Fresh water pump clicking, extremely frequent micro-cycle

[SJI Sailor]

I recently fixed a hot water tank leak on our 2019 C30 (will follow up on that thread separately). Now the water is back on, but the fresh water pump is clicking -- a very, very short burst -- every 5 seconds or so. Annoying!

I would suspect a leak ... except I can't find a leak, and it seems like too short of a pulse. It is something like 1/10th of a second and there is not enough activity to recharge the pressure really at all, just a momentary "pp!" that makes the intake hose jump and does not run at all. When there have been leaks in the past, it was more like, "prrrrrrp" for 1/2 to 1 second that was obviously charging the pressure.

Apart from this, the pump is mostly OK but it does seem to pulsate quite a bit more than previously, during low-flow usage.

Any ideas on where to start? The ones that come to mind to me are:

1. Could it be air in the lines? I drained the water before working on the hot water tank. OTOH, it has been this way now for 1 week, and we've pumped 1/3 a tank of water using all fixtures. And it never did this when winterizing, etc.

2. Could it be a leak that just has such a tiny pulse to recharge?

3. Could it be a defective pump, pressure sensor in the pump, or bits from the tank being emptied caught in the pump? I have a spare pump and could replace it if that seems likely.

Thanks in advance!

 

[Hamster]

I had a similar issue lately and believe it is air in the lines at the hot water tank. Turn on your hot water at the faucet and then go to your hot water tank and open the drain valve. That should purge the air. It worked for me and stopped the pump thinking it needed water.

 

[SJI Sailor]

Thanks and interesting. I just tried that for a few cycles, and it might have helped a little; not a lot.

One thing that makes me wonder is about the hot water valve (and outlet) on our tank being at the bottom. So I'm not sure where the air would go! Is there another valve I am overlooking, somewhere up higher? (I can't see the top of the tank under the refrigerator.)

 

[Hamster]

I opened the valve (black release valve) at the bottom of the hot water tank. You might need to make sure each of your faucets are running the hot water to get the air out of the system.

 

[DBBRanger]

I’ve had this problem in years past. I don’t believe the problem has to do with leaks at all. The cycling is much to fast as you said to have the pressure effected. I found that it was the pressure switch that is on the pump. I think it is a defective switch that erroneously makes contact and then ‘fixes’ itself. My 2 cents!

 

[SJI Sailor]

Thank you, DBB! I am also starting to suspect that. I have a second pump and will switch to that when I get a chance and see what happens.

 

[Hydraulicjump]

Just something else to consider. On my boat (hull #1) they clearly ran into a cycling problem once they built it. There are a lot of elbows in my pex water pipe system and it may well be creating pressure cycling (due to high friction loss when faucets are open) that causes the pump to cycle too frequently. They put in a Johnson pressure accumulator (about the size of a nerf football) right next to the water pump that gets rid of that short cycling. The problem for me is that I have had two of these accumulators fail in the last 4 years. The bladder breaks. And when it does, this short, loud cycling re-occurs, which is how I know it has broken. I have talked to the Johnson pump folks about what is causing the failure of the accumulator and they are stumped, telling me I am unique. Swell. Unique and unlucky, I think.

So if you get to the point where flushing ALL the air out of the system (even with an accumulator, when there is air in the lines I get this same cycling) and replacing your pump does not work, it is easy to splice in an accumulator tank next to the pump.

Just a random thought.

 

[SJI Sailor]

Good thought! One reason that I am thinking to replace the pump is to put in an accumulator at the same time, because I would need to move the pump anyway and swapping is very little additional effort. Maybe one of those -- pump or accumulator -- will solve it ... just have to find the time.

That is interesting about the accumulator failures. I had wondered about their lifespan. It would be a good reason to make that easily accessible.

 

[SJI Sailor]

Update: problem is solved at least for now. What solved it was a new pump and/or accumulator. I did both at once and am not sure which one helped.

I replaced the pump with the Johnson Pumps 5.0 variable speed pump (as discussed in http://www.tugnuts.com/viewtopic.php?f=2&t=16365&p=107089). At the same time, I added an Amarine 0.75 liter accumulator (https://www.amazon.com/Amarine-Made-Pre-Pressurized-Accumulator-Caravan/dp/B07QJYPHM3). I pressurized that to 35 PSI so it would be above the cut-in but below the cut-off levels for the pump (which are 25 and 50, respectively -- those figures are from memory, so perhaps not exact). The Amarine seems a bit cheap and I don't feel especially confident about long-range durability, but it's working well for now. The pump seems excellent and came with a slightly nicer and larger intake strainer than the one from the factory.

