Water oddity

frank r · 05-04-2022, 04:27 AM

- 2019 Passport GT 2920BH
- Dometic/Atwood GC6AA10E water heater
- Shurflo 4008 water pump (2.5 years old)

Took it out for the first trip of the season this past weekend, and have an odd combination of water symptoms going on. Occasionally after running the hot water, the pump remains on - but at a much lower speed (judged solely by noise level). This seems strange to me, since the 4008 is a single-speed pump. The only way to get the pump to shut off is to run the hot water again, wait for the pump to kick on full speed then shut the water off. When I do this, the hot water has a very low flow initially, sputters as if there was air in the lines then comes on full-flow. As the pump is re-filling the water heater, there is a "gurgling" noise coming from the tank that was not present beforehand. To further complicate diagnosis, I am also experiencing intermittent short bursts of hot water coming from cold faucets (all faucets are dual-handle types).

Initial thoughts are it's either the pump beginning to fail or the check valve in the outlet of the hot water tank - however I don't understand how either of these would cause all of these symptoms. Any input and/or troubleshooting advice will be greatly appreciated.

Thank you.

Javi · 05-04-2022, 04:51 AM

Quote:

Originally Posted by frank r

- 2019 Passport GT 2920BH
- Dometic/Atwood GC6AA10E water heater
- Shurflo 4008 water pump (2.5 years old)

Took it out for the first trip of the season this past weekend, and have an odd combination of water symptoms going on. Occasionally after running the hot water, the pump remains on - but at a much lower speed (judged solely by noise level). This seems strange to me, since the 4008 is a single-speed pump. The only way to get the pump to shut off is to run the hot water again, wait for the pump to kick on full speed then shut the water off. When I do this, the hot water has a very low flow initially, sputters as if there was air in the lines then comes on full-flow. As the pump is re-filling the water heater, there is a "gurgling" noise coming from the tank that was not present beforehand. To further complicate diagnosis, I am also experiencing intermittent short bursts of hot water coming from cold faucets (all faucets are dual-handle types).

Initial thoughts are it's either the pump beginning to fail or the check valve in the outlet of the hot water tank - however I don't understand how either of these would cause all of these symptoms. Any input and/or troubleshooting advice will be greatly appreciated.

Thank you.

first... go check to see if the outdoor shower valves are on/open ..

Then look at your winterizing valves and fresh tank fill valve if you have one..

**flybouy** · 05-04-2022, 05:06 AM

How hot is your hot water? If the thermostate has failed it can turn the WH into a large pressure cooker until you either relive the pressure by opening a faucet or the pressure/temp safety valve opens. Check it with power off and cooled down by lifting the lever and see if it opens easily.

frank r · 05-04-2022, 05:36 AM

Thank you for the input.

- Outside shower is turned off (verified).
- TT Does not have a tank fill valve.
- Winterizing bypass valve on WH is in correct position (turned facing the WH inlet).
- Hot water is normal temp, WH does not seem to be running more than/longer than normal.
- WH pressure relief valve opens manually as normal.

Balvar24 · 05-04-2022, 08:27 AM

Hot water from the cold faucets just about has to be at a fixture. Culprits are the outdoor shower mentioned above as well as the indoor shower. If you leave the hot and cold on with the handheld valve closed, you can get cross flow between the hot and cold.

frank r · 05-04-2022, 08:32 AM

Quote:

Originally Posted by Balvar24

Hot water from the cold faucets just about has to be at a fixture. Culprits are the outdoor shower mentioned above as well as the indoor shower. If you leave the hot and cold on with the handheld valve closed, you can get cross flow between the hot and cold.

The showers were checked and both had been properly shut off.

Balvar24 · 05-04-2022, 09:30 AM

Water heater plumbed backwards?

frank r · 05-04-2022, 09:31 AM

Quote:

Originally Posted by Balvar24

Water heater plumbed backwards?

Not unless someone broke in over the winter and re-plumbed it.

dutchmensport · 05-04-2022, 09:46 AM

When the trailer was winterized last, was it winterized with RV antifreeze or was the blow-out method used?

I have 2 theories if the blow-out method was used. First is, some water droplets were left in the faucets and they froze, causing a crack or a leak, allowing hot and cold to be working incorrect. Second, you could have a crack or break at the water pump itself, allowing air to be sucked into the system, thus keeping the pump running and running. (and 3rd, it could be both.)

Now, if the camper was winterized with RV antifreeze, then nothing should have frozen. Something else is going on... like the check valve at the water heater. I still think the water pump is sucking air from somewhere though. (it could be both too).

Javi · 05-04-2022, 09:47 AM

One way valve on back of water heater.

frank r · 05-04-2022, 10:00 AM

Quote:

Originally Posted by dutchmensport

When the trailer was winterized last, was it winterized with RV antifreeze or was the blow-out method used?

