HVACopediaNTI · Boiler · Pump/purge
Circulator outputs and their fuses
What happens, in order
- PUMP A (DHW pump) is powered during a DHW call
- PUMP B (boiler pump) is powered during every call: DHW, local CH1 and lead-lag CH2; not used in every piping layout
- PUMP C (CH pump) is powered during a CH1 or lead-lag CH2 call and turned off for DHW in the single system circulator layout
- Each output can carry 3 A or a 1/6 hp motor
- Fuse A protects PUMP B (with the blower and spark generator); fuse B protects PUMP A and PUMP C
- If a pump does not run, switch it on by hand from the pump diagnostic page and check for 120 VAC at its terminals
Timings and thresholds
| Item | Value |
|---|---|
| Pump output rating | 3 A or 1/6 hp each |
| Fuse A / Fuse B | 7 A fast-acting each |
Applies to: Trinity Tft60, Tft85, Tft110, Tft155, Tft175, Tft200, Tft250, Tft300, Tft399
Models
More NTI boiler sequences
- Combustion checking procedure · Startup
- Power-on and mode sequence · Startup
- Power-up and what lets the boiler start a call · Startup
- Failed ignition and lockout · Ignition
- First ignition start-up · Ignition
- Light-off sequence and retries · Ignition
- Central heat call (CH1) from call to satisfied · Heating
- Indirect tank (DHW) call · Domestic hot water
Related
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Sequences of operation, error codes and tips work offline in the HVACopedia app.
Source: NTI Tft60-399 Installation and Operation Instructions (rev. 2012-04-09), Sec. 8.0 Lighting, Sec. 10.0 Piping, Sec. 15.0 Troubleshooting. Written in our own words; timings can differ by model and software version, so check the manual for your exact unit.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.