Gas-Fired Condensing Boilers: Greenstar FS/Combi FS Inspection and Maintenance

DANGER: Explosion!

• Close the gas cock prior to working on the gas train.

• Check for gas leaks after carrying out work on the gas train.

DANGER: Risk of flue gas poisoning.

• Check for leaks after carrying out work on the venting system.

DANGER: Risk of electric shock!

• Always disconnect the appliance from the mains power before performing any work. Disconnect the emergency shutoff switch or disengage the heating system circuit breaker. Take measures to prevent accidental reconnection.

NOTICE: Insufficient antifreeze can accelerate corrosion.

• Frost protection level has to be checked annually during the regular scheduled maintenance of the condensing boiler.

NOTICE: Damage to the coating of the heat exchanger.

• Cleaning of the heat exchanger should not be necessary until five years after the initial commissioning.

• Only use a Bosch cleaning blade or Bosch cleaning brush.

• Only clean heat exchanger if soiling is clearly visible.

NOTICE: The Heatronic boiler control can be damaged by leaking water.

• Cover the Heatronic prior to working on water filled components.

The following analytical tools are needed for service and maintenance:

• Electronic flue gas analyzer for CO2, O2, CO, and flue gas temperature

• Pressure gauge 0 to 12 inches W.C. (0 to 30 mbar)

• pH Test strips

• Glycol tester of antifreeze is being used

• Special tools are not required.

• Approved lubricants are: – For parts touched by water: Unisilkon L 641 (part-# 8 709 918 413 0) – or fittings: HFt 1 v 5 (part-# 8 709 918 010 0).

After the inspection/maintenance:

• ▶ Re-tighten all loosened threaded connections.

• ▶ Restart the appliance (page 51).

• ▶ Check all connections for leaks.

• ▶ Check the gas-air ratio and adjust if necessary (page 64).

Calling up the latest fault (service function 6.A)

• ▶ Select service function 6.A (page 61)

Fresh water filter (only combi boiler ZWB..-3A)

• ▶ Close cold water tap.

• ▶ Depressurize the cold water pipe.

• ▶ To access the filter remove the safety clip (step 1), pull out the pipe (step 2), and remove the filter from the pipe (step 3).

• ▶ If necessary, clean with plastic brush under running water.

If the DHW output on the combi boiler is significantly reduced:

• ▶ Check filter in the cold water pipe for contamination ( Fig. 68).

• ▶ Depressurize the appliance.

• ▶ Remove plate type heat exchanger and replace -or-

• ▶ Descale with descaling agent approved for stainless steel (Grade 316-1.4401).

To remove the plate type heat exchanger:

• ▶ Unplug electrical connections.

• ▶ Remove hose from safety relief valve.

▶ Remove the plate type heat exchanger.

• ▶ Install new plate type heat exchanger with new gaskets and reconnect the hydraulic assembly in reverse order.

• ▶ Check all connections used during maintenance for leaks.

Checking the electrodes

• ▶ Remove electrode set (page 10 / 12) including gasket and check electrodes for contamination; clean or replace, if required.

• ▶ Reinstall electrode set with new gaskets and check for leaks.

NOTICE: Damage to the coating of the heat exchanger.

• ▶ Cleaning of the heat exchanger should not be necessary until five years after the initial commissioning.

• ▶ Only use a Bosch cleaning blade and Bosch cleaning brush

• ▶ Only clean heat exchanger in case if soiling is clearly visible

For cleaning the heat exchanger, use Bosch main heat exchanger gaskets, the heat exchanger brush and the heat exchanger cleaning blade which are available as spare parts.

• ▶ Remove the condensate trap (steps 1 and 2) and place a suitable container underneath.

▶ Clean the condensate tray (with reversed brush).

• ▶ Rinse the heat exchanger with water from the top.

• ▶ Clean the condensate trap connection.

• ▶ Close the inspection opening again using a new gasket and tighten the screws with approx. 3.69 ft.-lbf. (5 Nm).

▶ Remove condensate trap (steps 1 and 2) and check heat exchanger orifice for clear passage.

• ▶ Remove and clean the condensate trap lid.

• ▶ Check condensate hose and clean if necessary.

• ▶ Fill the condensate trap with approx. 1 cup (1/4 l) of water and reinstall it.

Checking the mixer diaphragm

• ▶ Open the mixer unit.

• ▶ Carefully remove the diaphragm from the fan air intake and check for contamination and cracks.