Laarsen Associates PW, IW, VW warranty III. Water Dripping Firebox

Mighty Therm Volume Water Heater Page 21

II.HEATER IS POUNDING, KNOCKING OR EMITTING STEAM FROM RELIEF VALVES.

Possible Cause	What To Do
A. Low or no water flow.	A. This condition is usually
	caused by lack of adequate
	water flow through heater.
	Check the following:
	1. Is the heater wired into the
	pump circuit so that the heater
	cannot fire 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 flow
	through the heater check to
	see that they are equipped with
	end-switches which shut the
	heater down when the water
	flow through the heater is
	reduced by 70% from full flow.
	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
	inflow of raw water into the
	system. Clean tubes with tube
	cleaning kit. Determine
	hardness. Check water flow,
	replace pump for modified
	flow if necessary.

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 flow through the boiler.

IV. PRESSURE RELIEF VALVES LEAKING INTERMITTENTLY 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
	fittings. Calculate required
	volume of expansion tank in
	relation to system to determine
	if tank is adequate.

V.SOOT IN FLUEWAYS OR IN TUBES, OR NOXIOUS 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
	combustion 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 flue 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 firing at full rate.
E. Heater not fitted 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.