installation, operating and service instructions eva series boiler

VIII Appendix A –Temperature Controller Operation for Modulating Boilers
A. Description
The microprocessor based temperature controller is utilized for all modulating Thermal Solutions water boilers. The basic
function of the controller is to modulate the firing rate of the burner in response to the boiler heat load. The controller monitors
the boiler water temperature through the use of a sensor located in the boiler pressure vessel. The controller compares the boiler
water temperature to the controller’s user defined operating set-point temperature.
An output signal from the microprocessor varies the blower speed through the use of a variable frequency drive (VFD). The gas
valve regulates an appropriate amount of gas flow for a given air flow or blower speed. The user may adjust the operating setpoint
temperature for a given application. In addition, the controller has the ability to change to an alternate set-point through an
external signal for low load conditions (i.e. weekend use, night setback). Outdoor reset is another standard feature, allowing the
boiler operating temperature to vary based on the outdoor ambient temperature. The typical result is a higher seasonal efficiency.
Other features include:
Low Fire
Multiple
Digital
Hold
Set Points
Inputs
2-Stage Operation
Multiple Analog Inputs
Mod Bus Communications
" AUTO TUNE" Optimization Manual Override
B. Set-Up
All of the control parameters have been set at the factory. There are a few parameters called “Process Parameters” that must be
defined by a qualified operator. The table below will help serve as a reference and record when making adjustments.
Parameter
D isplay
Value
Range*
Factory
Setting
User Setting
Setpoint
1
SP1
145-240
180
Setpoint
2
SP2
145-240
0
Digital Setpoint Shift
(optional)
Outside Temperature
(optional)
Pre-definition of External
setpoint (optional)
dSP
145-240
0
TA
SP.E
C onsult Factory
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C onsult Factory
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