34000 Autry Street, Livonia, MI 48150 • 800.968.5530 • Fax 734.419.0209 • www.hamiltonengineering.com • LIT91195 REV 11/2020
INTRODUCTION
All high eciency condensing
appliances will require more
maintenance (cleaning) than their
non-condensing counterparts. Failure
to properly maintain these units may
result in damage to the appliance that is
not covered under warranty. Failure to
follow all of the instructions contained in
this manual may also cause premature
product failure that may not be covered
under warranty.
Normal descaling can be accomplished
in two hours per unit, and (except under
the most severe conditions) should not
require more than four hours. DS40
FERNOX is the descaling solution
recommended by our stainless steel
manufacturer.
WHEN TO CLEAN
In some extreme applications (hard
water and/or higher than normal
operating temperatures) the heat
exchanger may require chemical
cleaning. If you are experiencing H11
lockouts that cannot be attributed to
pump related problems or remedied by
back flushing the heater with city water
pressure, chemical cleaning of the heater
is likely your maintenance solution.
Additionally, if your heating boiler or
water heater is experiencing ‘popping’,
‘banging’, or ‘knocking’ noise and
shaking as a result of the water boiling
as it circulates through the heat
exchanger and it can not be attributed to
the circulating pump, chemical cleaning
of the heat exchanger may be required.
PLEASE NOTE: If any of these noises
are heard, the appliance should not be
operated until the cause is identified
and resolved!
Chemical cleaning of the heat exchanger
should only be done at the direction of
Hamilton Engineering Company, Inc.
Failure to follow the prescribed cleaning
procedure will result in voiding any
warranty of the heat exchanger.
DESCALING SOLUTION
DS40 is a highly eective, heat
activated descaling solution. It must
be heated to 160°–180°F to clean
eciently! Follow instructions listed
below.
Kit (P/N HEX 61102) includes 3.3 lb.
(1.5 kg) container of DS40 and a pack of
neutralizer, which is used to neutralize
the used cleaning solution before
discarding it. 3.3 lb (1.5 kg) will treat up
to 20 gallons of water.
MIX RATIO:
HW299–HW599 (Duo): 1/2 (~1.6 lb.) of
container per 8–10 gallons of hot water.
Add hot water, agitate until dissolved.
For additional information, consult
manual inside box or go to
www.fernox.com
DESCALING PROCEDURE
(using DS40 cleaning kit)
1. Shut o gas at appliance
2. Shut o water to and from
appliance (isolate via ball valves);
drain water
NOTE: In some cases, you may want
positive isolation of the cleaning
solution from the rest of the system.
Breaking the unions on the water lines,
removing the nipples and fittings from
the manifolds, and then capping the
manifold openings will accomplish
isolation. This would be done between
steps 2 & 3.
3. Attach a hose to the drain on the
ball valve below the pump if so
equipped. If your heater does not
have a drain, remover the pump
and attach a water spigot to a
flange and install where the
pump was.
4. Attach female end of hose to the
adapter; the termination end of
the hose will go into the acid
solution bucket.
5. Attach the female end of the other
hose to the drain valve connection
on the outlet side of boiler, then
attach the opposite end to the
chemical pump.
6. Pour water into plastic, chemical
and heat resistant 5–10 gallon
container (depending on size of
appliance). Add cleaning solution.
See ‘Descaling Solution’ above for
required amounts. Prime the pump.
7. Turn on pump and circulate
solution (this is the reverse of
normal flow).
8. On models HW 299.2, HW 399.2 &
HW 599.2 you will need to change
parameters S14 and S15 from 1 to 0.
This will allow you to fire the heater
in service mode without tripping
faults. See the next line for .3
models.
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