Water pump surging — sometimes

[LuckyDuck]

I decided to sanitize my water system today, filling up the FW tank with the appropriate bleach/water dilution. I set the hot and cold valves to bypass the hot water tank, which is empty, as I didn’t want the bleach water in there. I turned the water pump on and then opened each faucet until I smelled bleach. For some reason, when I turn on the bathroom hot faucet, the pump “surges,” rather than running consistently, although the flow is normal. Kind of an UMM-hmm-UMM-hmm sound. It runs normally on all the other faucets, hot or cold. And if I open the cold tap in the bathroom along with the hot, the surging stops — pump hums as usual. Oh, and if I reduce the flow of the hot faucet, the surging becomes “faster.”

I did check and clean the strainer on the pump before I started. It’s back on nice and tight. No leaks anywhere that I can see. Funny thing is it didn’t do this when I first turned on the bathroom hot faucet. Only after going back to do it a second or third time. It’s your basic Shurflo pump. I have only used the pump for sanitizing as we have always camped with city connect, so it’s not life or death. But it still bugs me. I’m stumped — any advice? TIA!

[Cavie]

I'm guessing your bypass valves are not compleatly where they should be. Drain the bleach water, fill the WH. She WH valves and try the pump.

[Nature Ist]

I assume your pump is the modulating type that cycles itself off when the pressure reaches a certain point and will go back on when the pressure drops, but between those cycles, it has a back-flow valve that releases some of the pressure so the pump doesn't cycle too rapidly. It would seem you have some form of restriction in your bathroom hot faucet valve or the line leading to it. However, I would first continue to bleed all the chlorinated water out of the system and switch the hot water tank over to normal operation. When is it filled with water and in normal operation, try the bathroom hot faucet again. If the issue remains, I would drain the water system again, which may drain any contaminants the may have lodged in the valve. Be sure to open only that hot water valve to drain the line. Turn the water back on, and try again to see if you still experience the same problem. My next recommendation would be to disassemble the hot valve to check the valve seat and washer, it could be as simple as a bad washer. If you notice any less flow at full open position on the bathroom faucet compared to the cold valve, that further suggests restriction in the hot valve body.
If you had the same issue everywhere, I would suggest adjusting the pump's back-flow setting, but that isn't advisable if only one valve is causing this issue.
You can simulate this condition by turning on any other faucet and then closing it slowly, you should experience the same "pulsing" of the pump.

[LuckyDuck]

Thank you! Great info to get me started. It’s weird that the problem seems isolated to the BR hot faucet.

[stateboy]

I would also make sure you remove the screen on the spigot of the bathroom sink in case anything (scale, etc.) breaks free in the hot water line that the screen might catch. It's not likely anything is in there now since running cold water out of the same spigot doesn't produce that same pulsing of the pump the hot water side does but it doesn't hurt to clear it.

[LuckyDuck]

Thanks! Actually that was the first thing I tried, but couldn’t get it off. Have to get some rubber-coated gloves to get a grip on it.

[RetiredOne]

Originally Posted by LuckyDuck

Thank you! Great info to get me started. It’s weird that the problem seems isolated to the BR hot faucet.

Did you bleed out the shower on hot/cold? It could be an air pocket since you're closer to the shower. Also, flush the toilet too, low point drains and outside shower if you have one to purge all air.

[LuckyDuck]

Yes, I did run both H/C tub snd shower valves and the H/C in the outside shower. But I didn’t flush the toilet. Will try that and the low-point drains. Thanks!

[LuckyDuck]

So, I tried mightily to unscrew the aerator on the bathroom faucet, but it won’t budge! Don’t want to break something as I assume it’s just plastic. Is there a trick? Or does the aerator just not come off? Picture shows the faucet I have.

[JFlightRisk]

No trick to it, anymore than a faucet in your house. If it doesn't want to budge, it may not be removable. The original equipment faucet in our bathroom didn't have a removable aerator, so I replaced it with a residential one. If you're feeling adventurous, take it off the sink and pull off the bottom spout cover, and it'll be self explanatory when you look at it.

