G Series Outdoor Furnaces
www.heatmasterss.com
TROUBLESHOOTING
If the water temp on the control is hot (170-180 F or higher) but the water temp in the supply
line is cool
1. Ensure all lines on the furnace are being used to ensure enough flow and mixing in the fur-
nace tank. If a line is not being used, install a re-circulation loop with a properly sized pump
for your furnace’s required flow rate.
2. Check system for flow. High efficiency boilers require a certain flow rate to dissipate heat into
the water jacket properly.
- Check to ensure all pumps in the system are running and none are turned the wrong way.
- Check filter cartridge for flow blockage (if installed).
- Check for air in the system at the exchanger by bleeding off.
- Check for closed valves to ensure water flow.
3. If no obvious flow issues arise from above system checks, turn off pumps on each line, close
ball valves on the return lines. Remove return line and turn pump on again. Dump water in a
5 gallon bucket and time how fast it fills up. You should be able to calculate flow rate in that
line. Do this for each line coming off of the furnace to calculate furnace flow rate. Below are
required flow rates for each G Series furnace:
G100 - 7 GPM
G200 - 16 GPM
G400 - 25 GPM
If the flow rate does not match what the furnace requires, make sure all lines on the furnace
are being used. A re-circulation line or additional pumps may be required to boost the flow
rate. Have your dealer or a plumber inspect system for possible flow issues or air lock.
If the furnace water and the building supply lines are hot but buildings do not have heat:
1. Check to ensure all pumps in the system are running.
2. Check filter cartridge for flow blockage (if installed).
3. Check for air in the system at the exchanger by bleeding off.
4. Check for closed valves to ensure water flow.
Check Temperature of water exiting the furnace, entering the building being heated and be-
fore and after each heat exchanger. Large temperature drops signal large
consumption of the BTU’s produced by the furnace.
If the furnace overheats:
1. Close all air inlets and doors on the furnace
2. Retrieve as much heat as possible from the system by turning thermostats up and open-
ing windows until furnace cools down.
3. Check that all doors are closing properly and that door gasket is completely sealing.
4. Check that the damper plate is opening and closing properly. It should be completely
closed when the furnace temperature is over 180 F.
5. Check water level.
6. Check to ensure all pumps in the system are running.
If there is a runaway or chimney fire:
1. Make sure the firebox and ash pan doors are tightly closed.
2. Close all combustion air inlets on the furnace.
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