Suggested Outdoor Reset Parameter Settings; Supply Temperature Boost; Boiler Circulator; Freeze Protection/External Controls (Interlocks) - Weil-McLain ULTRA ULTRA-105 Service Manual

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GAS FIRED WATER BOILER SERIES
Operating information
Outdoor reset operation, if used
Setpoint temperature with outdoor reset
All Ultra boilers are shipped with an outdoor temperature sensor.
When this sensor is installed (low voltage terminal strip termi-
nals 1 and 2), the control module regulates target outlet water
temperature based on outside temperature.
See detailed discussion of outdoor reset parameters
beginning on page 44.

Suggested outdoor reset parameter settings

1. Parameter 4, T1 — Set to the required supply water
temperature when outdoor temperature is at or below
ODT (outdoor design temperature).
2. Parameter 5, T1 — Set equal to the required room
temperature for the building.
3. Parameter 6, T4
temperature.
4. Parameter 7, T4
perature for the building (typically 60 to 70°F).
Install a summer/winter switch, if desired, to disable the boiler
(space heating) circulator during non-heating months. Connect
switch across the outdoor sensor terminals. When switch closes,
the boiler circulator is disabled and the boiler operates only on
call for DHW heating.

Supply temperature boost

In outdoor reset operation (outdoor sensor connected), the Ultra
control module automatically increases the target outlet water
temperature if a call for heat exceeds 10 minutes. At each 10 min-
utes of a continuous call for heat, the control module increases the
target temperature by 18°F. The module will continue increasing
target temperature until it reaches the value set in parameter 4.
When the call for heat ends while target temperature is "boosted,"
the target temperature drops about 2°F for each minute the
thermostat is open.
Purpose of boost — If the target temperature happens to be too
low, the control "boosts" the target temperature until the supply
water meets the system's needs.
10
— Set to the ODT outdoor design
— Set to the balance point tem-
—
1 & 2
(continued)
DHW operation, if used
PhD Control Module allows connection of a DHW
The
aquastat to low voltage terminal strip terminals 3 and 4. When the
DHW aquastat calls for heat, the module shuts down the boiler
circulator, activates the DHW circulator and immediately sets
target outlet water temperature to 190°F. This provides automatic
priority heat allocation to the indirect water heater for maximum
response and recovery. The DHW circulator continues for 30 sec-
onds after the heating cycle to deliver the most possible heat.

Boiler circulator

Each Ultra boiler is shipped with a circulator. The circulator has
sufficient head to handle boiler pressure drop plus reasonable
pressure drop in the connecting piping. See Ultra Boiler Manual
for piping and flow rate information. The control module internal
relay contact is suitable for handling only the boiler circulator
provided. Do not wire additional pumps in parallel with the
boiler circulator. To operate a system circulator when the boiler
circulator operates, see pages 4 and 5 for wiring required.
Freeze protection
DO NOT install the boiler in a room likely to freeze.
The following integral feature of the Ultra control module pro-
vides some protection for the boiler only — not for the system.
The Ultra control module provides freeze-up protection
as follows when the boiler water temperature drops below
45°F:
Below 45°F, the boiler circulator operates constantly.
Below 37°F, the boiler turns on at low fire.
Boiler and circulator turn off if boiler water temperature
rises above 50°F.
This feature of the Ultra control module does not
eliminate the possibility of freezing. The installation
must still use recognized design, installation and
maintenance practice to prevent freeze potential
for the boiler and system.
External controls (interlocks)
External limit controls wired between low voltage terminal strip
terminals 6 and 7 will cause the boiler to shut down in soft lock-
out when they open. Remove the factory jumper between these
terminals when using.
External limit control wired between low voltage terminal strip
terminals 6 and 8 will cause the boiler to hard lockout (requiring
manual reset of the electronic display RESET button). Remove
the factory jumper between these terminals when using.
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(if used)
Part number 550-100-029/0810