Rheem Marathon Thermal MTS105200 - Manual (Page 12)

12
Before You Call For Service…
Troubleshooting Tips
Save time and money! Review the chart on this page first and you may not need to call for
service.
Problem Possible Causes What to Do
Rumbling noise
upon start-­up Normal settling of internal compo-­
nents. z No action required.
Relief valve
producing popping
noise or draining Pressure build up caused by thermal
expansion in a closed system. z This is an unacceptable condition and
must be corrected. Contact the water
supplier or plumbing contractor on how
to correct this. Do not plug the relief
valve outlet.