Troubleshooting, Check control module fuses

Installation & Service Manual

13 Troubleshooting

WARNING

Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Always disconnect power to the water heater before servicing. Failure to comply could result in severe personal injury, death, or substantial property damage.

Check control module fuses

	NOTICE	ALWAYS check control module fuses before
	NOTICE	replacing control module or any major


		components (blower, etc.). If one of these
		fuses is blown, it can prevent the control
		module or other components from
		operating.

WARNING Never jumper (bypass) any device except for momentary testing as

outlined in the Troubleshooting chart. Severe personal injury, death, or substantial property damage can result.

1.Turn OFF power to the water heater at the external disconnect switch.

2.Remove top access cover.

3.Remove the control module cover.

4.Inspect fuses F2, F3, F4, and F5, see FIG. 13-1 below.

Before troubleshooting:

1.Have the following items:

a.Voltmeter that can check 120 VAC, 24 VAC, and 12 VDC.

b.Continuity checker.

c.Contact thermometer.

2.Check for 120 VAC (minimum 102 VAC to maximum 132 VAC) to water heater.

3.Make sure the tank is calling for heat.

4.Make sure all external limit controls are installed and operating.

Check the following:

1.Wire connectors to control module and connection board are securely plugged in.

2.Gas pressures:

•Maximum: 14 inches w.c. (natural and LP) with no flow (lockup) or with water heater on

•Minimum: 4 inches w.c. (natural), 8 inches w.c. (LP) with gas flowing (verify during water heater startup)

Figure 13-1Control Module Fuses

F3 - 1.25 AMP FUSE

MAIN BOARD

F4 - 3.15 AMP FUSE

GAS VALVE

F5 - 5 AMP FUSE

PUMPS

F2 - 3.15 AMP FUSE

24V SUPPLY

5.The water heater is shipped with three (3) spare fuses in a plastic bag attached to the control module cover.

6.If necessary, replace open fuse (F3 is 1.25 amps, F2 and F4 are 3.15 amps, and F5 is 5 amps).

Note: Fuses F2 - F5 are all slow blow fuses.

WARNING Do not jumper fuse or replace with any fuse except as specified. Failure to comply could

result in severe personal injury, death, or substantial property damage.

7.Install control module cover and top access cover after fuse inspection.

8.Restore power to the water heater at the external disconnect switch and verify water heater operation (Section 10 - Start-up) after completing water heater service.

SNA400-125, SNR150-100, SNA285-125, SNR200-100, SNA500-125 specifications

Lochinvar has established itself as a leader in the realm of high-efficiency heating solutions, and its line of condensing boilers, including the SNA500-125, SNR200-100, SNA400-125, SNA285-125, and SNR150-100, exemplifies the brand’s commitment to innovation, efficiency, and reliability.

The SNA500-125 model stands out with its impressive heating capacity, designed for larger commercial applications. Featuring advanced modulating burners, it can precisely adjust its output based on real-time demand, significantly enhancing energy efficiency. The stainless steel heat exchanger ensures robust durability and improved thermal performance, while the integrated controls offer advanced diagnostic capabilities and user-friendly operation.

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The SNA400-125 delivers a robust solution for diverse heating needs, equipped with state-of-the-art modulation technology that not only optimizes efficiency but also offers quiet operation – a crucial feature for facilities where noise reduction is paramount. This model also includes built-in redundancy options, enhancing reliability during peak operational periods.

The SNA285-125 provides a balance of performance and efficiency for smaller commercial settings. Its innovative control system offers precise temperature management and easy integration with existing systems. Energy Star certified, this model is not only cost-effective but supports sustainability efforts in various industries.

Lastly, the SNR150-100 is ideally suited for light commercial applications, featuring a compact footprint and excellent heat transfer capabilities. The user-friendly interface and robust safety features make it an excellent choice for operators prioritizing both ease of use and reliability.

All these models incorporate Lochinvar's commitment to superior design and advanced technologies, setting a benchmark in the high-efficiency heating market. With a focus on long-term performance and compliance with modern environmental standards, Lochinvar continues to deliver top-tier solutions tailored to meet diverse customer needs. Whether for large-scale operations or smaller settings, these boilers represent a significant advancement in commercial heating technology.