Too much water pressure buildup in city position through Anderson Kantleak

[McDaniel]

High water pressure buildup
We just purchased a 2017 Heartland Big Country September 2017. We are new to the RV life yeah!!
Here’s my problem when hooked up to a water source and I select the city for our water supply I have noticed the water pressure will build to 70 PSI or higher if I was not monitoring it (SCARY)

first course of action was replacing my new water regulator with pressure gauge. I went through Amazon and bought a more expensive better model adjustable with pressure gauge. With no change to the pressure buildup

After more testing I found that both regulators would hold pressure between 50 and 55 psi if I use a hose bib or placed the Anderson Kantleak on normal position. this showed that both of my pressure gauges were accurate and working properly

Next step was to call Anderson I spoke with Mike (great guy very knowledgeable) I followed the steps to troubleshoot the system to find out there was a bad O-ring in the valve selection body 1 of the O-rings was completely severed. I ordered the replacement part at $65 and replaced it. no change I still have pressure buildup, more troubleshooting with Mike from Anderson we found that the check valve in my water pump was bad

My water pump is a Shurflo MN 4008 3.0 GPM I ordered the replacement check valve from my local RV supply $13 shipping included replaced a check valve no change water pressure still building. I called Shurflo spoke with a gentleman named Mel ( Nice guy very professional) he sent me a new head at no charge. Replace the head today I still have water pressure buildup any advice or help would be greatly appreciated

 

[danemayer]

Hi McDaniel,

Welcome to the Heartland Owners Forum.

I'm a little confused by what you're describing.

I have noticed the water pressure will build to 70 PSI or higher if I was not monitoring it (SCARY)

..... After more testing I found that both regulators would hold pressure between 50 and 55 psi if I use a hose bib or placed the Anderson Kantleak on normal position. this showed that both of my pressure gauges were accurate and working properly

.....we found that the check valve in my water pump was bad

Other than puzzling pressure gauge readings, are you having some other problem? How did the water pump check valve problem come up?

 

[Gary521]

Where are you placing the water pressure regulator? You mentioned something about a hose bibb. What are you referring to? The hose for the water is screwed into a bibb.

 

[McDaniel]

Hi Danemyer,
Thanks for checking in, I found the check valve issue when troubleshooting with Mike a representative from Anderson Kantleak.

 

[danemayer]

Hi Danemyer,
Thanks for checking in, I found the check valve issue when troubleshooting with Mike a representative from Anderson Kantleak.

The only problem I'm aware of that's caused by a pump check valve failure is that the fresh tank fills up by itself. Is that what's happening and is that why you started looking at the water pressure?

 

[TedS]

McDaniel, where are you measuring water pressure? Heating water in the water heater will raise system pressure as the hot water expands, especially if there is no air bubble in the water heater.

 

[McDaniel]

Hey Gary521,
Gary thanks for the response, as I mentioned in my opening letter I’m new to RV life and some of the terminology that goes along with RV life. when I use the term hose bib I was talking about a hose nozzle that’s all I had that was handy to stop the flow of water to check for buildup of pressure. Answer to your question I first installed new regulator on the trailer at the water inlet or the hose bib, when I had problems with pressure I moved it to the faucet, the problem is not the regulator when I have my selector on city and running water in the sink shower or toilet pressure does not exceed 48 PSI when water is not in use pressure builds at a rate of about 2 psi every five minutes or so. I was hoping that somebody in this forum could help me with this issue

Thanks again for your interest

 

[danemayer]

Let me ask another way. Why do you care what the pressure reading is?

 

[cemill]

Can you just use a 45LB pressure regulator at the fresh water source?

 

[Gary521]

We are all trying to understand your problem and trying to help. If I understand you correctly, you originally had the water pressure regulator attached to the water inlet on the trailer. This initial regulator did not have a pressure gauge. Question: if it did not have a pressure gauge, how were you reading pressure and where were you reading pressure at? The second water pressure regulator DID have a pressure gauge. In the initial hookup, were you reading pressure between the water spigot and the water regulator? If so, this pressure is not relevant to pressure inside the trailer.

As far as terminology goes, it does not matter as long as we know what you are talking about. Normally a hose bib or bibb is that thing that is attached to the end of the water pipe with the twist thing on the top that shuts off the water and regulates water flow. Some people call it a spigot. For example, a hose bibb is attached to the wall of your house. The "water inlet" is that fitting that the hose is screwed into at the trailer. If somebody has another name for it, I am not aware of it.

 

[McDaniel]

Good morning Dan,
yes we did have freshwater tank overflow.

Right now it’s more important for me to control the water pressure isssue. Hopefully replacing the water pump head rectified the problem of fresh water tank overflow as you said in your reply the check valve controls that issue, because of the high water pressure I’m experiencing I do not want to use city connection until my water pressure is under control for that reason I don’t know if my freshwater tank will overflow or not. The main problem here is water pressure buildup I do not want to damage my system.

