Heating Control

90.1-2016 BM

Preheat Setpoint

Applicability

Systems with a preheat coil located in the outside air stream

Definition

The control temperature leaving the preheat coil

Units

Degrees Fahrenheit (°F)

Input Restrictions

As designed

Baseline Rules

Not applicable

 

Heating Supply Air Temperature

Applicability

All systems

Definition

The supply air temperature leaving the air handler when the system is in a heating mode (not the air temperature leaving the reheat coils in VAV boxes)

Units

Degrees Fahrenheit (°F)

Input Restrictions

As designed

Baseline Rules

20 °F above space temperature setpoint for systems 1-4. Same as maximum reset cooling supply air temperature for systems 5-8 and 105 °F for systems 9 and 10.

 

Heating Supply Air Temperature Control

Applicability

Systems with the capability to vary heating SAT

Definition

The method of controlling heating SAT. Choices are:

  • No control – the heating coil is energized on a call for heating, but the supply air temperature is not directly controlled, but instead is dependent on the entering air temperature, the heating capacity and the airflow rate.
  • Fixed (constant)
  • Reset by coldest zone, temperature first
  • Reset by outside air dry-bulb temperature
  • Staged setpoint
  • Scheduled setpoint

Units

Degrees Fahrenheit (°F)

Input Restrictions

As designed

Baseline Rules

Fixed (constant)

 

Heating Reset Schedule by OSA

Applicability

Systems that reset the heating SAT by outside dry-bulb temperature (this typically applies to dual-duct systems or to single zone systems with hydronic heating coils)

Definition

A linear reset schedule that represents the heating supply air temperature or hot deck supply air temperature (for dual duct systems) as a function of outdoor air dry-bulb temperature. This schedule is defined by the following data points (see below):

  • The hottest heating supply air temperature
  • The corresponding (cold) outdoor air dry-bulb threshold
  • The coolest heating supply air temperature
  • The corresponding (mild) outdoor air dry-bulb threshold

sat_heating_reset.jpg

Figure 3.7.2-2: Example of SAT heating setpoint reset based on outdoor air temperature (OAT)

Units

Data structure (°F)

Input Restrictions

As designed

Baseline Rules

Not applicable