Troubleshooting Weak Water Pressure With A Dometic RV Water Heater

Products Featured in This Question

Dometic RV Water Heater - Gas/Electric - Automatic Pilot - 120V - 10,000 Btu - 6 Gallon Tank

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$762.11

Valterra Adjustable Water Regulator for RVs - 15 to 65 psi - Brass

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$98.36

Seaflo Accumulator Tank for RV and Boat Water Pumps - 0.75 Liter

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$44.99

Seaflo Diaphragm Pump for Boats and RVs - Variable Flow - 3 GPM - 55 psi - 12V DC

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$64.99

Question:

I have a 6 gallon dometic hot water heater in our 2019 grand design 337RLS. It has been working just fine and now the hot water will not come out of the Spicket’s. It will build up pressure, then, when you open the valve, it flows for a while and then goes to a small stream . I’ve tried blowing backwards through the hot water line with high-pressure air and pulled the plug and drained the hot water tank. It’s still acts the same. I suspect a plugged line coming out of hot water heater. However, all water going in the system is filtered with a carbon filter and then run through a soft water conditioner. The hot water tank does fill up.

asked by: Bill H

Expert Reply:

If the pressure builds up and then slows down to just a small stream then you most likely are not getting a high enough pressure for the Dometic RV Water Heater # DMC74FR to properly function. It's getting enough water to fill the tank, but not enough to keep it full and handle the demand from the running faucets.

This could be caused by a clog in the line, like you were thinking, or a bad water pump if you aren't using city water. On most RV water pumps there's a little adjuster screw somewhere where you can setting the pressure. It's possible that you just need to adjust it up to help keep up with the demand or it could be a sign that you need to replace the pump.

A typical RV water pump will have a 3.0 gpm rating and usually be around 40-60 psi, just like the Seaflo # SE57FR. Another option to help with water pressure is the inclusion of an accumulator tank, like # SE38FR, which will help build pressure and force out a steadier flow to keep up with demand.

If you're using city water hookups then I recommend using a regulator like part # A01-1117VP so that you can adjust the pressure into the 40-60 psi range to ensure you're at a proper operating psi.