Fire Alarm Repair First Fix and How to find a Fault
First Fix Repair
When repairing fire alarms, the most important challenge is to achieve a “first fix” and limit the downtime of the equipment. This requires Fire Systems Ltd, to get the following right:
- To make sure the initial diagnosis is clear and all the correct information is collected when the call is logged..
- An engineer is to be assigned to the call that has sufficient experience and technical ability to undertake the task.
- The engineer will have the available parts for that particular system within their vehicle stock to resolve the issue
- The engineer will have sufficient time to complete the work.
- Providing our engineers access to the Service history of the site.
What we have implemented to target the five points above:
Clear Diagnosis of the Fault
Our office operators responsible for taking the initial call have had technical training on fire alarms out in the field This training helps them to understand in more detail the fault being described by the person reporting it. Their technical skill level is such that there are occasions when the operator has been able to resolve the issue over the phone without the need for a site visit.
Assign Engineer with correct Skill Level
Our database has the facility to grade the skill level of our engineers according to their experience and technical ability. The operator will usually know which engineer is suitable for which site, however, if in doubt the operated can refer to the grading system within the database.
Allow Engineer Sufficient Time
To ensure that the assigned engineer has sufficient time to investigate the fault, the operated will refer to the “Engineers Schedule Planner” and if required rearrange the planner for the engineer allowing them enough time to rectify the fault.
Access to Site History
Our engineers always have access to the history of each job they attend. This information is contained in our IT management maintenance system, which can be accessed via the engineers PDA.
Vehicle Equipment Stock
All levels of Fire Systems Ltd personnel, appreciate the importance of having a well-equipped van stock. Therefore, we have implemented the various procedures to ensure that an engineer either has the correct parts within his van or they are able to source the item within a 4-hour window.
The engineer is allocated a spare parts list. At the start of the working week, the engineer checks his stock and confirms the stock is as per the list allocated.
We are currently implemented within our Operations Management Software an (App/Module), that monitors the use of the materials used by the engineers. As the engineers complete their reports stating what material was used on each job, the software is deducting the amount from our stores. When that particular item goes below a predetermined set valve the person in charge of the stores will reorder the necessary equipment. Any regularly used item that we cannot order and obtain within 24 hours is kept in our stores in the office.
We try and use suppliers that can offer same day delivery and are local.
If an engineer is working on a job and requires a part that is not within his van stock, while servicing or fault faulting, Our stores person will either take the item from our office stores to the engineer or arrange for the item to be delivered to the engineer while he is still on-site.
The measures above have ensured that we are able to fix items on our first visit to site.
Using our IT management maintenance and reporting system, we are currently putting together a program to measure the first fix performance and this will enable us to measure our performance and improve on any areas that may need addressing.
Repairing a Fire Alarm System
Repairing a fire alarm is a lot easier today due to the fault monitoring features on all the detection and alarm circuits. The fault monitoring features will also apply to the power supply, batteries, and electrical mains 230v supply.
Conventional and Addressable fire alarm systems monitor the detection and sounder circuits in different ways.
Fault Finding on a Conventional Fire Alarm System
The conventional system has radial circuits for the detection and Sounders. These circuits are monitored by having a device, which can be an EOL (End of Line) resistor or a module, located at the furthest part of each radial circuit.
The control panel continuously looks for the EOL device, should the cable be cut (open circuit) or shorted (Closed circuit) the panel can no longer see the EOL and the panel will initiate a fault with a light and sounder indication. Along with common fault light, you may have an additional light under a zone LED (Light Emitting Diode) or Sounder LED inside the panel. To locate this fault, the engineer will remove the faulty pair of cables from the panel and by using his electrical meter and breaking down the circuit in difference places, will trace the reason for the open or short circuit. When the issue has been cleared the engineer should be able to measure the EOL on his meter and once he can read the unit, he can insert the pair of cables back into the panel and the fault should clear.
Fault Finding on an Addressable Fire Alarm System
On the Addressable systems the circuits are not redials, but start from the fire control panel and return to the panel forming a loop or ring circuit. Due to the system being intelligent, it allows for both detection and Sounders to be wired into the same circuit. (This can also be done on conventional Sav or 2 wire system). However, it is more commonly found on Addressable systems. T
Open Circuit Fault
The loop is continuously monitored by the onboard processor send data to all the devices on the circuit and receiving a reply from each device in a fixed period of time. Should a device not respond within the allocated time period, the panel will register a fault on the LCD display identifying the missing device in the form of a text location message. However, should an open circuit occur, the panel display will show “Open circuit” fault stating which loop it is affected. It is good to note, that all the devices will still operate as the panel can still see all the devices with one open circuit fault.
To locate an open circuit on the detection loop, you need to remove one end of the circuit from the loop terminals, leaving only one end remaining. The control panel will now list as a fault all the devices it can no longer communicate with, the list should proceed right up to the break within the detection loop. If you are fortunate enough to have a drawing showing the device numbers, then this will give you a pretty good idea to the location of the open circuit. You can do the same thing again but this time use an electrical voltmeter to trace the voltage around the circuit.
If you are chasing a short circuit on an addressable circuit, you will have to remove both ends from the loop terminals and use a meter that can read resistance and trace the fault measuring the resistance as you go around the circuit. The closer you get to the short circuit, the lower the resistance.
However, tracing faults can be difficult if there are isolators fitted on the detection loop. If this is the case, it is best to bypass them by linking them out so that the voltage or resistance can be measured by the relevant test equipment.
Earth faults can be difficult to trace, a starting point, is you have to establish whether the earth is on the fire alarm control panel or the external wiring circuits. To establish this, you have to remove all the external wiring from the control panel, then using an electrical test meter to check to see if the earth fault on the panel has cleared. If it has, you know the fault is on one of the external circuits. However, should it still be on the panel, then by using a process of elimination, you should be able to trace the fault to one of the circuits boards or the power supply.
If the earth is on the external wiring, then first you have to establish which circuit has the fault. You can use a test meter or by placing a circuit back onto the panel one at a time and observe when the earth returns, will tell you which circuit has the problem.
Once you know the circuit, you then have to use your test meter and break the circuit down, into sections until you locate the affected piece of cable.
With intermittent faults, it depends on how frequent the fault occurs, if it is every ten mins or less then you can work on the system until you clear the fault. However, should the fault occur every hour or more, like once a day or week, they are usually very little you can do, except make a change to the affected part of the system. Then by using a process of elimination, return after a suitable period of time and see whether the fault has stopped or moved to another part of the system as per your expectations. On locating the fault, you can make the necessary repair.