water pressure woes

[wanderbird]

Hello,

We bought our first TT this summer and loving the RV life. We are still learning all the systems and have come up with a mystery. Our water pump would lose pressure after 5 seconds and the flow comes to a slow drip. It was working fine after we filled water for a few days. We notice the flow slowed after a few days of use. On city water the pressure remains constant. One strange thing we notice is that when we fill the hot water tank, a lot of air travels into the tank. I purge this air and let the pump run until the air stops coming out.

After filling the hot water tank, the pressure is OK for a few days then get weak again. This leads us to believe it is related to the hot water tank? I replaced the pump but this pressure did not improve. The pressure is also low in the bathroom. No visible leaks anywhere. Is there something we are missing? Thanks in advance for any help.

[Maineiacs]

Your pump has two sides - an intake and an outlet. What you're describing could be caused by debris of some type floating in the tank and periodically getting caught in the hose or the screen at the pump. See if you can remove the hose and screen and flush them clean WHILE the blockage is occurring.


Just my 2 cents.

[wanderbird]

Your pump has two sides - an intake and an outlet. What you're describing could be caused by debris of some type floating in the tank and periodically getting caught in the hose or the screen at the pump. See if you can remove the hose and screen and flush them clean WHILE the blockage is occurring.


Just my 2 cents.

I was thinking of that, too. There is no screen for the intake side that I can access. I will try and drain the hoses from the pump via the low point drains near the sink faucet to see if any debris comes out. Barring that, i would have to check every connections?

[chuckster57]

Take the aerator off the bathroom faucet, I bet it’s full of stuff. When you purge the air, run each hot faucet.

[LHaven]

Our water pump would lose pressure after 5 seconds and the flow comes to a slow drip. It was working fine after we filled water for a few days. We notice the flow slowed after a few days of use. On city water the pressure remains constant. One strange thing we notice is that when we fill the hot water tank, a lot of air travels into the tank. I purge this air and let the pump run until the air stops coming out.

After filling the hot water tank, the pressure is OK for a few days then get weak again. This leads us to believe it is related to the hot water tank? I replaced the pump but this pressure did not improve. The pressure is also low in the bathroom. No visible leaks anywhere. Is there something we are missing? Thanks in advance for any help.

When you say "the water pump loses pressure after five seconds," what does that mean? Does the pump start up every five seconds when nobody is using water? Does the water pressure drop to zero but the pump never starts up?

Also puzzling is the phrase, "when we fill the hot water tank." Typically, you have to fill a hot water tank only after you pull the anode or drain plug to empty it, and then only once after you put the plug back in. How often are you doing this? Why are you filling the heater while you are out camping?

You say "on city water the pressure remains constant." Unless you find your rig sitting in a puddle in the morning, that rules out leaks, the heater safety valve, most of the interior plumbing, and clogged fixtures or aerators.

Unless I hear unexpected answers to the above questions, I'm with the guys who think you have macro sized floating debris in the fresh tank that periodically wanders over and blocks the pipe. Symptom would be the water pump laboring continuously but no water pressure at the fixtures. If this is the case, I can't think of an easy fix to it, but if the TT wasn't used, that would be up to your dealer to worry about under warranty.

[QCMan]

What is the water level in your fresh water tank when this happens?

[wanderbird]

When you say "the water pump loses pressure after five seconds," what does that mean? Does the pump start up every five seconds when nobody is using water? Does the water pressure drop to zero but the pump never starts up?

Also puzzling is the phrase, "when we fill the hot water tank." Typically, you have to fill a hot water tank only after you pull the anode or drain plug to empty it, and then only once after you put the plug back in. How often are you doing this? Why are you filling the heater while you are out camping?

You say "on city water the pressure remains constant." Unless you find your rig sitting in a puddle in the morning, that rules out leaks, the heater safety valve, most of the interior plumbing, and clogged fixtures or aerators.

Unless I hear unexpected answers to the above questions, I'm with the guys who think you have macro sized floating debris in the fresh tank that periodically wanders over and blocks the pipe. Symptom would be the water pump laboring continuously but no water pressure at the fixtures. If this is the case, I can't think of an easy fix to it, but if the TT wasn't used, that would be up to your dealer to worry about under warranty.

