Part number 550-100-305/0916
57
AquaBalance
TM
W
ALL
M
OUNT
GAS
-
FIRED
WATER
BOILER
— C
OMBI
Boiler Manual
27
Startup
Use the correct amount of antifreeze
1. Determine the freezing temperature needed (to protect
against lowest likely temperature the system water will en-
counter).
2. Find the antifreeze concentration by volume needed for this
temperature from the antifreeze manufacturer’s data on the
antifreeze container.
3. Add up the volume (gallons) of all system piping and com-
ponents, including the expansion tank and boiler.
a. Boiler water content is listed in Figure 130, page 98.
b. Remember to include expansion tank water content.
4. Multiply this volume by the (percent) antifreeze needed to
find the number of gallons of antifreeze to add.
Fill and test water system
1. Fill system only after ensuring the water meets the require-
ments of this manual.
2. Close manual and automatic air vents and boiler drain valve.
3. Fill to correct system pressure. Correct pressure will vary
with each application.
a. Typical cold water for a residential system is 12 psi mini-
mum fill pressure.
Boiler water pressure switch is set for 9 psi (±2)
minimum pressure. A low water pressure will give
“
F37
” fault code.
b. Pressure will rise when boiler is turned on and system
water temperature increases. Operating pressure must
never exceed 25 PSIG.
4. At initial fill and during boiler startup and testing, check
system thoroughly for any leaks. Repair all leaks before pro-
ceeding further.
Eliminate all system leaks. Continual fresh make-up
water will reduce boiler life. Minerals can build up
in the heat exchanger, reducing heat transfer, over-
heating heat exchanger, and causing heat exchanger
failure.
Purge air from water system
1. Connect a hose to the drain valve (see drain valves, item 10,
in piping diagrams beginning on page 11). Route hose to an
area where water can drain and be seen.
2. Close the boiler or system isolation valve between the drain
valve and fill connection to the system.
3. Close zone isolation valves.
4. Open quick-fill valve on cold water make-up line.
5. Open drain valve.
6. One zone at a time, open the isolation valves. Allow water
to run through the zone, pushing out the air. Run until
no noticeable air flow is present. Close the zone isolation
valves and proceed with the next zone. Follow this proce-
dure until all zones are purged. Follow the same procedure
to purge air from the boiler and its internal piping.
7. Close the quick-fill water valve and drain valve and remove
the hose. Open all isolation valves. Watch that system pressure
rises to correct cold-fill pressure.
Clean system to remove sediment
1. You must thoroughly flush the system (without boiler
connected) to remove sediment. The high-efficiency heat
exchanger can be damaged by buildup or corrosion due to
sediment.
If the system needs to be cleaned, use only Sentinel
X400 cleaner, available from Weil-McLain. See
Figure 124, page 93 for information. Follow instruc-
tions supplied with the X400 cleaner and cleaning
instructions on page 88. For zoned systems, flush
each zone separately through a purge valve. (If
purge valves and isolation valves are not already
installed, install them to properly clean the system).
2. Flush system until water runs clean and you are sure piping
is free of sediment.
Do not use petroleum-based cleaning or seal-
ing compounds in boiler system. Damage to
elastomer seals and gaskets in system could oc-
cur, resulting in substantial property damage.
Before filling the boiler and system with water,
verify the following. Boiler corrosion can occur.
Failure to comply could result in boiler failure
or unreliable operation.
Water chemistry
7ATERP(BETWEENAND
1. Maintain boiler water pH between 7.0 and 8.5. Check with
litmus paper or have chemically analyzed by water treatment
company.
2. If pH differs from above, consult local water treatment com-
pany for treatment needed.
Hardness less than 7 grains
1. Consult local water treatment companies for unusually hard
water areas (above 7 grains hardness).
Chloride concentration must be
,%334(!.PPM
1. Filling with chlorinated fresh water should be acceptable since
drinking water chloride levels are typically less than 5 ppm.
2. Do not use the boiler to directly heat swimming pool or spa
water.
3. Do not fill boiler or operate with water containing chloride
in excess of 50 ppm.
Verify that the water chemistry meets the limita-
tions and requirements of all other equipment in
the system.
Antifreeze
1. Use only antifreeze listed by Weil-McLain as suitable for
use with Combi boilers. See Figure 124, page 93 for infor-
mation.
2. See Replacement parts at the end of this manual for
part numbers to obtain antifreeze through a Weil-McLain
distributor.