Overall the installation was pretty simple. The most difficult thing was figuring out the orientation of everything so both the intake strainer and the accumulator pressure valve would be accessible. That meant that the pump moved a few inches toward the corner and the accumulator went in at 90 degrees next to it. That is on a C30; would vary for RTs, I'm sure.

In the end, I'm not sure whether the problem was the pump or that it needed an accumulator. But my *guess* is that the pump pressure sensor was bad, or perhaps something got into the pump diaphragms. Sometime I will disassemble it and take a look. Either way, the clicking problem is resolved. And, between the variable speed pump and the accumulator, the overall water flow is quieter and better regulated!

 

[Matty]

Based on my research it may have been the addition of a variable speed pump as opposed to a non-variable. The pump senses a difference between pressure between the inlet and outlet sides. When there is lower pressure on the outlet side the pump turns on. The variable speed pump is better able to compensate for the variation on pressure. I understand the accumulator is also supposed to alleviate that situation. Also check for plastic shavings in the pump filter and faucets. I will be changing my pump out soon.

 

[Kaptajnen]

We replaced our pump with a Johnson pump and now have access to clean the stainless steel filter under the floor.
The filter is new and clean, but every time we get back to the boat after a few days, we notice a distinct smell of rotten eggs the first time we turn on the tap.
The smell only lasts for a few minutes, but I assume it emanates from somewhere between the water tank and the pump.
Any suggestions on how to troubleshoot this will be most helpful

 

[Hydraulicjump]

Sorry to say, but that one is in your tank. H2S gas. And your nose can detect it in the parts per billion.

It is time to flush your water tank. There are many options in previous posts on this site. But I have gone with Bruce Moore's (our very able and trusted site monitor) ingenious recipe. One quart of the cheapest vodka you can find. Dump it into a full water tank and let it sit. Then flush the tank. He is right. It gets rid of the smell because, of course, it kills the sulfur-reducing bacteria that are making the hydrogen sulfide gas in your tank.

The downside of the Bruce Moore treatment is that your water will taste a bit "raiseny" (Trader Joe's) or potato-ish ((Seagrams) for a few tank fills. But you can live with that. Once a year, we let our water tank get into a quart of vodka and not drive home. So much cheaper than all the the other alternatives.

Jeff

 

[MarcoArias]

Update: problem is solved at least for now. What solved it was a new pump and/or accumulator. I did both at once and am not sure which one helped.

I replaced the pump with the Johnson Pumps 5.0 variable speed pump (as discussed in http://www.tugnuts.com/viewtopic.php?f=2&t=16365&p=107089). At the same time, I added an Amarine 0.75 liter accumulator (https://www.amazon.com/Amarine-Made-Pre-Pressurized-Accumulator-Caravan/dp/B07QJYPHM3). I pressurized that to 35 PSI so it would be above the cut-in but below the cut-off levels for the pump (which are 25 and 50, respectively -- those figures are from memory, so perhaps not exact). The Amarine seems a bit cheap and I don't feel especially confident about long-range durability, but it's working well for now. The pump seems excellent and came with a slightly nicer and larger intake strainer than the one from the factory.

Overall the installation was pretty simple. The most difficult thing was figuring out the orientation of everything so both the intake strainer and the accumulator pressure valve would be accessible. That meant that the pump moved a few inches toward the corner and the accumulator went in at 90 degrees next to it. That is on a C30; would vary for RTs, I'm sure.

In the end, I'm not sure whether the problem was the pump or that it needed an accumulator. But my *guess* is that the pump pressure sensor was bad, or perhaps something got into the pump diaphragms. Sometime I will disassemble it and take a look. Either way, the clicking problem is resolved. And, between the variable speed pump and the accumulator, the overall water flow is quieter and better regulated!

Hi!

Just a bit more insight on catching any leaks. The pex fittings on your boat are in the following locations:

-Under the head sink faucet
-Behind the shower mixer (accessible through the guest berth paneling)
-Under the galley faucet
-Under the galley cabinetry (accessible through the bottom cabinet shelving, it is held by screws)
-At the hot water heater and the fresh water pump (accessible through the salon floor hatch)
-Behind the transom shower (accessible through the aft center cockpit hatch)

A dirty fresh water filter can also cause the pump to pulse. Feel free to reach out to my email at any time for any other questions.

Thanks!

 

[Gcarlson]

Try making your own accumulator of a vertical piece of 4” pipe. Put a valve on top and maybe a drain valve at the bottom. The air will dissolve into slowly into the water column, but you’ll know it, just drain and recharge.