Quest to tame pump noise - solved

[daleyocum]

I seem to be uncommonly sensitive to the sound of the water pump, especially at medium flows when it comes on and off brrr...brrr...brrr. For some reason it drives me crazy.

I started out installing the Shurflo pump silencing kit which helped isolate the pump vibration from the fixed pipes in the trailer but it didn't solve it by any means.

Next I installed the Shurflo accumulator which provides some extra damping to the system. It's basically a tank with a diaphragm inside, water on one side, air on the other. The calms down some of the brrr...brrr but it's still there.

I stumbled across a new electronic device on this post and gave it a try. It has the catchy name IRVWPC for Intelligent RV Water Pump Controller. It's a microprocessor that uses a sensor to measure the pressure in the system and then varies the speed of the existing water pump (mine's the stock Shurflo 4008) to maintain a constant pressure. For you techies it uses a PID loop. One model has settings for both conventional hot water tanks and tankless systems. That matters because conventional Atwood hot water heaters have a air bubble at the top by design and that extra cushioning in the system needs to be accounted for in the device tuning. If you are REALLY technical, the device even lets you mess with the PID constants. I haven't bothered, though.

Anyway, the end result is you turn on the faucet and water comes out and the pump purrs at the speed it needs to in order produce that water. The pump no longer pulsates. At all. It's far quieter than before, to the point that I'm finally satisfied and that's saying something.

It only takes 30 minutes or less to install. Anyone generally handy should be able to do it or you could have any dealer or mobile RV tech do the job.

I've also been extremely impressed with the support provided. This is a quality device backed up by folks who care. Check it out at https://www.irvwpc.com/. I have no affiliation with this company, I'm just a satisfied customer.

P.S. If you have a conventional hot water heater, be sure to ask them for the model that supports that.

[OTRA15]

Thanks for all the details . . . very helpful.

[ROBERT CROSS]

Very Kool... Our pump only makes noise when on and the running water almost drowns it out...I did mount it on rubber feet to stifle the vibration.
POI it is a new SurFlo...which is considerably less noisy than the OEM unit.
You should have heard the air pump on the "Frantic Banana's" air pressure system...BangBang & shake.

Bob
🇺🇸

[jftompkins]

My quest as well. Has anyone converted the original OEM Shurflo fixed speed on/off pump to their or other manufacturers) “smart” pump (variable speed with integrated pressure sensor) for operating through the demand curve. A PD pump generally is simple in flow characteristics for proportional control. I believe these pumps are more common in the marine industry.... but can see the value of the post and reasonable price under $200. One other note, my pump is wired on the same circuit as the bathroom LED lights .... not forgiving with respect to voltage fluctuations - blink. Shurflo I believe in their manual recommends a separate circuit for the pump for this very reason....AS engineering? This might be difficult to run a separate line from the bathroom switch to the distribution board. I’m curious if anyone has put in a capacitor in the circuit to dampen surges to keep LED lights from flickering with pump running.... much like an audio capacitor to drive a subwoofer in car that was not designed for retrofit stereo power outputs....? Not really a big deal just a bit annoying.

[daleyocum]

Originally Posted by jftompkins

My quest as well. Has anyone converted the original OEM Shurflo fixed speed on/off pump to their or other manufacturers) “smart” pump (variable speed with integrated pressure sensor) for operating through the demand curve. A PD pump generally is simple in flow characteristics for proportional control. I believe these pumps are more common in the marine industry.... but can see the value of the post and reasonable price under $200. One other note, my pump is wired on the same circuit as the bathroom LED lights .... not forgiving with respect to voltage fluctuations - blink. Shurflo I believe in their manual recommends a separate circuit for the pump for this very reason....AS engineering? This might be difficult to run a separate line from the bathroom switch to the distribution board. I’m curious if anyone has put in a capacitor in the circuit to dampen surges to keep LED lights from flickering with pump running.... much like an audio capacitor to drive a subwoofer in car that was not designed for retrofit stereo power outputs....? Not really a big deal just a bit annoying.

My GUESS is the IRVWPC unit discussed here would make the flickering less because the pump isn't going from full on to off over and over. Your idea of a capacitor is a good one as well. You could install one next to the pump just because it's easier. The bigger the better.

