Shower hot/cold problem

[Houndwalker]

I winterized in early November and took out rig out for the first time this weekend.

I've never have had this happen before but when showering using the water pump, the temp would cycle from hot/comfortable to cold and back again. In sync with the water pump. When the pump runs the water is hot - when the pump cycles off the water gets cold. This repeats during the entire shower - not pleasant. Again, this is the first time we've experienced this and we've owned our SS since 2019 and put ~45k miles on it with lots of showering when boondocking.

This doesn't happen when connected to city water and this cycling from hot to cold doesn't happen at the kitchen or bathroom sinks.

We replaced the stock shower head with this Oxygenics model in 2021.

Any ideas what is causing this?

[BehindBars]

Since winterizing was brought up, I’d suggest a verification of the water heater bypass valve settings.

[kenandterry]

Originally Posted by Houndwalker

I winterized in early November and took out rig out for the first time this weekend.

I've never have had this happen before but when showering using the water pump, the temp would cycle from hot/comfortable to cold and back again. In sync with the water pump. When the pump runs the water is hot - when the pump cycles off the water gets cold. This repeats during the entire shower - not pleasant. Again, this is the first time we've experienced this and we've owned our SS since 2019 and put ~45k miles on it with lots of showering when boondocking.

This doesn't happen when connected to city water and this cycling from hot to cold doesn't happen at the kitchen or bathroom sinks.

We replaced the stock shower head with this Oxygenics model in 2021.

Any ideas what is causing this?

1. When we use the OEM onboard water pump, it runs constantly…..not on and off as you describe. Is this the way your pump has ALWAYS worked?

2. Do you have any kind of blending valve on the shower line? Any water conservation modification to the shower head?

3. Are you sure the outside shower valves are completely closed? (If equipped)

[BehindBars]

kenandterry’s comment reminded me that my Sunseeker’s water pump recently began cycling on and off even during wide open faucet situations, and the water pressure was abnormally low. It turned out the water pump pressure switch went out of adjustment and caused unnecessary cycling. This does not explain your water temperature variations but may also be something to look into - pump pressure switch setting.

[Houndwalker]

Originally Posted by BehindBars

Since winterizing was brought up, I’d suggest a verification of the water heater bypass valve settings.

Thanks for your input. I should have mentioned that this was the first thing I confirmed was correct.

[Houndwalker]

Originally Posted by kenandterry

1. When we use the OEM onboard water pump, it runs constantly…..not on and off as you describe. Is this the way your pump has ALWAYS worked?

2. Do you have any kind of blending valve on the shower line? Any water conservation modification to the shower head?

3. Are you sure the outside shower valves are completely closed? (If equipped)

1 Yes, our OEM pump has always worked this way. I think our other RVs have also worked in a similar fashion.


2 Huh, no idea.


3 That is a very good question I'll check it out.

[Duckogram]

Applying logic here:
The pump only pumps cold water.
The water heater is working as you get hot water when the pump is running.
The water system is pressurizing (pressure unknown) because the pump shuts off.
Sooo, there are 3 ways to get cold water into your hot water line, Shower mixer valve, outdoor shower mixer valve and the water heater bypass valves.
Since your faucets work normally the bypass valve is not likely.

As Cap’n Ken suggested, you may have a shower miser (#2 Huh). A photo of your shower valve will answer that question.

Your oxygenics only squirts what the valves send to it.

[JLeising]

Sounds to me like when the pressure drops, there is insufficient pressure for hot water flow. I would check for some partial blockage in the hot water system. Flushed the hot water tank recently? Shower valve? Junk from the hot water tank flowing to the valve?

[5picker]

Is this a tank type heater or tankless?
Make and model would be helpful.

[BehindBars]

Originally Posted by 5picker

Is this a tank type heater or tankless?
Make and model would be helpful.

2017 Sunseeker 3010DS (per OP signature); 6 gallon tank water heater.

[5picker]

Originally Posted by BehindBars

2017 Sunseeker 3010DS (per OP signature); 6 gallon tank water heater.

Thanks, lets hope so.

2017 could have been changed and signatures don't show in the mobile app.
Putting the pertinent information in the body of the thread asking for help about a particular item is imperative.

And even if it is a tank type, some tanks have bypass valves behind the tank, some have bypass valves in a wet bay and some have check valves (no manual valve at all) in the hot outlet.

Knowing what we are giving advice on and how it may be configured, helps with the guessing.

[NavyLCDR]

Three things, maybe to add:
If the water heater was upgraded to a tankless, then lower flow with the pump shut off could trip the flow sensing valve and be causing it to shut off.

There is probably a check valve on the outlet of the water heater. I think they are spring operated but not sure. Lower flow when the pump shuts off might be causing that check valve to close, stopping hot water flow out of the water heater. That would cause cold water almost instantly at the shower.

