Boiler Replacement
- Refer to Volume 3, Chapter 6 for additional design requirements. Refer to 6.3.6 for Building Controls.
- Large interior equipment replacement: must plan for future replacement path/openings and maintenance. Where openings in walls, ceilings, etc. are required, this scope must also be identified.
- When replacing boilers and a BAS system does not exist or will not be provided as part of the project (Review with CPS before proceeding with design), a local stand alone control/staging/rotation/setpoint adjustment/scheduling panel with outside air temperature sensor and bacnet card for future integration to a BAS shall be provided.
- Efficient Condensing Boilers: are preferred and shall replace non-condensing hot water boilers when indicated in order magnitude scope. It is common at the time of boiler replacement to change the system pumping arrangement from constant volume to variable primary (preferred) or constant primary / variable secondary for better control and energy reduction. Obtain direction from CPS during schematic stage of design.
- Steam Boilers: When steam boilers require replacement, review options of converting the system from steam to condensing hot water with CPS. CPS preference is to move away from steam (both low and high pressure) when cost effective. Evaluate the conversion of high pressure steam systems to low pressure steam systems.
- Chemical Treatment: New shall be provided as part of boiler replacement projects. Steam boiler plants require water softeners.
- Feedwater Units and Condensate Units: shall be evaluated as part of boiler replacement projects. Feedwater units shall include two pumps per steam boiler.
- Existing Flue: Sizing/routing shall be evaluated as part of any boiler replacement.
- New burners when replaced on existing boilers have greater turn down which results in lower flue gas temperature and flowrate witch damages existing chimneys and condensing boilers will damage existing flues not designed for condensing applications. Modifications / replacement of flues may be required. EOR to evaluate and modify/replace existing flues/chimneys/breaching.
- Site Gas Service:
- Often the utility can increase the service pressure at the building from 6” WC to 2 PSIG cost effectively. If increased, the branches serving low pressure appliances like kitchens, dryers, science labs, shall remain on dedicated 6” WC lines. Boilers, water heaters, generators, RTUs may utilize the higher pressure with adjustment/replacement of regulators at each unit. When service pressure is changed, all downstream connected piping shall be leak tested per the local utility (authority having jurisdiction).
- CPS preference is to eliminate gas boosters from projects when possible.
- Combustion Air Openings: for boiler replacement, verify openings are adequate for new equipment and current codes. CPS preference for condensing boilers and water heaters is individual fully ducted combustion air.
- Flue Discharge: where a new location is required, coordinate with all building openings and exterior features. CPS preference is to provide separate flues for each boiler and water heater.
- Carbon Monoxide and Boiler Room Kill Switches (Required at all boiler room doors for all gas fired indoor equipment with 400 MBH or higher input for boilers and water heaters): Confirm they exist, are code compliant and functional. Provide / replace as required.
Boiler Refurbishment
- Boiler testing: Test the boilers (hydro / combustion) to confirm the extent of work prior to completion of design.
- Boiler tuning / Refurbishment: shall be included in scope
- Tuning required for all burner and boiler replacements.
- Boiler refurbishment often includes: replacement of relief valves, hand holes, gaskets, safeties, pressure gauges, thermometers, refractories, tubes (all or selective based on test results), etc. EOR to confirm.
- Where boiler and associated piping insulation is damaged/missing replace insulation.
- Steam boiler refurbishment: Identify and test all steam traps throughout the system. Replace failed traps.
- Existing flue sizing/routing: shall be evaluated as part of any burner replacement.
- New burners have greater turn down and may require modifications to existing flues to prevent condensation damage at low fire.
- Conversion from high pressure to low pressure steam: verify all existing steam piping sizing based on new operating pressure.
- Carbon Monoxide and Boiler Room Kill Switches (Required at all boiler room doors for all gas fired indoor equipment with 400 MBH or higher input for boilers and water heaters): Confirm they exist, code compliant and functional. Provide / replace as required.