NTI Boiler: Clean the DHW filter (combi models only)
Clean the DHW filter (combi models only) on a NTI boiler: If you have a combi and the hot water has gone weak or lukewarm, or the boiler will not see the flow, the first thing to look at is the DHW inlet filter and the flow meter turbine. They collect grit and scale, especially on new plumbing or after the city does work on the main. Cleaning them is a simple job, but the domestic side has to be valved off and drained first so you are not working under pressure. It takes about twenty minutes and often fixes the complaint outright.
Applies to: TRX150 combi models
Common causes of clean the dhw filter (combi models only)
- Debris or scale clogging the DHW inlet filter
- Grit jammed in the flow meter turbine so it spins slowly or not at all
- Recent plumbing work or water main disturbance sending sediment into the combi
- Hard water scale building up on the turbine over time
How to fix clean the dhw filter (combi models only): step by step
- Valve off and drain the combi DHW circuit before starting.
- Remove the clip on the flow meter, then remove the flow meter cap.
- Remove the flow meter turbine and check that it spins freely by hand.
- Remove the filter and clean it with a toothbrush and clean running water.
- Reinstall the filter, turbine and cap, making sure everything seats fully.
- Refill the DHW circuit and purge it following the filling and purging instructions.
- Restore gas and power, check for leaks at the work area, and run a hot water draw to confirm flow is back.
If the unit shows an error code, look it up: NTI Boiler codes
Source: NTI TRX150 manual, p. 98. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.