Bells failing to activate

[abdi]

I was working on this 4 zone conventional system. as I was testing it, I noticed the bells were not working. The system consisted of Mannual call points only (M).

Instead of the bells going off, I get common fault led showing and the zone displaying fault condition.this happenend to all four zones.

I have checked all the MCP for damages and found them to be normal, also checked sounder circuit wiring, the eol's were there, and voltage levels was fine. checked the zone voltage levels. they were all fine.

This panel belong to a some one I know and it's not client of ours. I didn't have time to do detailed investigation.

I should mention when I arrived site, one of the zones was in fault, I traced it down to loose break glass (Gent square type)

I powered the system down, and up again. it has gone straight into fire, resetted it, push the key into the call point and the common fault condition comes up again.....

This panel belong to a some one I know and it's not client of ours. I didn't have time to do detailed investigation

your brief feedback will be appreciated.

Thanks

[Chris Houston]

My brief feedback is that this is not an issue they should wait to fix!

I would also suggest that they should have identified the problem during their weekly tests.

They must be advised to fix this problem immediatly and start complying with the British Standard regarding the testing of the system.

[Graeme]

check that the manual call points are not  the  type with no series resistor.

When you test a mcp,it will give a dead short between positive and negative thus generating a fault on the zone.

that would be what i would check first.

disconnect the zone from the panel and put a meter across the pos and neg.

test a mcp and see if you get a resistance between 470-680 ohms normally.If you get zero then it's the above.

[David Rooney]

Thinking of the "Gent Square Type" call points, I'm guessing the panel has been changed at some time, and as you say Graeme, the call points give a dead short when operated.

Abdi, have you not tried putting a 470R or 680R resistor across the zone terminals to make sure the panel works as it should first?

Doesn't the fact that operating ANY call point causes a fault ring any alarm bells with you (pardon the pun !) ?

[Allen Higginson]

Thinking of the "Gent Square Type" call points, I'm guessing the panel has been changed at some time, and as you say Graeme, the call points give a dead short when operated.

Abdi, have you not tried putting a 470R or 680R resistor across the zone terminals to make sure the panel works as it should first?

Doesn't the fact that operating ANY call point causes a fault ring any alarm bells with you (pardon the pun !) ?

Or not,as the case may be!!
Definately sounds like you have incompatible BGU's fitted.Upgrade to 470 units (you could muck about fitting resistors in the existing ones if you could be bothered)