My water pump runs continuously with the shower on - I would look at adjusting the pressure switch to stop the cycling with the shower. Or adding an accumulator.

[BehindBars]

Originally Posted by 5picker

Thanks, lets hope so.

2017 could have been changed and signatures don't show in the mobile app.
Putting the pertinent information in the body of the thread asking for help about a particular item is imperative.

And even if it is a tank type, some tanks have bypass valves behind the tank, some have bypass valves in a wet bay and some have check valves (no manual valve at all) in the hot outlet.

Knowing what we are giving advice on and how it may be configured, helps with the guessing.

If the poster shows their RV year/model in their signature, and posts in the appropriate brand subforum, why say it's imperative to post it in the message body?

The shortcomings of the mobile app, which I don’t use, seem to be the source of an awful lot of confusion and misinformation on Forest River Forums. It leads to much guessing and assumptions. For that reason, I always use the full site version, even on my phone or tablet, which allows all available info to be visible to me prior to posting replies. Signatures, subforum titles, and forum member profiles are readily visible or available on the full site pages.

If you find yourself lacking important information on the mobile page, click View Full Site down in the lower left corner.

[5picker]

Originally Posted by BehindBars

If the poster shows their RV year/model in their signature, and posts in the appropriate brand subforum, why say it's imperative to post it in the message body?

The shortcomings of the mobile app, which I don’t use, seem to be the source of an awful lot of confusion and misinformation on Forest River Forums. It leads to much guessing and assumptions. For that reason, I always use the full site version, even on my phone or tablet, which allows all available info to be visible to me prior to posting replies. Signatures, subforum titles, and forum member profiles are readily visible or available on the full site pages.

Because we have no clue what modifications they may have made since taking ownership. (or before)

It really isn't hard when asking a question about a specific appliance to include ALL the information necessary about that item, including make and model.

If someone is coming here for help, I'd rather be able to give them accurate information instead of general guesses that may/may not pertain.

As for the mobile app shortcomings... yes there are some but they would be way less if the information was in the body of the post as I mentioned.

I'm glad you always have access to a computer.
Many of us do not always have that luxury and viewing the forum on a web browser on a small screen phone is not the best. A tablet maybe.
I am on the go a lot but can easily check in on the app. I always have my phone. I don't always have a tablet or a PC on my lap.

I think part of forum etiquette is letting folks know the best practices to better the forum. I don't believe it unfair to ask folks to include the information necessary to make informed replies when they haven't provided that.

[BehindBars]

Originally Posted by 5picker

I'm glad you always have access to a computer.
Many of us do not always have that luxury and viewing the forum on a web browser on a small screen phone is not the best. A tablet maybe.
I am on the go a lot but can easily check in on the app. I always have my phone. I don't always have a tablet or a PC on my lap.

You made an incorrect assumption. I do not always have access to a desktop computer. I use the full site version even on a 4 inch iPhone because I don't want to post bad or irrelevant advice based on the limited information provided by the forum's mobile version. If people want to use the mobile version, that's fine, but if they want to ensure that they post relevant advice, they could realize they may need to take it upon themselves to look for the signature and subforum titles, if those are lacking on the mobile version.

[5picker]

Originally Posted by BehindBars

You made an incorrect assumption. I do not always have access to a desktop computer. I use the full site version even on a 4 inch iPhone because I don't want to post bad or irrelevant advice based on the limited information provided by the forum's mobile version. If people want to use the mobile version, that's fine, but if they want to ensure that they post relevant advice, they could realize they may need to take it upon themselves to look for the signature and subforum titles, if those are lacking on the mobile version.

You win... I'm out before I give out incorrect advice.

[Houndwalker]

Thanks everyone for the helpful input! Update on my situation:

1. Water heater is the 6 gallon factory unit
2. Bypass value behind water heater is closed
3. Outside shower values are closed
4. No water conservation mod since the Oxygenics shower head was installed in 2021 (shower has worked fine until now)
5. Disconnected the shower head and it appears clean, no debris blocking the flow

Ideas to pursue today:

1. Shower blending values (not sure how to check these?)
2. Outside shower, does it exhibit the same problem
3. Water pump pressure switch setting
4. Water tank check value
5. Does water pump run continuously with shower head disconnected
6. Flush hot water tank (never done so probably a good idea)

[maxxtc]

Put an inline accumulator tank. Your problem will be solved

[NavyLCDR]

Originally Posted by maxxtc

Put an inline accumulator tank. Your problem will be solved

Except that there should be no problem without the accumulator tank.

[mercury9]

what about a partial blockage? maybe when the pump runs you're getting a little more pressure to the hot side