Service Manual

ManualsBrandsLochinvar ManualsBoilers406,000 BTU Output Knight XL High Efficiency Boiler

1 Service

Service Manual

1 Service (continued)

H: Control modes

SH controlling sensor

The SH controlling sensor parameter selects the sensor the

control will use to regulate the boiler firing rate. This

parameter is adjustable by the installer by accessing

parameter H1. The sensor selections are as follows: The

outlet sensor regulates the firing rate based on the outlet

water temperature of the boiler and the inlet sensor regulates

the firing rate based on the inlet water temperature of the

boiler. If the outlet sensor is selected, and the optional system

supply sensor is connected, the control will regulate the firing

rate based on the system supply sensor temperature. The

default sensor is the Outlet Sensor.

SH source

The SH source parameter selects the method used to control

the modulation of the boiler. This parameter is adjustable by

the installer by accessing parameter H2. The control methods

are as follows:

1 - Thermostat. The control modulates the boiler based on

the user set point and the temperature of the selected

controlling sensor.

2 - BMS (Building Management System). The control

modulates the boiler based on the 0 - 10 VDC signal delivered

to the appropriate terminals on the connection board. When

BMS is selected additional parameters for BMS operation

may need to be adjusted. These can only be accessed by the

optional PC software. See the Knight Smart System PC

Program Instructions Manual for additional BMS parameter

information.

3 - Cascade. The boiler is part of a group of boilers sequenced

together. The designated Leader boiler determines the total

output needed from the group based on the set point and

controlling sensor reading. It assigns portions of this output

to itself (Leader) and the Member boilers. When Cascade is

selected, each boiler in the group requires a unique address

(see below). The default control is Thermostat.

Boiler cascade address

The boiler designated as the Leader needs to be programmed

with address 0. All the Member boilers require addresses

from 1 to 7, and the addresses must be different for each

Member. The addresses can be in any order, regardless of the

order in which the units are wired together. This parameter

is adjustable by the installer by accessing parameter H3. The

outdoor air (if used) and system supply sensor must be

connected to the Leader boiler. The default address is 1.

Max. cascade set point

This parameter determines the set point used by the

individual boilers in a Cascade. When a boiler is commanded

to fire by the Leader boiler, it will attempt to achieve this

temperature at its outlet. The Leader boiler will limit the

modulation of the last boiler to fire in order to hold the

temperature at the system supply sensor to the user set point.

If any of the boiler outlet temperatures reach the max.

cascade set point, the boiler will then modulate down on its

own in order to keep its outlet temperature within the max.

cascade set point. Therefore, this parameter can be used to

limit the outlet temperatures of all the boilers in a Cascade.

Note that this parameter does not apply when the boiler is

heating an indirect DHW tank. This parameter is adjustable

by the installer by accessing parameter H4. The default max.

cascade set point is 185°F (85°C).

Figure 1-2 Ramp Delay Interval

% RATE

RAMP 6

RAMP 5

RAMP 4

RAMP 3

RAMP 2

RAMP 1

CALL

FOR

HEAT

TIME

MINUTES