Rinnai Tankless Recirculation Pump Noise!
We live in a 1950 L-shaped ranch house where the utility room is in the back. With our old hot water tank, we had to wait almost five minutes for hot water to reach the kitchen and farthest bathroom and even then it was just warm at best. So when the old tank needed to be replaced, we switched to a gas-fired Rinnai tankless RUR 199i with built-in recirculation pump. It's wonderful to have instant hot water everywhere, but we were not prepared for the noise of the pump. We are home all day, so the pump timer is set for 8 a. m. to 10 p. m. When it operates (which is fairly often), we hear a noise I can best describe as like a motor running. Like when the refrigerator runs, but louder and more noticeable. It is not vibration in the pipes, as has been discussed in other online forums, and we don't hear it elsewhere in the house. Our bedroom and my office are located by the utility room, though, so there is no escaping it much of the time. On, off, on, off, on, off, on, off, all day long. On installation day I asked the plumber about it and he said, "It's probably the fan, but no one has ever complained about the noise before." It was the end of a long day and so I didn't pursue it. But fast forward two months later and the noise is really annoying. I know we could turn off or change the timer settings, but that defeats the purpose of getting instant hot water. My question is: Is this noise normal? I'm reluctant to bring back the plumbers if it's something we'll just have to live with. Thanks in advance for sharing experience and advice.
Comments (10)
mimola
2 years agoRelated Discussions
Spin off RE: water heater and recirculating pump
Comments (17)There are different types of heat tracing. I used constant wattage in my system, and can't comment on other types. Aptly named, it produces heat with no limit, thus the need for control(t-stat)...exactly like your water heater. Memory isn't good, so I can't give prices (my system is over 10 years old)but IIRC, there is a minimum footage purchase (10' maybe)and then per/ft. cost. Insulation cost is a wash- any system should be insulated. My system is designed to maintain a temp. just under the heater setpoint. The longer the insulation maintains static condition the less power used. Cost for my system with expensive, quality pipe insulation was well under a circ. pump. Installation requires no plumbing, but does require minor electrical skills if power isn't nearby. Installing the trace and insulating will take longer than installing a pump (without return line- which could extend time considerably), but is not skilled work, simply conscientious. My situation has 20' of trace,@5W/ft. At the old kWh rate (just increased), operating costs were penny/hour. Note the system does not operate continuously. Circ. pumps consume power starting at ~400W, 4x my consumption, though of course they are intermittent duty too....See MoreNew construction and recirculating hot water pump
Comments (14)napa I have 2 Rinnai tankless hotwater generators in series and I had to install a recirc pump since my generators are directly under the master suite (nice) but 88 feet away from the kitchen (long wait). The way I hooked mine up was to actually bypass the tankless hot water generators becuase I did not want the generators to cycle just to maintain hot water in the recirc loop. Instead, i bought a small 4 gallon electric tank and use the small tank to maintain hotwater in the line. If you go this route, then you can use a very small pump (i used the smt-303 laing pump that consumes 30 watts of power - see http://www.hvacquick.com for info). The recirc loop is connected to the main hotwater supply line just after the output of the hotwater generators - and then at the distant end just before all the branch lines going to various sinks. The supply side of the loop starts as 1 inch and then goes to 3/4 inch CPVC. The return loop i installed is 1/2 inch CPVC. I insulated the entire loop. The return side of the loop dumps into the 4 gallon tank and then on to the pump which pushes the hot water into the supply side of the loop. I also have a few shut off valves, a bleeder pipe& valve to remove air (very important), and an air vent (also very important). Laing now makes a new pump that has an integrated check value in it and that made the plumbing easier. I did not see that listed on the hvacquick site - call them and ask about the new pump. otherwise, you have to install a seperate check value - not a big deal, but the value must be matched to work with the pump (the output pressure of the pump is low). I used the white paper on the hvacquick.com web site (i think Laing also has some info on their web site) but modified it a bit for the tankless connection. This all started out when I wanted to supply my humidifiers with warm water and I realized that the tankless hot water generators would be kicking on and off whenever the hvac turned on - not waht I wanted. At the same time I then discovered the hot water delay issue. So my recirc system was designed to serve two puposes. I tapped off the recirc loop to supply 2 humidifers and it also keeps hot water in the line for the sinks. It works quite well. Whenever we turn on a sink at the distant end, we have a short delay (about 15 seconds) for the hot water in the recirc loop to push though the branch lines. The hot water generators kick in to backfill the hot water we use with a new supply of hot water. Whent he humidifiers kick in - the flow rate is so low that the hot water generators don't kick on (what I wanted) and the line is backfilled with a small amount of cold water. The small hot water tank then heats the water in the loop to the preset temp....See Morecan you recommend a recirculating pump?
Comments (13)The systems that force the cold water back into the cold line are a jury rig solution to eliminate the need for the extra return line. If you are building you can easily put in the return line (and insulate the hot line). There are numerous ways to turn on the circulating pump, from using a light switch (often works well in a bathroom) to timers, motion sensors, etc. If you use low voltage equipment and a relay to switch the pump even the wiring is simplified (think thermostat type wiring with lower voltage and current). If you put eh demand heater in the circulating loop it will be turned on when it detects the flow from the pump and deliver hot water. If things are sized correctly and set up correctly you should have very close tom instant hot water by the time you turn on the sink faucet....See MoreRinnai Water Heater with Recirculation
Comments (5)Hi Naomi Arcadia, The reviews on the app? Am I misunderstanding something? Don't make a water heater purchasing decision based on the reviews of the app. Using your phone to control the water heater or the circ pump sounds like a complete boondoggle. I like tankless water heaters - I've installed one each in my last two houses. If you need a circ pump, put it on a motion detection switch so it goes on when you walk in a bathroom and runs until the water line is warm. A better solution is to design your plumbing so it's not a long run from the water heater. If you have a basement or a garage in a warm climate, consider using an electric hybrid tank heater instead. A tank heater can reduce the need for circulation pumps. The hybrid tank will usually cost slightly less to operate than the best gas tankless....See Moremimola
2 years agoJake, thank you for suggesting that we determine whether the noise is the same whether or not the burner is on. It is not. The noise occurs only when the burner is off and the pump is on. We know this because the controller (see pic below) indicates burner status via a flame icon to the left of the temperature. When the burner is on, the flame icon shows. At the same time, a red light on the tankless unit flashes slowly. According to the manual, this "indicates ignition and pump operation." The annoying noise does not occur during this time. It happens right after the the flame icon disappears and the red light goes into rapid flash, which "indicates pump operation with no ignition." The noise stops when the flame icon reappears and the red light goes back to slow flashes. Your post seemed to suggest that the fan (which our plumber suggested was the source of the noise) is connected to the burner operation, not the pump. From the info I've given you now, do you have further advice or comments? Or does anyone else? Thank you very much.
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