Wolf FGB-K Series Installation And Maintenance Instructions For Contractors page 74

Tightening the fitting on the gas
combination valve
Filling the trap
Control reading
Heat exchanger pressure
differential after cleaning
74
28.9. Assembling the heat exchanger
- Replace the threaded connection seals
- Tighten the threaded connection on the gas combination valve and check for
leaks.
- Fill the trap from above through the inspection port in the flue pipe/bend.
Fill only through the flue; do not fill water into the ventilation air
aperture, as this could cause the burner to malfunction.
- Carry out test as described in chapter 28.4, Determining the soiling level on
the heating water heat exchanger.
- The measured pressure drop values must lie below the limits.
- If no improvement is apparent, install the "heat exchanger" spare part.
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