[LuckyDuck]

Yes, I have a feeling it’s not removable. I actually don’t mind the sink — looks better than a lot of those I’ve seen, but it’s crazy to have a “permanent” aerator screen. Thanks for the suggestions!

[Nature Ist]

Originally Posted by LuckyDuck

So, I tried mightily to unscrew the aerator on the bathroom faucet, but it won’t budge! Don’t want to break something as I assume it’s just plastic. Is there a trick? Or does the aerator just not come off? Picture shows the faucet I have.

I have what appears to be the same faucet. Though there is no flat spot to put a wrench on, my aerator does unscrew. It was tight, but I got mine off using my fingers. I would suggest using something like the old jar opener grip pads that used to be popular, any rubber-like flexible material should work.
Though I don't think the strainer is your problem, the suggestion you remove it is certainly correct. It's probably something we should all do annually at the least.
Your next trick will be removing the valve body if you cannot clear the line by draining it.
As suggested, you could remove the entire faucet, then try to flush it with air or water pressure where you can see what you are doing and possibly observe anything that gets flushed out.

[LuckyDuck]

Funny, that’s exactly what I used — a jar opener grip pad. Although my hands will never be mistaken for vice grips, I’ve broken my share of things by forcing them when I shouldn’t, so I was reluctant to get too crazy. I’ll try again. I’m wondering if jury-rigging something with my compressor to blow air back through the faucet strainer and through the hot line might work and avoid disassembling the faucet? Maybe using my Water Bandit? Just spit-balling here. Thanks for the help!

[RetiredOne]

Did you try wrapping a rag around the aerator and try giving a small twist with a pair of channel lock type pliers? This has worked for me in the past to free up a tight aerator.

[Screwby]

I guess worst case you do break it and then replace it with a quality residential one lol. I agree with the above statement about restriction. I can replicate the same surging pump by barely cracking open my faucet so the pump can just build pressure then loses it because the faucet isn’t completely shut off.

[Nature Ist]

Originally Posted by LuckyDuck

Funny, that’s exactly what I used — a jar opener grip pad. Although my hands will never be mistaken for vice grips, I’ve broken my share of things by forcing them when I shouldn’t, so I was reluctant to get too crazy. I’ll try again. I’m wondering if jury-rigging something with my compressor to blow air back through the faucet strainer and through the hot line might work and avoid disassembling the faucet? Maybe using my Water Bandit? Just spit-balling here. Thanks for the help!

Yes, the water bandit or any equivalent would work. It would probably work best to do the back-flush with water, so that might be the perfect way to accomplish that. I would also set the water heater to by-pass so you don't blow whatever it is into the water heater tank, only to get it back later on.
Which brings up another suggestion: if you haven't already, you should flush the water heater to clear out any sludge or deposits that could become a problem later.

[LuckyDuck]

Thanks. I may give that a go. Yes, I flushed and drained the water heater last fall before covering her up for the winter.

[LuckyDuck]

Closing the loop on this... It looks like I fixed the surging. I “back flushed” the hot line by attaching a FW hose to the faucet spout with my Water Bandit. No more surging when I ran it with the pump. But of course, one fix leads to new discoveries — both hot and cold pex lines were leaking slightly at the connection with the faucets. So, I unscrewed both and tried to put Teflon tape on the threads and re-attach. Trying to tape fittings blind up under a sink is near impossible. Seemed to solve the cold, but not sure about hot. Replacing with shark bites doesn’t seem any easier. After all that, I discovered the weight of DW’s bath supplies broke loose the flimsy shelf under the counter. So, I finished the day by crafting a T-brace support. Another job for a contortionist, which I’m not. Aren’t RVs fun?

[JFlightRisk]

Originally Posted by LuckyDuck

Aren’t RVs fun?

They do tend to bring out the creativity in us. And sometimes the questions...like yours!

[LuckyDuck]

Originally Posted by JFlightRisk

They do tend to bring out the creativity in us. And sometimes the questions...like yours!

I love challenges. And projects. So all is good!