5.3102.35 Upgrade to a Combined Heat and Domestic Hot Water System

Hydronic Heating (Hot Water and Steam)
Equipment Installation
Desired Outcome: 
Increased efficiency of existing system
Check for presence of asbestos-containing materials (ACMs)

Potential ACMs will be handled in accordance with SWS 2.0110.2 Potential Asbestos-Containing Materials

Ensure a safe work environment


Field and site conditions will be verified to determine if scope of work is applicable

It will be determined if higher efficiency system and optimal control strategy are possible

Contractor will verify capacity of domestic hot water ( DHW DHW Domestic hot water ) and system choice

Ensure optimal system is applied


Existing stand-alone DHW DHW Domestic hot water components, as identified by the scope of work, will be removed and disposed of in accordance with local codes and laws

Ensure safe removal and disposal of orphaned equipment Orphaned equipment Condition when one smaller combustion appliance exists after being commonly vented with a larger appliance. What remains is a larger exhaust flue or chimney than is necessary for the remaining smaller appliance

Add indirect domestic hot water heater

Heating water system will be cleaned and flushed

Strainer will be installed on boiler water supply side of heat exchanger in accordance with manufacturer specifications

Equipment will be installed in accordance with manufacturer specifications and will include:

  • New indirect tank or heat exchanger and storage tank
  • Pumps
  • Controls
  • Expansion tank
  • Flow controls
  • Insulation

Equipment will be installed on concrete pads as required; for applicable climates, freeze protection will be incorporated into the system using a glycol loop separated by heat exchanger or a drainback system

Ensure water system is clean

Properly install system


DHW DHW Domestic hot water production, distribution system, and delivery temperature will be tested for proper and safe operation

Water flow through the boiler, pressure, control sequences, operating amperage, and voltage shall be measured in accordance with ANSI ANSI American National Standards Institute, www.ansi.org / ACCA ACCA Air Conditioning Contractors of America, www.acca.org Standard 5 or ANSI ANSI American National Standards Institute, www.ansi.org / ASHRAE ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org Standard 111 and adjusted to meet design requirements

Contractor will confirm performance to manufacturer specifications

Contractor will confirm intent of control strategy:

  • Winter and summer modes/ operation
  • DHW DHW Domestic hot water priority
  • Lead-lag/sequencing
  • Modulation

Ensure system operates safely and efficiently


Property manager will be educated on proper operation and maintenance

Maintain optimal performance