[jftompkins]

Originally Posted by daleyocum

My GUESS is the IRVWPC unit discussed here would make the flickering less because the pump isn't going from full on to off over and over. Your idea of a capacitor is a good one as well. You could install one next to the pump just because it's easier. The bigger the better.

Thanks - will take a closer look at that capacitor. My concern is a third-party device that controls both the pump and the hot water heater for safety/warranty on essentially what is a pressurized hot water boiler. Maybe more concerning are the new on-demand water heaters.... with more flow and pressure sensors that are getting pulsed by the very nature of a PD pump moving an incompressible fluid water; and the more complex logic controls than the tank systems. Had actually seen an independent post about bypassing a safety switch to improve demand response rate....? In the Girard manual it actually says “ confirm that there is a steady water flow (not pulsating)”....what a PD pump does.
The more I read ....am thinking simple is better....am going to give it a year; not a priority.

[GetawA-S]

One wonders if this could be used to control a spare pump on a loop from the water heater outlet back to the inlet, through a solar heat collector to heat the contents without propane. The controller input would be a temperature sensor on the collector outlet.
Of course, most hot water usage is after sundown, so it would be a one and done setup.

[LNBright]

So, new AS owner, it was winterized before we brought it home in January; I readied it for our first use, and was a bit surprised how noisy it was, but thought maybe I’d get used to it... on our first trip in late March, the DW didn’t seem to mind, but I cringed every time water was used, thinking we were waking up the campground. Came home, and started reading about accumulators, and other possibilities. Then I saw Dale’s mention of this, started eyeing it. So, I’ve ordered one, once it arrives and is installed, I’ll report back how it works for us.

[daleyocum]

Originally Posted by LNBright

So, new AS owner, it was winterized before we brought it home in January; I readied it for our first use, and was a bit surprised how noisy it was, but thought maybe I’d get used to it... on our first trip in late March, the DW didn’t seem to mind, but I cringed every time water was used, thinking we were waking up the campground. Came home, and started reading about accumulators, and other possibilities. Then I saw Dale’s mention of this, started eyeing it. So, I’ve ordered one, once it arrives and is installed, I’ll report back how it works for us.

While you’re in there messing with the pump, I’d recommend adding the Shurflo pump silencing kit in addition. It’s cheap and addresses half of the problem.

[RivetED]

This is on the to-do list but I haven't reached number 32 yet! I like jftompkins' idea of adding a cap at the pump. You can get 1 Fared (that's big) caps now-a-days for under $50.-. But as mentioned I suspect a variable speed pump won't have the heavy on/off demands for current as the stock pumps do.

I had one of the early sensor/variable speed type pumps in my '04 and when it worked it was great. Its biggest issue was it would sometimes have to be reset (remove voltage) to get it to 'sense' the drop in pressure. I know of 2 other A/S'ers that installed them but gave up because of the reset problems. They also draw a lot of current and weren't boondocker friendly. This was an approx. '08 product, I'm sure the recent designs are more stable.

[LNBright]

Ok, to report back:

I'd ordered the IRVWPC device, and watched the install video over and over. Was ready to tackle this. Pulled the kickplate and the drawers out for access, and... found I didn't even have a Shurflo in there, as the PO had replaced the pump w/ a FloJet (which, is supposedly quieter than the Shurflo), w/ appropriate silencing hosing. But, the IRVWPC isn't pump-specific: I spent a lot more time going back and forth between looking at what my current setup was and the install video again, and again. Finally ciphered through what I would need to do differently, tackled it, and it was still a pretty easy install. The 'hitch' was, I was tackling this the day before we were to get back down to freezing (I'm in the south, winter was supposed to be gone!), so I held off on filling up the tank and really putting it through its paces. But, w/ the last of the cold snap having passed, I tried it out. And, it helped.

Maybe I had 'too high of a hope' that it would make the pump non-detectable. You definitely still know the pump has kicked on. But, it's not as loud or as 'violent' sounding as it was. And, I suppose this is the bigger point: if I have someone inside the AS turning a faucet on and off while I'm on the outside listening, it isn't obnoxiously loud. When we were camping, I thought we were waking up the whole campground: now, I can comfortably use the water without thinking we're being obnoxious neighbors.

[LNBright]

One nifty thing I did think to do: I mounted the controller box to the furnace mount, under the microwave/convection oven, behind the ’kickplate’ that hides the furnace. That way, I can snap it off and see the pump controller’s lights to know if there’s an error or some such going on with it.