I have 2 theories if the blow-out method was used. First is, some water droplets were left in the faucets and they froze, causing a crack or a leak, allowing hot and cold to be working incorrect. Second, you could have a crack or break at the water pump itself, allowing air to be sucked into the system, thus keeping the pump running and running. (and 3rd, it could be both.)

Now, if the camper was winterized with RV antifreeze, then nothing should have frozen. Something else is going on... like the check valve at the water heater. I still think the water pump is sucking air from somewhere though. (it could be both too).

Anti-freeze method, same as I've done for the past 25 years of TT ownership.

frank r · 05-04-2022, 10:01 AM

Quote:

Originally Posted by Javi

One way valve on back of water heater.

My first thought as well, and I have a new one at home that will go in tonight. We shall see, I guess...

frank r · 05-04-2022, 10:04 AM

Quote:

Originally Posted by frank r

My first thought as well, and I have a new one at home that will go in tonight. We shall see, I guess...

Speaking of, I have a related question: When I removed the Pex threaded connector from the old check valve, a rubber "washer" fell out. The washer is different on both sides, but it fell out so I do not know in which direction it needs to be reinstalled. Any help there?

Balvar24 · 05-04-2022, 10:28 AM

Quote:

Originally Posted by frank r

Not unless someone broke in over the winter and re-plumbed it.

Time to interrogate the wife.

**chuckster57** · 05-04-2022, 11:49 AM

Quote:

Originally Posted by frank r

Speaking of, I have a related question: When I removed the Pex threaded connector from the old check valve, a rubber "washer" fell out. The washer is different on both sides, but it fell out so I do now know in which direction it needs to be reinstalled. Any help there?

It’s probably what’s called a swivel seal, I call them volcano seals. Cheap and I would replace it. Since it’s flat on one edge and “sloped” the flat edge goes into the nut

frank r · 05-04-2022, 04:20 PM

Quote:

Originally Posted by Balvar24

Time to interrogate the wife.

Nah, no need to question the wife, I'm gonna blame her regardless.

frank r · 05-05-2022, 03:55 AM

Update: I replaced the check valve on the outlet of the WH, let it heat up and ran a tank through, using all of the faucets. So far, the pump has cycled normally - shutting off when it should and with no lower running speed. There does still seem to be a tiny bit of air in the cold lines, as it sputters ever so slightly and I am still feeling some intermittent warm (not hot) water mixing in. So long as the pump is shutting off when it should be, I'm happy. We're leaving tomorrow for a long weekend (in the rain of course), so I'll see how it performs then.

Thank you for all of your thoughts and ideas.

**JRTJH** · 05-05-2022, 04:40 AM

If the symptoms are "only when using the onboard water pump" and it's "slowing until it finally shuts off with no water faucets open" then I'd suspect a leak in the supply line from the fresh water tank to the pump inlet....

The variations in water temperature are probably similar to the pressure changes when someone is in the shower and another person flushes the toilet... It produces an "instant temperature change in the shower"... The difference here, is likely the more subtle pressure changes from a "very slightly changing water volume being pumped that's caused by the air being sucked into the pump inlet.....

I'd first check the O-rings on the inlet fitting and to make sure all the clamps are tight.... My guess is the inlet fitting (assuming you have a FloJet pump) is not properly seated.....

frank r · 05-05-2022, 04:44 AM

Quote:

Originally Posted by JRTJH

If the symptoms are "only when using the onboard water pump" and it's "slowing until it finally shuts off with no water faucets open" then I'd suspect a leak in the supply line from the fresh water tank to the pump inlet....

The variations in water temperature are probably similar to the pressure changes when someone is in the shower and another person flushes the toilet... It produces an "instant temperature change in the shower"... The difference here, is likely the more subtle pressure changes from a "very slightly changing water volume being pumped that's caused by the air being sucked into the pump inlet.....

I'd first check the O-rings on the inlet fitting and to make sure all the clamps are tight.... My guess is the inlet fitting (assuming you have a FloJet pump) is not properly seated.....

Thank you for the input. I will make sure the pump inlet hose clamp is tight - I did just re-install that hose after winterizing at the end of last season.

**flybouy** · 05-05-2022, 05:14 AM

Quote:

Originally Posted by frank r

Thank you for the input. I will make sure the pump inlet hose clamp is tight - I did just re-install that hose after winterizing at the end of last season.

This is information that would have helped if known from the beginning. I should have asked in my first reply "what's changed if anything from the last time it worked properly". I've found from working on things and helping others that whatever happened just prior to an issue arising is often the issue. It's also important that when you replace a component that you fully test it for proper operation before making adjustments elsewhere.

I'm not criticizing but just trying to convey good practices. Anyone can make a mistake and installing a new part or component doesn't guarantee that it's ok. That's why it's a good practice to check your work and the integrity of the part before proceeding further. When I was young I helped freinds that would "turn every screw" on a carborator because the engine wouldn't idle smoothly. Often it would be an ignition issue but now diagnosis becomes compounded because the carborator is all misadjusted. I would look at that pump inlet fitting. It's quite possible you had 2 issues going on at simultaneously.

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