10
The Sequence Reverser accomplishes its tasks and shows the rela-
tive use of each of ten beat stages during the first four days of the
cycle. This is how the work load would be distributed on a boiler with-
out Sequence Reverser. It can be seen the early stages are ON most of
the time and the later stages are OFF most of the time, since they are
used only during heat load peaks. (This analysis assumes hours of use
directly affecting component life. Frequency of on/off operations has
been ignored because of the limited in-rush associated with beating
elements and because of the relative independence of contactor life on
number of operations in the resistive load situations.)
It is clear, without sequence reversing, the early stages would tend
to fail long before the later stages. The sequence reverser essentially
equalizes the relative usages of heating stages. It can be seen, without
the sequence reverser the first heat stage is used approximately twice
as much as it is with the sequence reverser. This means the boiler will
be likely to have its first element failure in half the time without
sequence reverser as compared to the boiler with sequence reverser. In
addition. boilers without sequence reverser will have many failures
spread over a long time while boilers with sequence reversing will
require element changes at roughly the same time. (See wiring dia-
gram on Page 4).
Solid State Progressive Sequencer (See Figure 22)
The solid state progressive sequencer provides accurate electronic
control of multi-stage loads of the type used in Chromalox steam boil-
ers. It features progressive sequencing (first on-first off) which equal-
izes the operating time of each load. This control gives visual indica-
tion of each energized stage by means of integral solid state light emit-
ting diodes. In the event of power interruption all heating elements are
immediately de-energized for safety. When power resumes, the control
will re-stage the loads one at a time. Refer to the diagram for visual
description of progressive sequencing.
PROGRESSIVE SEQUENCING
The solid state sequencer operates on 120 V AC/60 Hz and each
output is relay switched with a load rating of 125 VA at 120 VAC.
OPTIONAL EQUIPMENT FOR CHROMALOX STEAM BOILERS (cont’d.)
MAINTENANCE
Figure 21 – Five Step Sequence Reverser
Figure 22 – Solid State Sequencer
CAUTION:
Hazard of electric shock. Disconnect all
power before working on boiler.
Chromalox Electric Steam Boilers are designed for years of trou-
ble-free performance. To establish a good preventative maintenance
program, we suggest the building maintenance man or engineer famil-
iarize himself with these simple rules:
1.
The use of specific boiler cleaning compounds cannot be recom-
mended. We do recommend that a reputable firm of water treat-
ment engineers be consulted regarding conditioning boiler water.
Proper selection must be made of a compound to prevent damage
to copper sheath heating elements.
2.
The sight glass should be checked daily to ensure the boiler has
adequate water.
3.
A monthly inspection should be made of the internal wiring. All
electrical connections should be checked for lightness.
4.
A check for water or steam leaks should also be made and any
loose fittings immediately tightened.
5.
If boiler is equipped with a Solid State Auxiliary Low Water
Cutoff, every four months the probe should be checked for
deposits and cleaned, if necessary. This is accomplished by remov-
ing the inspection plate, removing the probe (with a standard
sparkplug wrench) cleaning and replacing.
Note: The system will not operate if the boiler is using distilled,
demineralized or deionized water.
At the same time, one of the bottom heating elements should be
removed. If scale has begun to form, all elements should be
cleaned and boiler drained and flushed.
6. IMPORTANT:
The Manufacturers' Data Report enclosed within
the instruction sheet is very important and must be put in a safe
place. You may be called upon to produce it by a State agency.