hi all,

 

i have a system of menvier m12 smoke detectors connected to my alarm system and powered seperately by an elmdene 1amp psu and this has been working fine until today when i noticed the psu had no lights on and none of the detectors were flashing which i find unusual as surely if the psu failed the alarm relay in each detector would open and set off the system which would then show me the fault?

i'm not sure what has happened as i don't have time to look into it until the weekend so does anyone know what the issue might be?

 

don't worry i am using battery powered detectors until then

 

thanks in advance

Something is wired wrong?

PSU should ideally signal a fault to the controls too.

could be......but it's all been working fine for about 5-6 years and it's only today i noticed the psu was dead,

i would have just thought for safetly the smoke detectors would default to opening the relay upon power loss

Most closed loop security and fire equipment is wired NC with open on loss of power.

thats what i thought, but i've had no alarm conditions or anything and as far as i know the alarm still works fine.

 

i don't believe a psu and a zone exander card could fail like this at the same time it just doesn't make sense to me

hi just an update,

 

i opened up the psu today and although nothing visually looked wrong upon closer inspection i noticed battery acid under the battery and when i removed the battery i saw it had leaked all over the leads, the back of the psu and itself.

i then measured the voltages and the battery was 0.04v so very dead and i had no output from the transformer or from the output of the board then i measured the voltage of the cabled going into the terminal block and i got the correct 230v so i believe the transformer has failed and not knowing what else that could have damaged i will be ordering a new psu.

 

many thanks for your help

But why did the circuits not operate?

Is the expander powered from the same PSU?

 

It opens in alarm,no power no alarm 

id of thought the power going off completely would cause an alarm. I'm assuming there was enough power to keep them closed. One of many reasons you shouldn't use them vs dedicated fire detection.

I meant test it with power restored  if it alarms all is fine,the term all was fine before hand often means it was never tested to prove it actually does work