This is what I’m sure of. Water pressure builds up when the Anderson valve is in the city position only, I can have water pressure on and my Anderson valve in the normal position and water pressure will hold 48 psi, as soon as I switch to city selection water pressure builds up. Mike the service rep at Anderson told me there is no way his control valve could cause increase of water pressure, their unit could only cause a decrease of water pressure. This is the reason we looked at the check valve in the water pump

Dan is it possible this RV has had water pressure issues from the beginning and it blowout the check valve in the water pump, I have always used a water pressure regulator BUT I do not know if the prep team were I bought my RV has the same quality control,

 

[McDaniel]

Good morning Gary521,
I’ve always used a regulator with a pressure gauge so I can monitor the amount of pressure going into my RV. The problem of water pressure started when my Anderson control valve is in the city position ONLY water pressure will build up slowly.

Originally I did have my water regulator with pressure gauge attached to my water supply in-lit on my RV this was recommended from the RV parts supply counter person. His reasoning for this was people are always replacing their regulator because they are left behind when they disconnected the hose.

 

[danemayer]

Good morning Dan,
yes we did have freshwater tank overflow.

Right now it’s more important for me to control the water pressure isssue. Hopefully replacing the water pump head rectified the problem of fresh water tank overflow as you said in your reply the check valve controls that issue, because of the high water pressure I’m experiencing I do not want to use city connection until my water pressure is under control for that reason I don’t know if my freshwater tank will overflow or not. The main problem here is water pressure buildup I do not want to damage my system.

This is what I’m sure of. Water pressure builds up when the Anderson valve is in the city position only, I can have water pressure on and my Anderson valve in the normal position and water pressure will hold 48 psi, as soon as I switch to city selection water pressure builds up. Mike the service rep at Anderson told me there is no way his control valve could cause increase of water pressure, their unit could only cause a decrease of water pressure. This is the reason we looked at the check valve in the water pump

Dan is it possible this RV has had water pressure issues from the beginning and it blowout the check valve in the water pump, I have always used a water pressure regulator BUT I do not know if the prep team were I bought my RV has the same quality control,

So...

Water pressure starts with the force of the water coming out of the campground faucet. Nowhere in the system is it going to be higher than the pressure at the campground faucet. But the campground faucet water pressure can go up or down depending on who else is using water, or if a pump upstream from the faucet is running.

If you put a pressure gauge on the campground faucet, you'll get a reading on the pressure at that moment. It may go up or down in the next moment as things change upstream. While municipal water supply usually has a pretty stable water pressure, campground water pressure is more likely to vary.

If you attach a hose to the campground faucet and move the gauge to the end of the hose, the pressure reading will be the same as when you measured the pressure right at the campground faucet. In both cases, you're reading static water pressure because no water is flowing.

If you put a regulator at the faucet, and attach the hose to the regulator, and put the gauge at the other end, the new reading should reflect the setting of the regulator, unless the campground water pressure is lower than the setting on the regulator. Still static pressure.

If you remove the gauge and leave the regulator in place, and then attach the hose to the trailer's water inlet, normally, the water pressure at the water inlet will be the same as you just read on the gauge, because, again, no water is flowing. It's still the static pressure you read at the faucet or after the regulator.

But, with a leak in either the Anderson Valve, or in the water pump check valve, or both, the pressure will drop a bit. With water flowing inside the trailer, the pressure reading (if there's still a gauge somewhere) becomes a dynamic pressure reading, which should be a little lower. The more water flow inside the trailer, the lower the pressure will drop. When the leak stops, pressure will climb again, but won't exceed the regulated (or unregulated) pressure. Your water pressure is limited by the pressure coming out of the campground faucet.

This may all be pretty confusing. But to answer your question, your trailer doesn't have a pressure problem that is increasing water pressure. It did apparently have a leaky Anderson Valve and a partially open water pump check valve, both contributing to the fresh tank overflow. Both problems are pretty common. The Anderson Valves have had problems of this nature for years and have had several redesigns. The water pump check valve can get crud stuck in it, allowing water leakage backwards through the pump and into the fresh tank, especially if you're not filtering your incoming water.

Take a look at our owner-written Water Tank Fills by Itself user guide, along with the Water Systems User Guide. I think they may clear up a lot for you.

 

[Gary521]

Yes, I too have left the water pressure regulator at the campground so your parts guy was somewhat correct.

Try this. Put the pressure regulator on the water spigot. Attach the hose to the regulator. Attach a spray nozzle to the other end of the hose. Turn off the spray nozzle. Turn on the water. See if this method shows an increase in pressure over time at the regulator. This will definitely show if the pressure regulator is working properly and isolating it from anything inside the trailer. I cannot think of anything in the trailer that would increase pressure. ( see next sentence )

I am not sure of this so maybe somebody else could chime in. There is a check valve on the inlet to the water heater. If this check valve were defective or missing, would this allow pressure from the hot tank to push back into the system?

 

[TedS]

There is a check valve on the OUTLET of the water heater. There is a check valve on the trailer fresh water inlet to prevent backflow from the trailer to the campground water system.

