andilong

Hello, I have just moved into a new house and i'm seeking out some advice. The house has an alarm system installed, for which the previous owner has left the code. The alarm box on the outside has "british gas" on it but the key pad panel has no branding at all. I think the alarm may have been operated / serviced by dyno as there has been a letter addressed to the previous owners with "dyno locks and alarms" on it ? The alarm has 1 magnetic contact on the hall/entry door which sounds a beeper whenever opened and there are 3 PIR sensors fitted at the other points of entry downstairs. I'm sorry if this is a little vague but this is the only information i have as i have never owned an alarm system before and didnt exactly get a "hand over" from the previous owners. anyway i have a couple of questions i would like answering if possible ? 1. the panel currently displays the message " supply trbl" i havent used the alarm since moving in but what does this mean ? 2. what options do i have with this alarm system ? can i just set it and leave ? presumably its not monitored so if it goes off it will just beep until i reset it ? 3. can i have the alarm monitored / serviced by any company or does this have to be the company who installed it ? 4. if i no longer want the alarm do i have to contact someone to take it out ? or can i just remove it ? Thanks in advance for your help