TriangleTube HL-20, Service Technician Manual

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- Is the circulator between the boiler and the water heater properly sized to provide adequate flow for
maximum BTU transfer?
Check component parts
- Is the domestic water thermostat functioning properly? With a electrical voltmeter check for conti-
nuity between terminals C and 1 on the snap-set connection.
Action Item:
1. Disconnect the snap-set connector on the Triangle Tube water heater.
2. Turn the thermostat knob to the highest setting - clockwise to initiate a call for heat.
3. Check for continuity between terminals C and 1 (end connectors on the snap-set). On a call
for heat, these contacts should be in the close position.
4. Continue checking for continuity while turning the thermostat knob to the lowest setting -
counter clockwise to satisfy the call for heat. The contacts should open, breaking the conti-
nuity.
5. If any of these steps fail, replace the thermostat.
6. Reconnect the snap-set.
- Is the thermostat setting too low? If the thermostat setting is too low the boiler may not have the
opportunity to deliver the maximum BTU’s required to completely heat the entire volume of water
stored in the tank.
- During a call for heat by the water heater, does the boiler circulator begin pumping, does the zone
valve open, does the boiler fire? Check every component in the system to ensure they are properly
functioning.
- Check the thermostat sensing bulb size and fit into the drywell. Some older units have a sensing bulb
that is thinner and fits loose inside the drywell. The newer thermostats have a larger bulb which fits
tighter in the drywell allowing better heat transfer for more accurate water temperature sensing.
Action Item:
- If the sensing bulb does not slide into the drywell; remove burrs from top 1 1/2” inside the dry-
well with a 3/8” drill.
Insufficient Hot Water
4
Pipe Size Flow Rate BTU's Transfer
3/4" 3 to 7 gpm 50 to 100 MBH
1" 8 to 15 gpm 100 to 180 MBH
1 1/4" 12 to 25 gpm 160 to 300 MBH
1 1/2" 18 to 35 gpm 200 to 450 MBH
2" 30 to 55 gpm 300 to 650 MBH