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Topic Title: Fire alarm help
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Created On: 30 October 2017 09:28 PM
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 30 October 2017 09:28 PM
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Spark87

Posts: 5
Joined: 07 April 2013

Hello all, looking for some advice on a few issues. First one is a job currently be undertaken is in a care home which has moved a few rooms around.

One room being moved is the kitchen and on the plans it shows a heat alarm which if off the fire alarm circuit which is fine but the other thing they are asking is a smoke alarm not linked to the fire alarm circuit to allow closure of just the kitchen door if the smoke was to be set off. I have picked up a aico smoke alarm and aico relay base but not sure the best way to make it 24v to allow fitting into the door closure. Has anyone else done this before in a certain way?

Second issue is with the door closures, all of a sudden the door closure circuit on ground floor has stopped working. We fitted a replacement door hold back which worked fine but when the test release button was pressed the closure circuit became dead. The rcbo for the door closeures is on but no power at any hold backs. The fire alarm is an addresiable system ctec xfp and I could find any external relay or interface to check if the power out side. We have tried resetting the system and sounding the system but still no Lucy it's dead. Anyone had any similar issues before?
 30 October 2017 09:54 PM
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Dave69

Posts: 621
Joined: 16 July 2011

Confuzled, are you talking about magnets that hold the doors open in normal mode or proper door closures? In either case on lose of power the doors will close. Are they really 240ac or do they have 12 or 24vdc power supply which is fed viaa contact in the fire alarm panel?
Really sounds like you have a problem with the psu, the door release mechanism must be fail safe, ie in the event of loss of power all fire doors will close under their own steam
 30 October 2017 10:27 PM
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Spark87

Posts: 5
Joined: 07 April 2013

Magnetic door holders which are are open during operation for the fire alarm. The holder circuit is feed from a 16amp supply on cu and I can't see any cables going into panel apart from loop ends and power feed from fuse switch spur. I'm pretty sure it's 24v as it has a over head door closure on same circuit linked off a magnetic door hold back. Has about 10-15 on ground floor all run looped in and out surface mounted throughout. All was working fine then suddenly the doors wouldn't stay open and the loss of power, couldn't see any interface or external relay.

The over door magnetic closure is what they require to be fitted of the smoke alarm. I picked up a aico smoke and relay base but the over magnetic door closure is 24v so it needs to be stepped down coming out relay base as it states 230v out put. As it's concrete ceilings all is surface mounted but just trying to make it look tidy as it can without boxes everywear. Only way I thought to do it with the aico base was to feed into a 24v transform before going into closure but this means another box surface mounted.
 31 October 2017 12:11 AM
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mapj1

Posts: 9569
Joined: 22 July 2004

Sounds like the 24VDC has collapsed when the test release was operated. Somewhere there will be a DC supply normally as part of the fire panel, but maybe not. It may be as simple as a fuse in the output of the 24V supply, but you need to work out where it is. Are there no commissioning notes or plans?
What you need from the smoke detector are 'voltage free contacts' Now they may well be contacts on a relay whose coil is mains operated, or the electronic 'relay' equivalent.

Be aware that some door solenoid contain some electronics designed to make them pull in with a snap, by generating a locally boosted voltage that is pulsed onto the coil.
some seem ver complex for what they are

-------------------------
regards Mike


Edited: 31 October 2017 at 12:27 AM by mapj1
 31 October 2017 12:32 PM
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alancapon

Posts: 6917
Joined: 27 December 2005

Originally posted by: Spark87
. . . the door closure circuit on ground floor has stopped working. We fitted a replacement door hold back which worked fine but when the test release button was pressed the closure circuit became dead. The rcbo for the door closeures is on but no power at any hold backs. The fire alarm is an addresiable system ctec xfp and I could find any external relay or interface . . .

It sounds like you have wired the new magnet wrongly, and the "manual release" button has shorted out what is normally a 24 dc supply. You will need to replace the fuse in the power unit. With an addressable system, it is likely that the interface is a loop powered relay, located near the power unit.

Regards,

Alan.
 31 October 2017 12:37 PM
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alancapon

Posts: 6917
Joined: 27 December 2005

Originally posted by: mapj1
. . . Somewhere there will be a DC supply normally as part of the fire panel, but maybe not. It may be as simple as a fuse in the output of the 24V supply, but you need to work out where it is. . .

It is unlikely to be powered from the panel, as you wouldn't want the magnets drawing their power from the main fire alarm batteries.

Regards,

Alan.
 31 October 2017 01:46 PM
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Spark87

Posts: 5
Joined: 07 April 2013

Hi Alan

Will check the door magnetic holdback but sure it was only a + and - connection with the release button cutting the power to magnet from the + side.

With the interface will that require being changed or will it have a fuse from the out going side feeding 24v to doors which can be replaced easy enough?

Many thanks
 01 November 2017 08:43 PM
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Dave69

Posts: 621
Joined: 16 July 2011

Lets back track to the basics. What sort of fire alarm panel is it? Addressable, conventional, bi wire etc. There is no problem powering door release magnets from the fire alarm panels auxiliary 24v supply as they should be fail safe to open, so in the event of alarm or power failure they will de-energise and therefore will not drain the panels batteries,
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