Instruction manual

62
SECTION XII: OPERATING (CONTINUED)
g. Start Temperature (t_)
The amount of “Heat available” is calculated by
taking the difference between measured boiler
water temperature and the Start Temperature
setting. Useful “Heat Available” is dependent
on the type of heating emitter installed in the
home. Heat emitters require a certain minimum
temperature to operate effectively. Our default
settings reect cast iron radiators. Fan Coils
may require a start temperature setting of 180°F
or 160°F before providing heat to the home. The
Start Temperature has a factory setting of 140°F
and is eld adjustable between 140°F and 180°F.
h. Priority Time (Pt_)
When the Priority Time parameter is set to “on”
and Domestic Hot Water (DHW) call for heat is
“on” the DHW demand will take “Priority” over
home heating demand and the system circulator
will be forced “off”. Priority Time ends and
the system circulator is released to service home
heating demand when Domestic Hot Water call
for heat is over. When Priority Time parameter
is set to “Off” the DHW call for heat does not
force “off” the system circulator. The Priority
Time has a factory setting of “On” and is eld
adjustable between “On” and “Off” Refer to
Table 7A.
i. "ZC" and "ZR" Terminal Function (ZC_)
The boiler control allows conguration of the
"ZC" output functionality to help the V8H
integrate into each installation more effectively.
The "ZC" output can be connected to a domestic
hot water circulator or a second heating zone
circulator or be used to enable pumps in a warm
start application. These applications are selected
as follows:
i. When ZC_ is set equal to Domestic Hot
Water Demand (dh)
When there is an Indirect Water Heater
(IWH) the boiler control provides a “ZR”
input terminal for the IWH Aquastat
and “ZC” output terminal for the DHW
Circulator. When there is a DHW call
for heat, the System Circulator is “forced
off”, the DHW Circulator terminal is
energized and the circulator pre-purge time
delay control logic is bypassed to allow
the boiler to re without delay. When
DHW demand ends the System Circulator
“force off” is removed, the circulator can
respond normally, and the DHW Circulator
is de-energized. The DHW call for heat
is detected by a voltage on to the "ZR"
terminal. When a Priority Time parameter
is set to “off” the System Circulator is not
forced off for a DHW call for heat. Refer to
Table 7A.
When an Outdoor Air Reset Option Card is
installed and there is a DHW call for heat
there is an adjustable DHW Temperature
Setpoint and Priority Timer included. Refer
to Table 7B.
Call for Heat Circulator Status
T-T
Input
ZR
Input
Priority
Time
(Pt_)
System
Circulator
Output
DHW
Circulator
ZC Output
on off On on off
on on On off on
off on On off on
on off OFF on off
on on OFF on on
off on OFF off on
TABLE 7A: DOMESTIC HOT WATER DEMAND,
(PARAMETER ZC_= DH)
TABLE 7B: DOMESTIC HOT WATER DEMAND,
(PARAMETER ZC_= DH)
Outdoor Air Reset Option Card Installed
Call for
Heat
Outdoor Air Reset
Option Card
P/N 102294-01
Circulator
Status
T-T
Input
ZR
Input
DHW
Input
Priority
time
Priority
Time
Expired?
C1
Output
ZC
Output
off -- off > 0 no off off
on -- off > 0 no on off
on -- on > 0 no off on
on -- on > 0 yes on on
on -- on = 0 no on on
off -- on = 0 no off on
Call for
Heat
ZC and ZR
Terminal
Function
(ZC_)
Boiler
Temp.
Boiler Status,
(B1 Output)
TT= on -- < 140 Start with no delay
TT = on -- >140 Start after 2 minute delay
ZR = on ZC_ = ZR <140 Start with no delay
ZR = on ZC_ = ZR >140 Start after 2 minute delay
ZR = on ZC_ = DH <140 Start with no delay
ZR = on ZC_ = DH >140 Start with no delay
TABLE 6: CIRCULATOR PRE-PURGE TIME EXAMPLE,
PARAMETER PP_= 2 MINUTES