When all the faucets are closed the trailer water system is a closed system. When heating water, the water expands trying to go both out the water heater outlet and back out the tank cold water inlet. There is no place for the water to go so the whole trailer water system pressure increases. It can increase until something fails, or most likely, the relief valve on the water heater opens at 150 psi.

 

[danemayer]

There is a check valve on the OUTLET of the water heater. There is a check valve on the trailer fresh water inlet to prevent backflow from the trailer to the campground water system.

When all the faucets are closed the trailer water system is a closed system. When heating water, the water expands trying to go both out the water heater outlet and back out the tank cold water inlet. There is no place for the water to go so the whole trailer water system pressure increases. It can increase until something fails, or most likely, the relief valve on the water heater opens at 150 psi.

The water heater usually has an air pocket that compresses, which usually prevents weeping from the temperature/pressure relief valve, and would also minimize an increase in water pressure. And of course the thermostat limits the heat generated pressure increase as well. If it didn't, the pressure buildup you're describing would cause water to shoot out every time a hot water faucet was opened. That would be abnormal.

But if your theory is correct, for the pressure increase to show up on a gauge outside the trailer, there would have to also be at least a partial failure on the water inlet check valve. Otherwise the higher pressure water wouldn't get outside the trailer.

The heated water expansion theory could be tested by releasing any excess pressure at the water heater temperature/pressure relief valve and noting whether it leads to more than a momentary reduction in the reading on the gauge.

If you try this, use a pair of pliers to open the relief valve as the water that comes out will be very hot.

 

[TedS]

Just open any faucet, hot or cold, to relieve water expansion generated pressure. You do not have to open the hot relief valve.
A leaky inlet check valve allowing water to expand back to the campground will not show an increase in pressure unless the water pressure regulator prevents reverse flow. Otherwise water just pushes back into the supply.
Keeping the bubble in the tank to accommodate expansion requires attention to regularly 'burp', release water, by opening the relief valve on the water heater tank.
Water heating to the thermostat 140 F setting will expand enough to generate high pressure, if there is no bubble, expansion space, in the water heater.

 

[SLO]

I’ve reread these post several times and you have an interesting problem. Probably an easy problem to fix just hard to figure out from afar. Here’s what I know. I proper working PRV will not let pressure go above it’s set point. Water heaters should not have an air space in them for expansion. Thermal expansion, when the water heater is heating, will go into the cold line connected to the water heater. If there is a check valve in the cold line, close to the water heater, pressure will build up in the water heater. This can trip the T & P valve if pressure gets high enough. If your pressure increase is in the hot line only then your problem is related to the water heater. I have seen expansion tanks installed on RVs before. If your water pump is on when you’re hooked up to city water this could increase the pressure but only if the water pump in malfunctioning. Also, I wouldn’t use the T &P valve to relieve pressure, it can cause premature failure of the T & P valve. I am also curious, if your PRV gauge is connected to the hose bibb how do you know the pressure in the trailer is going up to 70 psi?


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[danemayer]

From the Suburban manual, instructions on maintaining the air pocket (emphasis added):

WATER WEEPING OR DRIPPING FROM PRESSURE
RELIEF VALVE
You may experience water weeping or dripping from your water heater’s Pressure
and Temperature (P & T) Relief Valve when your water heater is operating. Water
weeping or dripping from the P & T Valve does not always mean the P & T Valve
is defective. As water is heated, it expands. The water system in a recreational
vehicle is a closed system and does not allow for the expansion of heated water.
When the pressure of the water system exceeds the relieving point of the P & T
Valve, the valve will relieve the excess pressure.

Suburban recommends that a check valve not be installed directly at the inlet tothe water heater tank. This will increase weeping of the pressure relief valve.
WARNING! Do not remove or plug the relief valve.
One way to reduce the frequency of this occurrence is to maintain an air pocket
at the top of the water heater tank. This air pocket will form in the tank by design.
However, it will be reduced over time by the everyday use of your water heater.
To replenish this air pocket:
1. Turn off water heater.
2. Turn off cold water supply line.
3. Open a faucet in the RV.
4. Pull out on the handle of the Pressure Relief (P & T) Valve and allow water to
flow from the valve until it stops.
5. Release handle on P & T Valve - it should snap closed.
6. Close faucet and turn on cold water supply; as the tank fills, the air pocket
will develop.
Repeat this procedure as often as needed to reduce the frequency of the weeping
of the P & T Valve. If the weeping persists after following this procedure, you may
elect to install an expansion or accumulator tank in the cold water line between
the tank and check valve to relieve the pressure caused by thermal expansion.

If you need a copy of the Suburban Water Heater manual, here's a link.

 

[TedS]

Suburban makes the point, water pressure increases with temperature. By the time the water dribbles out the relief valve the pressure in the water system has gone to 150 psi. How many times does that happen before anyone opens the access door to notice that the valve has dribbled? Overpressure due to heating water may be more the cause of failed plumbing than campground overpressure.