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BRADFORD WHITE
Page 18
B4 Volume Water Heater Page 19
II. HEATER IS POUNDING, KNOCKING OR EMIT-
TING STEAM FROM RELIEF VALVES.
Possible Cause What To Do
A. Low or no water ow. A.This condition is usually
caused by lack of adequate
water ow through heater.
Check the following:
1. Is the heater wired into the
pump circuit so that the heater
cannot re unless the pump is
running?
2. Check to see that all valves
in system are open to be
sure that water can circulate
through the heater and the
system.
3. If the system has automatic
water valves (2-way or 3-way)
that can cut off the water ow
through the heater check to
see that they are equipped with
end-switches which shut the
heater down when the water
ow through the heater is
reduced by 70% from full ow.
4. Examine pump for clogged
impeller.
B. Low or no system pressure. B. Clean strainer in pressure
reducing valve. Look for closed
valve water line or a leak in the
system.
C.Clogged “Y” strainer. C. Remove strainer element and
clean screen.
D.Debris from system piping D.Remove header covers.
is blocking tubes. Examine all tubes and
waterways. Use new gaskets
when reassembling. Clean
out tubes.
E. Scale has formed in tubes. E. This is always caused by the
inow of raw water into the
system. Clean tubes with tube
cleaning kit. Determine
hardness. Check water ow,
replace pump for modied
ow if necessary.
IV. PRESSURE RELIEF VALVES LEAKING INTER-
MITTENTLY OR STEADILY.
Possible Cause What To Do
A.Static pressure in system A. Calculate height of water in
exceeds setting of relief valve. system above heater. Install
new valve with psi setting 25%
above required static system
working pressure. Do not
exceed 160 psi.
B. Expansion tank is water- B. Drain expansion tank, then
logged (if installed). reopen it to the system. Look
for leaks in expansion tank
or ttings. Calculate required
volume of expansion tank in
relation to system to determine
if tank is adequate.
V. SOOT IN FLUEWAYS OR IN TUBES, OR NOX-
IOUS FUMES INDICATIVE OF BAD COMBUSTION.
Possible Cause What To Do
A. Combustion air supply to A. Check air supply opening.
heater room is inadequate. Look for debris in screen or
louvre which covers combus-
tion air opening, or for material
blocking the opening.
B. Stack or vent is blocked or B. Look for blocked stack and
restrictive. excessive number of elbows in
stack or excessive length of
horizontal runs.
C.Severe down draft is causing C.Check for (1) proper vent cap
spillage of ue products into on stack; (2) adequate height
room. of stack above roof;
(3) equipment exhausting air
from inside of building; and
(4) proper installation of draft
diverter.
D.Gas pressure to burners is D.Check gas pressure with
excessive. nanometer, and adjust with
heater ring at full rate.
E. Heater not tted for the fuel E. See nameplate for correct fuel.
supplied.
F. Heater installed at high F. Installations at altitudes in
altitude without proper excess of 2000 ft. above sea
derating. level are subject to jurisdiction
of the local inspection
authorities.
III. WATER DRIPPING
IN FIREBOX.
Possible Cause What To Do
Tube in heat exchanger has A tube failure is almost always
overheated and ruptured. caused by (a) scale formation
in the tube or (b) inadequate
water ow through the heater.