temperature at the proposed location, mount the thermometer in a box. The box should be the same color and cross section as the ARC.

Generally, I think that gas fireplaces would be safe because they are enclosed. If the wall immediately above the fireplace is very warm or obviously discolored, abandon the project and don’t waste your time.

As suggested above, take your measurements in an enclosure as you need to account for both radiant and convection heating.

I wouldn’t rule out a mantle, there are some fantastic glass designs that are nearly invisible and that would deflect a lot of the convection heat. Maybe use mirrored glass and beat the radiant too.