TriangleTube HL-20, Service Technician Manual

Page: 8 / 21

- What is the location of the thermostat bulb? A bulb inserted completely at the bottom of the drywell
will initiate a quicker response for a call for heat. This is typically the position of the bulb required
for applications in which there are large draws of domestic water.
- Remove and examine the dip tube located in the cold water inlet. Replace if damaged. A broken or
melted dip tube will cause the cold water to discharge across the top of the tank, thus short cycling the
water heater.
Check the operating temperature of the boiler
- If possible increase the boiler operating temperature to 180ºF or 200ºF.
- Maintain a minimal temperature in the boiler during non-heating seasons. A boiler typically has a
higher standby loss than the indirect water heater. After a long standby period the colder boiler may
absorb the stored energy within the water heater during the initial call for heat.
Check location of flow control devices
- Lab tests have shown that during long standby periods the boiler piping can act as a thermal siphon
and draw stored heat from the domestic water. Locate flow control devices (zone valve, spring check
valves...) or heat trap loops in the boiler piping close to the water heater. Insulate all boiler piping to
and from the water heater.
Check for air in the system
- An air bound water heater or boiler will not circulate system water properly, resulting in a lack of heat
transfer.
Clean the boiler system
- A dirty boiler system can cause deposits to form on the outer wall of the inner tank, which insulates
the tank, affecting the heat transfer. Clean the boiler system per the boiler’s manufacturer’s instruc-
tions.
Action Item:
- Install a strainer in the boiler piping on older installations or for systems prone to becoming
dirty.
Insufficient Hot Water
5