User Guide

Figure 26 Evergreen
®
sequencing options — SMART, PARALLEL or SERIES (examples shown for 3-boiler network)
SERIES Sequencing PARALLEL Sequencing SMART Sequencing
Higher Part-Load Efficiency
Quicker Boiler Response Time
STAGE 1 – Lead boiler modulates up to a maximum of 100% be-
fore turning on the next boiler in the sequence. The STABILIZE
TIME allows time for the boilers to modulate to meet system
demand before turning on additional boilers.
STAGE 1 – Lead boiler modulates up to a maximum of Base
Rate High before turning on the next boiler in the sequence.
The STABILIZE TIME allows time for the boilers to modulate
to meet system demand before turning on additional boilers.
STAGE 1 – Lead boiler modulates up to a low firing rate before
turning on the next boiler in the sequence. The STABILIZE TIME
allows time for the boilers to modulate to meet system demand
before turning on additional boilers.
STAGE 2 – Boiler #2 in sequence ignites and both boilers
modulate to so their combined energy output matches the energy
output of Boiler #1 at 100%. After a short MOD DELAY TIME,
the boilers will be released to modulate.
STAGE 2 – Boiler #2 in sequence ignites and both boilers
modulate to so their combined energy output matches the energy
output of Boiler #1 at Base Rate High. After a short MOD DELAY
TIME, the boilers will be released to modulate.
STAGE 2 – Boiler #2 in sequence ignites and both boilers modu-
late to BASE RATE LOW. After a short MOD DELAY TIME, the
boilers will be released to modulate.
STAGE 3 – Both boilers modulate up to a maximum of 100% be-
fore turning on the next boiler in the sequence. The STABILIZE
TIME allows time for the boilers to modulate to meet system
demand before turning on additional boilers.
STAGE 3 – Both boilers modulate up to a maximum of Base
Rate High before turning on the next boiler in the sequence.
The STABILIZE TIME allows time for the boilers to modulate
to meet system demand before turning on additional boilers.
STAGE 3 – Both boilers modulate up to a low firing rate before
turning on the next boiler in the sequence. The STABILIZE TIME
allows time for the boilers to modulate to meet system demand
before turning on additional boilers.
STAGE 4 – Boiler #3 in sequence ignites and then all boilers
modulate to so their combined energy output matches the energy
output of Boilers #1 and #2 at 100%. After a short MOD DELAY
TIME, the boilers will be released to modulate.
STAGE 4 – Boiler #3 in sequence ignites and then all boilers
modulate to so their combined energy output matches the energy
output of Boilers #1 and #2 at Base Rate High. After a short MOD
DELAY TIME, the boilers will be released to modulate.
STAGE 4 – Boiler #3 in sequence ignites and then all boilers
modulate to BASE RATE LOW. After a short MOD DELAY TIME,
the boilers will be released to modulate.
STAGE 5 – After all available boilers are firing, boilers are release
to modulate up to 100% of rate.
STAGE 5 – After all available boilers are firing, boilers are release
to modulate up to 100% of rate.
STAGE 5 – After all available boilers are firing, boilers are release
to modulate up to 100% of rate.
®
CONDENSING GAS BOILER — 70/110/155 Advanced Manual
Part number 550-100-193/0817
– 50 –
ROTATION AND SEQUENCE (continued)