Hot Water Heating > Service Boiler Burners and Heat Exchangers

Existing Conditions

Flue gas analysis on the existing boilers shows combustion efficiency ranging from xxx to xxx, which is below the operating capability.

Retrofit Conditions

The boilers could benefit from a tune-up by a qualified heating mechanic. This simple activity will increase operating efficient by about xxx%.

Further Benefits

A tune-up will increase capacity, improve reliability, and extend the life of boiler and water heaters.

Application Details

Depending on the boiler design, the following actions should be taken:

1.	Clean the fire side of the heat exchanger.

2.	De-scale the water side of the heat exchanger.

3.	Clean the burners.

4.	For atmospheric boilers, check and adjust the gas pressure in the manifold.

5.	For forced draft boilers, adjust the air and gas flow rates for all firing stages or across the firing range for modulating burners.

Issues and Concerns

Boiler service requires a qualified tradesperson, however owner staff can perform regular visual inspections. Watch for the following warning conditions:

•	A soft, lazy yellow flame.

•	A hard blue flame.

•	Dirty or sooty heat exchanger surfaces.

•	Broken heat exchanger (big flame area rather than individual holes) on atmospheric boilers. This looks a lot like a broken burner on a gas barbecue.

•	Damaged combustion chamber walls.

•	Backdrafting (combustion products coming into the boiler room rather than leaving through the stack).

•	Flame roll-out from the burner to the exterior of the boiler cabinetry.

•	Condensation in boiler or vent (visible either as dripping or as corrosion and streaks around the joints.

References

Conforms to recommendations in "Energy and Water Efficiency in Multi-Unit Residential Buildings", Canada Mortgage and Housing Corp.

Analysis