Haydon HAY-PSUEN54-1A EN54-4 Power Supply | 24V DC, 1A, Small Enclosure
£98.62 (inc VAT: £118.34)
Key features
- Amber LED gives detailed engineer fault codes
- Small enclosure houses two 7Ah batteries
- GEN and EPS volt-free fault reporting outputs
Downloads
Summary
The Haydon HAY-PSUEN54-1A is a 27.6VDC uninterruptible power supply (PSU) built to feed auxiliary devices on a fire alarm system, and its amber diagnostic LED gives you detailed engineer-level fault codes straight from the front panel rather than leaving you guessing at a single fault indicator. That matters when you’re called back to a site months after commissioning and need to identify a battery, charging or output fault in minutes, not hours.
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Combined with separate GEN and EPS fault outputs, you get fault reporting that integrates cleanly into the wider fire system without extra interface gear. The small metal enclosure takes two 7Ah batteries, making it a practical fit where panel space is at a premium but you still need reliable standby power for auxiliary devices such as sounders or interfaces drawing up to 1A.
Features
- Amber diagnostic LED - gives engineer-level fault codes on site without needing a laptop or test kit
- GEN and EPS fault outputs - volt-free solid state relay contacts report mains loss and system faults back to the panel
- Battery monitoring - detects low battery voltage, incorrect connection or a short circuit automatically
- Deep discharge protection - disconnects batteries below 21V to prevent damage from over-draining
- Two-stage battery charging - bulk charges to 80% capacity within 24 hours, then float charges to 100% within 48 hours
- Temperature-compensated charging - adjusts charge voltage using the supplied battery temperature sensor
- Overload protection circuit - protects the PCB from damage during a short circuit or overload on the output
- EN54-4:1997 +A1 +A2 compliant - certified for use with compliant fire detection and alarm systems
Specifications
| Rated Voltage And Frequency | 110-240V AC, 47-63Hz |
|---|---|
| Input Current | 0.3A |
| Mains Fuse Rating | F3A |
| Output Voltage (Mains Power) | 22.0-27.6Vdc |
| Output Voltage (Battery Standby) | 20.0-26.0Vdc |
| Ripple | <100mV |
| Output Fuse | F1A |
| Battery Fuse | F1A |
| Imax A (With Charging) | 1A |
| Imax B (No Charging) | 1.5A |
| Battery Capacity | 2 x 7Ah |
| Maximum Battery Internal Resistance | 5Ω |
| Minimum Current | 0.1A |
| Battery Charging Method | Two stage: constant current bulk charging to 80% within 24 hours, float charging to 100% within 48 hours |
| Constant Current Charge | 0.5A |
| Temperature Compensation | -30mV/°C (0-50°C) |
| Low Battery Voltage Trigger | 23V |
| Deep Discharge Protection Cut Out | 21V |
| GEN Fault Output | Normally closed, 0.50A @ 60Vdc, 0.9Ω solid state relay, volt free; opens on mains failure with battery below 23V or PSU fault |
| EPS Fault Output | Normally closed, 0.50A @ 60Vdc, 0.9Ω solid state relay, volt free; opens if mains loss exceeds 10 seconds |
| Operating Temperature | -20°C to +45°C, 20-90% RH non-condensing |
| Storage Temperature | -25°C to +85°C, 10-90% RH non-condensing |
| Enclosure Material | 1.2mm steel, white powder coated |
| Enclosure Dimensions (W x H x D) | 275 x 330 x 80mm |
| Weight Excluding Batteries | 3.1kg |
| Weight With Batteries Fitted | Approximately 8kg |
| Approvals | EN54-4:1997 +A1 +A2; EMC 2014/30/EU; LVD 2014/35/EU; RoHS2.0 2011/65/EU; Environmental Class II |
FAQ
It’s designed for two 12V 7Ah sealed lead-acid (SLA) batteries, wired in series using the short bridging wire supplied. The bridging wire connects the positive terminal of one battery to the negative of the other, and the batteries sit inside the small 275 x 330 x 80mm enclosure. The green LED confirms mains power is present, the yellow LED flags a general fault, and the amber diagnostic LED gives a flash-count code for the specific fault, for example two flashes indicates the PSU isn’t seeing batteries. Refer to the fault finding guide to match flash patterns to the likely cause before deciding whether to investigate further or call the service provider. Yes, both are volt-free, normally closed, solid state relay contacts rated at 0.50A at 60Vdc. Keep any circuit you connect to them below 60Vdc, and remember EPS opens after mains loss exceeding 10 seconds while GEN opens on mains failure with battery voltage below 23V or on an internal PSU fault. Yes, it should be fed from a dedicated mains circuit with a labelled Mains Isolation Switch, fused at a maximum of 5 amps. The unit must also always be earthed, and the mains cable should enter through a different knockout to the low voltage cabling. Haydon recommends a minimum of 0.5mm² for the output cable on 1A and 2A models, with earth included if required. Use the knockouts provided and secure cables to the internal anchor points with cable ties as you route them in. A continuously flashing yellow LED with no batteries or temperature sensor connected is expected behaviour at initial power-up. Once the batteries and the supplied temperature sensor leads are connected correctly, this should clear within a few seconds during commissioning.What batteries does the HAY-PSUEN54-1A take?
How do I read the fault LEDs on site?
Can I connect the GEN and EPS outputs to my fire panel?
Does this PSU need its own mains supply?
What cable sizes should I use for the output?
Why does the yellow fault LED keep flashing after installation?
Downloads
- Datasheet (Adobe PDF)
Additional information
| Output Current | 1A |
|---|---|
| Device Type | |
| Battery Charging | Yes |
| Maximum Batteries | 2 × 7Ah |
| Colour | |
| Mounting | Surface |
| Fault Relay / LED |



