9
Section 4
Troubleshooting
Observations regarding any problems should be recorded.
1. Does the problem present itself during no flow, low
flow, or high flow conditions, etc?
2. High temperature or low temperature? Note the
RediHeat is designed to prevent high temperature
failures, however, recirculation system failures may
lead to overtemperature situations during low flow
conditions.
3. Unsteady temperature?
4. Is the unit new or what is length of service?
5. What is the local water hardness?
6. Is the problem repeatable, sporadic?
The first step in resolving a problem with a RediHeat water
heater system should be to determine the source of the
problem:
•
The recirculation system
•
The RediHeat blending valve
•
The RediHeat heat exchanger
1. Check the position of the water outlet temperature
gauge. Has it been installed according to the
recommended Piping & Instrumentation Diagram?
The gauge should be downstream relative to the point
where the recirculated water returns to the unit.
2. For facilities with recirculation systems, the circulating
pump should be turned off to start the troubleshooting
analysis.
Water Temperature Is Too High
1. Has inlet water temperature changed since the valve
temperature setting was adjusted?
2. Is the RediHeat temperature adjustment set correctly?
3. Has steam pressure changed since the RediHeat
temperature was adjusted?
4. If fitted with a recirculation system, turn the circulating
pump off. If the problem is eliminated, the trouble is
with the recirculation system.
5. For a new installation with a recirculation loop, check
the setting of the thermostatic valve. The thermostatic
element setting should be approximately 10°F below
the normal operating temperature of the RediHeat. For
example, if 120°F is the desired loop temperature, the
thermostatic element should be set for 110°F.
6. If the problem developed in an existing system, the
thermostatic element should be replaced.
See Section 5 “Recirculation Systems” for thermostatic
diverting valve piping instructions. Because this valve is
used in a non-typical manner, it is important to install the
valve as recommended in this manual.
Water Temperature Is Too Low
1. Is the problem in the RediHeat valve or the RediHeat
heat exchanger? The easiest method to answer this
question is to check the temperature of the pipe which
runs from the heat exchanger to the blending valve. At
low flows and when the unit is idle, this pipe should
be at a temperature about 200°F. At higher flow rates,
check the surface temperature of the pipe which
should remain above 150°F. If this pipe goes cold when
water demand increases, the problem lies in the heat
exchanger. Otherwise, the source of the problem is in
the RediHeat blending valve.
Heat Exchanger Is Source of Problem
1. Has air been vented from the shell side of the heat
exchanger?
2. Is steam supply at constant pressure? During high
demand?
3. Is the condensate drain trap functioning correctly?
4. Is the coil fouled due to hard water?
RediHeat Blending Valve Is Source of Problem
1. Is temperature adjustment correct?
2. Disassemble valve - is the plug stuck in the open
position?
3. Is the seal plate assembly and gasket in need of repair?
Restricted Water Flow
1. Is the valve diaphragm ruptured?
2. Is the sensing tube plugged?
3. Are there any restrictions in the water piping?
