hello there iv just turned my 600w mh on to try and calibrate the fan controller i built, however it got hot in there in ten minutes to about 29c.
the fan kicked in ok to full power and it stayed on , . my thermometer and thermostat are in the same position on opposite walls. they are at about half way up the walls, in direct light, theres no shade in there (no plants yet either). i guess they are in the wrong place could anyone give me some advice on where to put them , once i got the temps/fan running stable, i can start trying to calibrate the heating system, ill do it on one of these cold autumn nights, then im ready to grow! i have looked on forum but can only find heater/ fan placement advice
thanks in advance.
im sick o this wet street weed) headache headache

I just stick mine on the floor (out of the direct light too).

If the light shines on it, can give you false reading.

i'd put them just above the level of the reflector where you can see the beam of light hit the wall, just above so it's not in the beam, and get a fan blowing air onto it/them

I use several and have them all over the place. The critical ones of course are the ones at canopy height, but I find that knowing what the temperatures all over the grow room is helpful. I now use small oscillating fans under my trays (above a concrete floor) to keep cold air from settling. A major goal of oscillating fans is to create a homogenous temperature gradient through out your grow room.

thanks smokey,scraglor randalizer

ill go with scraglor, cos im in the shed and the passive in is at floor level, at least til iv got some greenery to shade things, i will do it tommorrow night, (try and settle fans/temps) thanks again,

also my thermometer from greens seems faulty , the humidty reading is --, it used to work. ? anyone know

out of range quite possibly, mine does the same when saturated or below 20 rh

Thanks sstoker. One reason why I have several measuring devices is that if one goes bad, it's easy to compare with all the other readings.

eta: a new battery might help.

must been out of range its ok now, probly all my sweating /workin in there. still not done. just tying up loose ends finishing mylar , couple more weeks i reckon , realisticly. (growroom, comes after , family, work, and revamping bathroom unfortunately.)