My tankless water heater (Paloma) makes a rumbling noise when the shower is set to "warm"?

by Water Heaters on April 26, 2010

The shower temp control is a single knob type. The entire system is new construction. The shower at issue is closest to the heater system which is in the attic.
Water supply is all 1/2" copper. No other noises occur from other two bathrooms (or kitchen) under similar conditions.


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{ 2 comments… read them below or add one }

Jamie T April 26, 2010 at 5:08 am

Paloma tank less water heaters are made in Japan, but they also go by the name Rheem from Montgomery Al. There could be a number of things causing this problem. The water heater keeps close tabs on the temp of the water coming in the unit, the temp of the water leaving the unit and the temp asked for by the source of demand. Paloma make a good heater that can keep up with high demands, one of the best made. But when you need just a little bit of hot water you can run into issues. The best thing to do is call tech support on your manual, have your serial number ready. They will walk you through troubleshooting from your remote panel. They can tell you the temp of water, gal per minute, and a bunch of other stuff. Last year there was also a recall on the automatic flut. Ask about that as well. A quick fix may be changing the shower head to one that allow more Gal per minute. If not, good luck with tech support. Tell Ronni I said hi.

gametom43 April 26, 2010 at 5:08 am

It sounds like you have pex or a similar plastic water supply piping in your new house. The pipe is held in place by clips in the wall. When you turn on warm or hot water…the pipe expands and slips against the clip in the wall creating the rumbling noise.

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