High-speed hand dryer common failures and repair methods

High-speed hand dryer, generally we are often used in the bathroom, used to wash hands after drying the moisture on the hands of an electrical appliance. Occasionally there is no hot air, only the phenomenon of cold air, if you encounter these failures, how to solve it? The following is an introduction to the hand dryer common failures and overhaul methods.

Hand dryer common failures and overhaul methods

Fault phenomenon 1: hand into the hot air outlet, no hot air blowing out, only cold air blowing out.

Analysis and maintenance: cold air blowing out, that the blower motor is powered to work, infrared detection and control circuit is normal. Only cold air, the heater is broken or loose wiring. Upon inspection, the heater wiring is loose. Reconnect, there is hot air blowing out, troubleshooting.

Fault phenomenon 2: after the power. Hands have not been placed on the hot air outlet. Hot air is out of control blowing.

Analysis and maintenance: after checking, silicon controlled no breakdown phenomenon, suspected of photocoupler ③, ④ foot internal photosensitive tube leakage breakdown. After replacing the photocoupler, the work returned to normal, the fault is eliminated.

Fault phenomenon 3: hand into the hot air outlet, no hot air blowing out.

Analysis and maintenance: check the fan and heater is normal, measuring the silicon gate no trigger voltage, measuring the control transistor VI of the c pole rectangular wave signal output, suspected that the photocoupler is bad e, with a multimeter Rxl0 block measurement photocoupler ③, ④ feet between the positive and reverse resistance are infinity, the normal forward resistance should be a number of m, the reverse resistance is infinity, determined to be the internal photosensitive tube open circuit, resulting in the silicon gate Can't get trigger voltage and can't conduct. After replacing the photocoupler, the fault is removed.