64
110332-04 - 2/23
PHTM II
Installation, Operating & Service Instructions
1. Boiler Control
Control simultaneously modulates blower speed
and gas valve position to control firing rate and
sequences up to three pumps to respond to DHW
and CH demands.
2. Flame Supervision/Air-Fuel Ratio Control
Control is a "Gas-Adaptive system" that regulates
air and gas flow mixture by measuring flame
ionization and adjusting gas valve to achieve
target air fuel ratio. This eliminates need to make
throttle screw or offset adjustments. This system is
self-calibrating and continuously maintains air fuel
ratio at desired value.
3. Domestic Hot Water
When there is a DHW demand, system pump
will operate per
P01
setting. Priority protection
is provided to ensure heating system is also
serviced.
4. Central Heat
CH demand is detected by a heating thermostat
call for heat. When CH demand is detected,
control starts boiler pump and modulates firing
rate based on measured supply sensor and CH
setpoint. Control can accept a second heating
thermostat wired to the Aux T'stat input. CH
demands have separate setpoint and maximum
modulation rates.
5. Sensorless Reset
Control system monitors recent firing rate and
burner cycle data to infer current building heat
loss. Target supply water temperature is then
adjusted to match this heat load. No outdoor
sensor mounting or wiring is required. Boost
feature increases operating temperature setpoint
by 10°F (5.6°C) every 20 minutes CH demand
is not satisfied. This process will continue until
heat demand is satisfied (indoor air is at desired
temperature), or CH setpoint is reached. Once
heat demand is satisfied, operating setpoint
reverts to value determined by the Outdoor Reset
settings.
6. Pump Exercise
Connected pumps are automatically run for a 20
second exercise period after not being used for
longer than 7 days. This helps prevent pump rotor
seizing.
7. Pump Air Elimination (Pump Purge)
Pump purge is entered when power is cycled
or when there has been an over temperature
hold. During this state boiler pump cycles on
and off every 5 seconds for two minutes to help
remove air from boiler water piping. This may be
interrupted by pressing the
!
reset
button.
8. Built-in Safety Control
Control includes functions designed to ensure
safe and reliable operation. In addition to flame
supervision, control monitors supply water
temperature, differential water temperature, and
flue temperature safety limits. Boiler modulation
is adjusted when required to help avoid loss
of boiler operation due to exceeding limits.
Additionally, control accepts field installation of
external limits.
9. Fuel Conversion
The conversion from Natural Gas to LP Gas (or
vice versa) is made by changing gas valve setting
and a control parameter change on display.
10. Plug & Play” Multiple Boiler Control Sequencer
When multiple boilers are installed, the Control’s
Sequencer may be used to coordinate and
optimize the operation of up to eight (8) boilers.
Boilers are connected into a “network” by simply
“plugging in” standard ethernet cables into each
boiler’s “Boiler-To-Boiler Communication” RJ45
connection.
11. Priority Demand
Control accepts a call for heat from multiple
places and responds to its "Priority". When more
than one demand is present, higher priority
demand is used to determine active boiler
settings. For example, when DHW has priority,
setpoint, "Diff Above", "Diff Below" and pump
settings are taken from DHW selections. Active
"Priority" is displayed on the Diagnostic Menu,
item "
CO2
", see Table 15-9.
Control System Overview
The control manages all of the following boiler
functions:
15
Operation
(continued)
NOTICE:
This section covers control features available via local display. For additional control features available
via our App, see Extended Features manual available on our website or in our App.
