Customer called us out due to suspecting a gas leak. Performed gas leak inspection. Checked all fittings with combustible leak detector for all 3 dryers. Used Spray leak detector on every fitting for leaks. Found one gas flex on the single dryer was loose. Tightened it. No visible sign of any leak. Customer will leave gas on over night. If any further issue detected, we will return. No signs of any visible leaks.