Hand dryer fault resolution

Abstract:How do I do if my hand dryer is broken? Now many places will use the hand dryer, the hand dryer does bring a lot of convenience to people, the hand dryer will also have a failure of the time, such as, the hand dryer indicator light does not light, also does not work; no hot air blowing out, only cold air blowing out; indicator light is on, but the induction sensitivity is low, etc.. So, how to repair the hand dryer is broken? This article is a simple introduction for everyone!

Common faults with jet hand dryers

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

Analysis and maintenance: there is cold air blowing out, that the blower motor is powered to work, infrared detection and control circuit is normal. Only cold air, that
The heater is broken or wired loosely. Upon inspection, the heater wiring is loose. After reconnection, there is hot air blowing out, the fault is removed.

Fault phenomenon 2: after the power, the hand has not been placed on the hot air outlet. Hot air that is out of control blowing out.

Analysis and maintenance: after checking, silicon controlled no breakdown phenomenon, suspected of photocoupler ③, ④ feet of internal leakage of phototransistor 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 the heater is normal, measuring the silicon gate without trigger voltage, measuring the control triode VI of the c pole rectangular wave signal output, suspected that the photocoupler is bad e, with a multimeter RxI0 block measurement photocoupler ③, ④ feet between the positive and reverse resistance are infinity, the normal forward resistance value should be a number of m, reverse resistance value is infinity, determined to be the internal photosensitive tube open circuit, resulting in the silicon gate can not get trigger voltage and can not conduct. After replacing the photocoupler, the fault is removed.

Fault phenomenon 4: power on the light is on, but no hot air blowing out after reaching.

Analysis of the fan and the heater at the same time the possibility of failure is very small, mostly seen as a bad relay or not action, and J not action may be V3 not conductive; op amp no output. D6, D5 failure; V1, V2 did not start or 7812 damage caused by no 12V voltage. Check first to measure the presence of 12V, if there is, reach out and test the op-amp (7) pin level has not changed. If there is a change, check V3 and relay backwards; if there is no change, check forward op-amp circuit, photoelectric conversion and oscillation circuit.

Fault phenomenon 5: power on the indicator light, but the induction sensitivity is low.

This fault in addition to the op amp circuit has anomalies, mostly seen for the red launch and receive tube is dust pollution, cleaning can be.