British Gas / DSC Alarm

[scoob]

Hi,

I've got a British Gas Burglar Alarm (Really a DSC Ltd Alarm) and I was wondering if anyone knew where I could buy a door contact for it?

BG want £85 + parts + VAT to fix it. I've tried a standard contact from Maplin which didn't work and have since learned that it needs to be a DSC part due to there being an extra transister in the contact itself.

Any help greatly appreciated.

Thanks,

Chris

 

[breezer]

assuming you own the alarm, take an existing door contact off and use a meter to find out what the valuse of the resistor is.

its very unlikely its a transistor as you said

then by the same value of resistor from maplin and fit it in the same confiuration (either in paralel or series with the contact.

I only hope you can not see the letters ID on the alarm, as these are called "biscuits" and maplin dont sell them

 

[scoob]

Hi Breezer,

Thankyou so much for your speedy response!

Sorry I meant resistor. I've found a manufacturer - Ventcroft who make the parts, and it states a 5kB Shunt, 5kB EOL.

Does this mean I need a 5kB resistor?

Also, where would I see the letters ID on the alarm?

Thanks,

Chris

 

[Adam_151]

Hi Breezer,

Does this mean I need a 5kB resistor?

That doesn't make sense? are you sure that where ever you are reading that from doesn't say 5k8 ?

 

[scoob]

Sorry it reads 5k6. I cut and pasted the three digits to notepad as the site uses a poor font...

 

[Adam_151]

Sorry it reads 5k6. I cut and pasted the three digits to notepad as the site uses a poor font...

Yeah that makes more sense , I was thinking after I posted my other message that it was unlikely to be 5k8 as its not a 'prefered value'

 

[scoob]

Is this 5k6 the value of the resister I need to buy from Maplin? Also I've looked at the door contact and it has three terminals, but doesn't appear to have one of the bisucits attached to it.

I had a look at biscuits from an alarm system and the appear to be a flat rectangular box with three wires coming out of it?

Am I going along the correct lines?

Thanks,

Chris

 

[Adam_151]

Is this 5k6 the value of the resister I need to buy from Maplin?

yeah, and reckon a 5% carbon film quater watt part will be fine

I had a look at biscuits from an alarm system and the appear to be a flat rectangular box with three wires coming out of it?

Think you are going to have to wait for breezer on that one, the only biscuits I understand are the ones that sometimes have chocolate on them

 

[scoob]

Brilliant - Thanks for your help!

 

[breezer]

scoob, yes those are the biscuits in question just like

these.

but dont worry about them or ID (thats what the biscuits are, ID biscuits)

back to yours

EOL means End Of Line so if you are adding the new door contact to an EXISTING door circuit you will not need an EOL resistor, but you WILL need the shunt resistor

Basicaly what happens is when all devices are closed the panel sees the EOL resistor, when any device opens it sees the EOL AND shunt resistors so it knows a device has opened, if it sees a dead short it knows it is being tampered with, or if it sees no EOL resistor it knows the cable has been cut

so as i said if you are adding to a an existing door circuit you only need to ad the shunt resistor (buy a couple in case you break one)
The shunt resistor should be wired across the actual contact (silver screws) and the contact the wired in series, also solder and sleave any joints you make as bad connections will cause falso alarms

and don't put your door on the same circuit as any detectors only put it on a door circuit

 

[offroader]

Dont BG fit expensive/rubbish wireless alarms?

Anyway if its a wired system, can you not share a zone, and wire in series?

 

[ebee]

A plubing/heating engineer of many years standing said to me "British Gas! I wouldn`t even let them clean my windows"