A.6 Boiler High Limit Temperature Controller
•When water temperature reaches setpoint, controller ends heating cycle.
•When water temperature drops below setpoint minus differential, controller restarts heat cycle to
•If water temperature exceeds maximum allowed temperature (220°F or 104°C), controller enters manual reset lockout state.
•For models having reset capability, press any onboard button or cycle power to reset.
Figure 20 - Basic Control Algorithm Example
A.7 Troubleshooting
•Following service procedures are provided as general guide.
•On lockout and retry models, meter readings between gas control and ignition module must be taken within trial for ignition period. Once ignition module shuts off, lockout models must be reset through key buttons and display. On retry models, wait for retry or reset at thermostat.
•Check for correct installation and wiring before replacing any component.
•Control module cannot be repaired. If it malfunctions, it must be replaced.
•Use only qualified service agent to service ignition systems.
1.Perform checkout as first step in troubleshooting.
Check troubleshooting guide to pinpoint cause of problem. See Table 7 , page 30.
2.If troubleshooting indicates ignition problem, see Ignition System Checks to isolate and correct the problem.
3.Perform checkout procedure following troubleshooting guide again to verify system is operating normally.
A.8 Troubleshooting Error Codes
Integrated boiler control uses advanced diagnostic capability to assist in troubleshooting error conditions.
Table 6 page 28 shows codes that could arise on integrated display during fault.
Suggestions are provided in Table 6 for servicing these potential errors.
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