Velocity Phantom-X Series, Инструкция по установке, эксплуатации и обслуживанию

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X. Operation C. Boiler Protection Features (continued)
C. Boiler Protection Features
1. Supply Water Temperature High Limit
The boiler is equipped with a UL 353 listed boiler
control and UL 1434 listed high limit sensor.
Response to supply temperature is as follows:
• Supply exceeds 190°F (87.7°C) – output (fan
speed) reduced
• Supply exceeds 200°F (93.3°C) – recycle
• Supply exceeds 210°F (98.9°C) – manual reset
hard lockout
Additionally, a soft lockout occurs if the supply
temperature rises to fast (i.e. faster than the degrees
Fahrenheit per second limit).
2. High Limit Differential Temperature Limit
The control monitors temperature difference
between return and supply sensors. Response to
temperature difference is as follows.
• Differential exceeds 43°F (23.9°C) – output (fan
speed) reduced
• Differential exceeds 53°F (29.4°C) –
recycle
• Differential exceeds 63°F (35°C) – shutdown;
automatic restart after temperature difference has
decreased and minimum off time has expired
3. Flue Temperature High Limit
The control monitors flue gas temperature sensor
located in vent outlet at rear of heat exchanger.
Response to flue temperature is as follows:
• Flue exceeds 184°F (84.4°C) – output (fan
speed) is reduced
• Flue exceeds 194°F (90.0°C) – recycle
• Flue exceeds 204°F (95.6°C) – manual reset hard
lockout
4. Flow Switch
The flow switch shuts down the boiler when there
is insufficient water flow in the boiler primary loop.
When water flow is restored to a boiler-specific
minimum value (see Table 24), the flow switch
detects flow and automatically restarts the boiler.
The flow switch is required and is factory provided.
5. Return Temperature Higher Than Supply
Temperature (Inversion Limit)
If return water temperature exceeds supply water
temperature for longer than a limit time delay, the
control shuts down the boiler and delays restart. If
the inverted temperature is detected more than five
times, the boiler shuts down with a hard lockout.
Condition is caused by incorrect supply and return
piping connections.
6. Ignition Failure
The control monitors ignition using a burner mounted
flame sensor. Response on ignition failure is as
follows:
• Size 399: retries five times, then soft lockout for
one hour
• Size 500-800: retries one time, then manual reset
hard lockout
7. Automatic Reset Limit Devices
If any below listed limit opens, the boiler shuts
down and provides an open limit indication. The
boiler will automatically restart once the limit
closes. An external limit control with its own
manual reset button requires pressing external limit
reset button after limit closes even when connected
to Auto Reset External Limit terminals.
• Sump pressure switch – opens if inadequate air
flow is detected during operation
• Condensate float switch – opens if condensate
drain is blocked
• 24V LWCO (if used) – opens if low water
condition is detected
• Device(s) connected to Auto Reset External
Limit terminals
7. Domestic Hot Water (DHW) Setpoint
This is the boiler supply water setpoint upon a DHW call
for heat. Unless an Enviracom thermostat is connected
to the boiler, this set point will always be the fixed
“DHW set point” value entered in the boiler control.
If an Enviracom thermostat is connected, this may also
be the thermostat’s “sleep” or “away” DHW set point.
The optimal value of this setpoint is established based
on the requirements of the indirect water heater.
8. Domestic Hot Water Priority (DHWP)
Some boilers are used primarily for building space
heating, but also provide heat for the domestic hot
water users. When the outdoor temperature is warm,
the outdoor reset setpoint may drop lower than a
desirable domestic hot water temperature. Also, often
it is required to quickly recover the indirect water
heater. When DHWP is enabled, heating circulators
are stopped, the domestic circulator is started and the
domestic hot water setpoint is established in response
to a domestic hot water demand. Priority protection
is provided to allow the heating loop to be serviced
again in the event of an excessively long domestic hot
water call for heat.
9. “Setback” Setpoints
User adjustable Thermostat “Sleep” or “Away” Setback
Setpoints are provided for both Central Heat and
DHW demands. The Setback setpoint is used when the
EnviraCOM thermostat is in “leave” or “sleep” modes.
When setback is “on”, the thermostat setback setpoint
shifts the reset curve to save energy while the home is
in reduced room temperature mode. The Honeywell
VisionPro IAQ (part number TH9421C1004) is a
“setback” EnviraCOM enabled thermostat.