Lochinvar 751 - 2001 사용자 설명서

        

Installation & Operation Manual

The Crest uses an advanced stainless steel heat exchanger 
and electronic control module that allows fully condensing 
operation.  The blower pulls in air and pushes flue products 
out of the boiler through the heat exchanger and flue piping.  
The control module regulates blower speed to control the 
boiler firing rate.  The gas valves sense the amount of air 
flowing into the boiler and allow only the right amount of 
gas to flow.

The Crest boiler is equipped with a SMART TOUCH control 
module.  The SMART TOUCH control module receives 
inputs from boiler sensors and external devices.  The control 
module activates and controls the blower and gas valves 
to regulate heat input and switches the boiler, Hot Water 
Generator (HW), and system pumps on and off as needed.  
The user programs the control module to meet system needs 
by adjusting control parameters.  These parameters set 
operating temperatures and boiler operating modes.  

This input tells the boiler to provide water for space heating.

This input tells the boiler to provide water for heating an 
indirect HW tank.

The Crest can be controlled by a Building Management 
System (BMS) using a 0 - 10 VDC signal.  The control can be 
configured by the installer to use this signal to either control 
set point or firing rate.

When a variable speed system pump is used, and there is a 
0 - 10V signal available from the pump speed control, this 
signal may be connected to the boiler.  Doing so will allow 
the boiler to anticipate changes in the BTU’s needed by the 
system as the system flow changes, and therefore, help the 
boiler to maintain the desired system temperature.  Connect 
the - input terminal to the COM or - output terminal on the 
pump speed control, and the + input terminal to the 0 - 10V 
or + output terminal on the pump speed control.  Note that 
the voltage on these inputs must never go below ground.

The SMART TOUCH control allows the connection of a HW 
thermostat or tank sensor to the low voltage connection board.  
When a tank sensor is connected, the HW thermostat input is 
ignored.  When a boiler is programmed for HW Normal Mode, 
the maximum firing rate can be limited to match the input 
rating of the indirect tank coil.

If a HW call for heat is received while a space heating call is in 
progress, and the HW is in Normal Mode, the control will start 
the HW pump and shut the boiler pump off. The system pump 
will remain on. For stand-alone boilers, if the space heating call 
is still active while the HW call is in operation, the control will 
wait for 30 minutes (time adjustable by installer) then it will 
switch back to the space heating demand. There is a timer to 
switch from space heating to HW and a timer to switch from 
HW to space heating. The control will switch back and forth 
until one of the heat demands end. This function does not apply 
to cascade systems.

The control module is programmed to use the outlet sensor 
as the control sensor by default.  If a system supply sensor 
is connected, the control automatically uses it as the control 
sensor. The control module may be programmed to use the inlet 
sensor as the control sensor instead.  In this case, the control 
will use the system return sensor if it is connected.

After a space heating demand has been satisfied, the control will 
delay the next space heating call for a set time period (time is 
adjustable by the installer).  The time delay will be bypassed if 
the inlet water temperature drops too far during the delay.

When a space heating call for heat starts and no HW call is on, 
the boiler pump is turned on.  The system pump will turn on 
also if it is programmed to do so.  If a HW call for heat is on, the 
boiler pump will wait to turn on until just before the HW pump 
turns off.  After the space heating call for heat ends, the boiler 
pump will run for an additional period of time.

When a HW call for heat starts, the HW pump is turned on.  If 
a space heating call for heat is on, the boiler pump will turn off 
a few seconds after the HW pump turns on.

When the boiler needs to control combustion air louvers, 
connect a 24 VAC louver relay to the two (2) Louver Relay 
terminals.  Connect the Louver End Switch to the Louver 
Proving Switch input on the Low Voltage Connection Board.

The Crest is capable of modulating its firing rate from a 
minimum of 4-6% (depending on model) to a maximum of 
100%.  The firing rate is dictated by the call for heat (i.e., space 
heating or hot water generation), the heating load, ramp delay 
(if enabled), and various other temperature limitations.