I drained the water tank on a whim to see if it was causing air leaks. When I did that, the water pressure was OK for a while. I though that fixed it but when I heated the water, the low pressure reappeared. The other odd thing was hot water flowed through the cold valve sometimes.

As for the pump, I was unclear. The pump runs while we open the tap. It is the water flow that decreases.

[wanderbird]

Tank level varies from full to 1/3

[LHaven]

You would be the best judge of this: are all the symptoms you see consistent with a piece of debris in the fresh tank that occasionally wanders over and blocks the draw pipe?

[JRTJH]

I would first carefully inspect the white hose from the fresh water tank to the pump inlet. A cracked fitting on the pump or a bad O-ring on the fitting can (and does) cause this kind of issue. A cut in the white hose or a loose worm gear clamp can also cause the issue as can an "abrasion or wear" where the hose goes through the floor and towing can cause the hose to wear through.

That said, I have seen an occasional water pump with a "pinhole in the diaphragm" that as the pump operates, that pinhole causes the pump to stop/reduce the water volume delivered to the plumbing.

I think, in the past 30 years, since the diaphragm pumps replaced the piston pumps as the "norm", I've seen 3 or 4.

Essentially, what I think happens is the pinhole allows the pump to "lose suction" and the amount of water "pulled into the pump decreases" so necessarily, the amount of water "pushed out of the pump also decreases"...

I'd start by filling the fresh water tank as full as possible, then turn on the pump and open a faucet that has been involved in the decreased volume/pressure. Let the pump run as long as there is water in the tank and see if there is any "decrease at a specific tank level". If you don't see a decrease, refill the tank and try with a different faucet that has been a problem in the past. (remember that you'll be filling your gray tank as you empty the fresh tank, so plan accordingly).

If there is no "revealing malfunction in the above tests" then I'd suspect the pump diaphragm is a good contender for the answer to "why"....

Your trailer should have a FloJet pump. They are a "good brand" with a 2 year warranty. You can buy a replacement on Amazon for around $45-50, so buying a replacement (if you're out of warranty) is not a "outrageous price".

[LHaven]

If there is no "revealing malfunction in the above tests" then I'd suspect the pump diaphragm is a good contender for the answer to "why"....

Your trailer should have a FloJet pump. They are a "good brand" with a 2 year warranty. You can buy a replacement on Amazon for around $45-50, so buying a replacement (if you're out of warranty) is not a "outrageous price".

The only thing that makes this analysis less probable is that he already replaced the pump.

[JRTJH]

The only thing that makes this analysis less probable is that he already replaced the pump.

I missed that comment... Makes for a slim chance it's the pump. So, I'd focus on the fitting, the O-rings and the white "suction hose"...

[Javi]

I'm wondering if he is using the gage to determine that the tank is 1/3 full... we all know how that would work :D

Haven't seen how big that tank is... but it don't take that long to pump a 30-40 gallon tank dry...

[zalewskim]

The description of the problem is somewhat unclear. It sounds to me that the issue involves only the hot water lines. Does pumping through a cold water faucet operate properly and hot water no so? If so, has the valve to the hot water heater been opened?

[Yamatime]

Do you have an outside shower or spray nozzle? If we leave those themes on the water will sometimes do what you are talking about. Make sure the hot and cold on that is shut off. Even though the spray nozzle is off, if the handles that supply the faucet are turned on, it can cause issues in the camper.

[wanderbird]

Thanks for all the answers. I started to winterize the water system today and open the low point drains. I didn't even know about these drains until I started reading on this forum. I drained into a bucket and found a bunch of crud, water scales, etc. I then closed up the drains and ran the pump again. The pressure is better, not amazing, but it doesn't drop off after 5 secs of running. There must be more crude in there so next time we use the trailer, I am going to run city water with the low points drain open and see if more stuff gets flushed. Oregon gets a few night of freezing and warm up again so I am not using antifreeze yet, just draining and blowing water out with compressed air.

[flybouy]

Thanks for all the answers. I started to winterize the water system today and open the low point drains. I didn't even know about these drains until I started reading on this forum. I drained into a bucket and found a bunch of crud, water scales, etc. I then closed up the drains and ran the pump again. The pressure is better, not amazing, but it doesn't drop off after 5 secs of running. There must be more crude in there so next time we use the trailer, I am going to run city water with the low points drain open and see if more stuff gets flushed. Oregon gets a few night of freezing and warm up again so I am not using antifreeze yet, just draining and blowing water out with compressed air.

