CWH companion water heater — Product Manual
Water heater filling and start-up
The installation and water chemistry must meet the
requirements below. Failure to comply could result in
damage to the water heater, causing possible severe
personal injury, death or substantial property damage.
Boiler water restrictions
• Thoroughly flush the boiler system (without water heater con-
nected) to remove sediment.
• The water heater heat exchanger can be damaged by build-up or
corrosion due to sediment.
• Boiler water (including additives) must be practically non-toxic,
having toxicity rating or class of 1, as listed in Clinical Toxicology
of Commercial Products.
• If antifreeze is used in boiler system:
• Local codes may require a backflow preventer on cold water
supply line.
• Use only antifreeze products listed in the WM97+ Boiler
manual.
• Follow WM97+ Boiler manual instructions for antifreeze
usage.
Filling the domestic water tank
1. The CWH tank contains domestic water. The CWH heat exchanger
coil water is circulated from and to the boiler with the CWH circulator.
2. Fill the CWH tank and domestic water system with fresh domestic
water that meets the chemistry requirements below.
a. Hardness — less than 6 grains/gal.
b. pH — above 6 and less than 8.
c. Chlorides — less than 200 ppm.
3. A water softener in the domestic water system is acceptable. A water
softener is recommended if water hardness may exceed the limit above.
4. Do not exceed a fill pressure of 70 PSIG.
When the water supply pressure is higher than 70 PSIG, make
sure that a pressure-reducing valve is installed on the cold
water supply line to prevent leakage from the T&P relief valve.
A thermal expansion tank is also required.
5. Vent the piping as necessary to remove any trapped air.
Start-up checklist
Verify that T&P relief valve is properly installed
and piped as directed in this manual and per local
code requirements.
Verify that the CWH (boiler and DHW) and boiler
piping are complete and that the system is filled
with water and pressurized.
Verify that all air has been bled from both domestic
and boiler water systems.
Check all fittings and piping for leaks.
Verify that all wiring is installed correctly.
Set mixing valve temperature as described in the
mixing valve instruction manual supplied with the
mixing valve kit.
Start boiler according to the WM97+ Boiler
Manual
and to the control setup information in
this manual.
WM97+ control set-up
Quick set-up — see “CWH Performance Mode
quick set-up” on page 22 for set-up using default
settings for water heater operation. This will cover
most applications.
Customizing CWH operation — see “WM97+
Control settings — Advanced” on page 24. This
page and the pages following provide details about
control operation, menu navigation and methods
for customizing the default operating parameters.
Verify operation
Verify that the boiler and water heater are operating
correctly, per WM97+ Boiler manual.
Homeowner instruction
Review the following sections with the homeowner
or system operator:
• WM97+ Boiler/CWH User’s Informa-
tion Manual
(includes information for setting
WM97+ control for CWH)
• Adjusting Water Heater Temperature
• CWH Water Heater Maintenance
Part number 635-500-156/0113
21
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