Monarch T-10 Time Delay ASY 551511
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The Pyro-Chem 551511 TD-10 Time Delay Assembly is a factory pre-set time delay component for the Pyro-Chem Monarch Industrial Dry Chemical Fire Suppression System used in vehicle paint spray booth and automotive finishing applications. When the Monarch system detects a fire and the control head actuates, the TD-10 retards agent discharge for a period of 10 to 20 seconds to allow the exhaust fan to wind down before dry chemical is released into the booth. This delay is required by UL 1254 compliance testing and is a deliberate design feature, not a system limitation.
In a paint spray booth, the exhaust fan must stop before dry chemical agent is discharged. If the fan is running when agent discharges, it will sweep the agent out of the booth before it can suppress the fire, rendering the discharge ineffective. The TD-10 provides the delay needed for the exhaust fan interlock to shut the fan down after the control head fires and before agent reaches the nozzles. The system design under NFPA 17 (Dry Chemical Extinguishing Systems) and NFPA 33 (Spray Application Using Flammable and Combustible Materials) accounts for the TD-10 delay in the total system response time calculation. The control head mounts directly on the TD-10 time delay assembly during installation.
| Feature | Details |
|---|---|
| Manufacturer | Pyro-Chem (Johnson Controls) |
| Part Number | 551511 |
| Component Name | TD-10 Time Delay Assembly |
| Delay Duration | 10 to 20 Seconds (Factory Pre-Set) |
| Compatible System | Pyro-Chem Monarch Industrial Dry Chemical Fire Suppression System |
| Application | Vehicle Paint Spray Booths and Automotive Finishing Systems |
| Purpose | Delays Agent Discharge to Allow Exhaust Fan Wind-Down Before Discharge |
| Required By | UL 1254 Compliance Testing |
| Governing Standards | NFPA 17 (Dry Chemical), NFPA 33 (Spray Application) |
The Monarch system is a pre-engineered dry chemical system designed and installed by certified Pyro-Chem Monarch distributors per NFPA 17 and NFPA 33.
- Control Head Mounting: The MCH, NMCH, or ECH series control head mounts directly on the TD-10 time delay assembly using the Model MB-P2 mounting bracket. The time delay is part of the control head assembly stack, not a remote component.
- Exhaust Fan Interlock Required: The TD-10 time delay only functions correctly if the exhaust fan interlock shuts the fan off within the delay window. Fan interlock wiring must be confirmed during installation and tested at each semiannual service visit to verify it operates within the delay period.
- Semiannual Service: Per NFPA 17 and the Monarch service manual, the time delay function is tested at each required semiannual inspection to verify the correct delay interval before agent release.
- Post-Discharge: Per Pyro-Chem service documentation, the TD-10 assembly does not typically require replacement after a system actuation, but its condition should be confirmed by the certified Monarch distributor during post-discharge reset and inspection.
Why is a time delay beneficial in a fire suppression system?
In a vehicle paint spray booth, a running exhaust fan would pull dry chemical agent out of the booth faster than it can suppress the fire. The TD-10 delay gives the fan interlock time to stop the fan after the control head fires, so the booth is in a static-air condition when agent discharges. Without this delay, agent application efficiency would be severely compromised. UL 1254 requires this delay as part of the compliance test protocol for vehicle paint spray booth suppression systems.
Does the TD-10 need to be replaced after a system activation?
Per Pyro-Chem service documentation, the TD-10 time delay assembly does not typically require replacement after a system activation. Your certified Monarch distributor confirms the condition of the assembly during the post-discharge inspection and reset of the system.