I'd suggest when you go flush out the system that you remove the strainers and flow restrictors from the faucets and remove the shower heads (including the outside shower). This will allow larger particles to exit with the removal of the restrictions.

If there's a lot of mineral build up soak the parts in white vinegar.

[LHaven]

There must be more crude in there so next time we use the trailer, I am going to run city water with the low points drain open and see if more stuff gets flushed.

As long as you keep in mind that running city water isn't going to introduce any water into your fresh tank (unless you have a rig with one of those special valves that lets you do that).

[wanderbird]

So I de-winterized the trailer today. Filled the water tank, flushed the hoses with city water using the low point drains. Turned by-pass to ON so now water is flowing into hot water tank. Turned on the pump to pressurized the system, all seems OK. I ran the water for a few minutes and the pressure was good at first. Running it for a few times, the pressure is back where it was last winter. Weak. The pump is working fine, turns off when it is supposed to. Water pressure is fine on city water. But on just the water pump, there is very little pressure anywhere even tat the outside shower, which is the first outlet.

Can there be a leak at the intake that is causing it to lose pressure? but if that is the case, why would the pump stops if there is a leak? I am baffled. I want to solve this myself before taking it to the dealership and spending money on it. Any other ideas/solutions to try?

[JRTJH]

OK, is there a difference between the "city water pressure/volume" and the "pump water pressure/volume" ???

If there is, are you using a water pressure regulator with your city water connection??? Most of us that do use an adjustable water regulator set it at 45-55 PSI. Also, the "tube type water volume restrictor" type is not a true regulator and won't protect your trailer system from excess pressure damage.

If not, the "issue" may not be a problem, it may be a significant difference in water pressure provided by the city water source (sometimes upwards of 100 PSI/3-5 GPM) and the onboard water pump (typically regulated at 35-45 PSI/2.5-3.5 GPM)...

From what I've read (quickly scanning back over the thread) you have "strong water pressure on city water and not as strong water pressure on the trailer pump"... Could this be a matter of "you get out what you put in," meaning the city water pressure is significantly higher and the RV pump just can't produce that much pressure/volume ???

[bobbecky]

So I de-winterized the trailer today. Filled the water tank, flushed the hoses with city water using the low point drains. Turned by-pass to ON so now water is flowing into hot water tank. Turned on the pump to pressurized the system,all seems OK. I ran the water for a few minutes and the pressure was good at first. Running it for a few times, the pressure is back where it was last winter. Weak. The pump is working fine, turns off when it is supposed to. Water pressure is fine on city water. But on just the water pump, there is very little pressure anywhere even tat the outside shower, which is the first outlet.

Can there be a leak at the intake that is causing it to lose pressure? but if that is the case, why would the pump stops if there is a leak? I am baffled. I want to solve this myself before taking it to the dealership and spending money on it. Any other ideas/solutions to try?

Why are you turning the water heater bypass ON? And, are you leaving the bypass valve turned ON? You only need to turn the bypass valve to ON when you are winterizing the plumbing, all the rest of the time, the bypass valve should be turned OFF. What is the rig you have, model and year?

[flybouy]

The statment that the pressure is fine with the pump initially and it shuts off THEN the pressure drops off while the pressure is fine on city water makes jo sense to me. If the pressure switch is working properly then it should start the pump if it's turned on. If the pressure drops then the pump should run.

[akmk81]

Could there be a kink in the hose from the FW tank to the pump and when the pump runs for a bit the hose collapses? Just a thought.

[wanderbird]

Could there be a kink in the hose from the FW tank to the pump and when the pump runs for a bit the hose collapses? Just a thought.

Ding Ding we have a winner! Seems the guy who put in the hose cut it too short. I traced the line back to the intake and found a crimped hose with a 90 degree turn. Problem solved!! Thanks!!:bow:

When we bought the trailer- we noticed the owners had some water cans in the bathroom and thought they were into dry camping a lot. I suspect they had the same issue and never bothered with it.

[akmk81]

Glad you got it fixed!!

[GAC41]

Make sure your valve settings are set for use or dry camping, if you leave it in the fill tank settings you will loose pressure.