Water pump leak

[Cate&Rob]

TedShowson

I “think” my trailer is plumbed as Ted describes. This could be because I have the Anderson Kantleak water system that actually connects the water heater inlet and outlet to each other and the feed and hot water plumbing to each other in bypass. In bypass, the water heater drain has to be used to drain the water heater (which is how I usually do this).

Rob

[Country Campers]

I thought that just filling the water heater tank, open hot side on a faucet until there is no air in the water, was the proper way to have the "air dome" in the tank? The hot water outlet is lower than the pressure relief valve so the "air dome" is present. If the pressure relief valve is opened it does not produce the "air dome" but allows the tank to fully fill.

Brian

[Yoda]

I thought that just filling the water heater tank, open hot side on a faucet until there is no air in the water, was the proper way to have the "air dome" in the tank? The hot water outlet is lower than the pressure relief valve so the "air dome" is present. If the pressure relief valve is opened it does not produce the "air dome" but allows the tank to fully fill.

Brian

Brian that is the way I have done it for years, run the inside faucet to fill. I only use the PR valve to empty. I sure hope I have that correct.

Thanks Keith

[Jlawles2]

I did just as Keith describes. Never pop the T&P valve and still had pressure rise issues on gas or elect. I got in the habit of waiting about 10-15 min after turning on the HWH and burping the Hot line. This seemed to be the best solution. Just so happens after everything is hooked up and HWH on, the 10-15 min mark was about how long it took me to get the last few thing buttoned up before kicking back to relax.

When hunting, different all together as the unit was already setup. A lot of times, the HWH would stay off until I needed it.

[TedS]

FWIW, Suburban

[howson]

I got in the habit of waiting about 10-15 min after turning on the HWH and burping the Hot line.

I tend to do the same thing. Since I'm so aware of the issue (pressure rise in the system due to hot water expansion) it's like impulsive hand washing--don't have to think much about I just do it.

[TedS]

You can burp either hot or cold. The pressure rise occurs in the whole water system.

[Cate&Rob]

You can burp either hot or cold. The pressure rise occurs in the whole water system.

Opening just a cold faucet would not relieve pressure in the hot side plumbing, because of the check valve on the water heater outlet. Opening just a hot faucet should relieve pressure in the entire system.

Rob

[Cate&Rob]

I thought that just filling the water heater tank, open hot side on a faucet until there is no air in the water, was the proper way to have the "air dome" in the tank? The hot water outlet is lower than the pressure relief valve so the "air dome" is present. If the pressure relief valve is opened it does not produce the "air dome" but allows the tank to fully fill.

Brian

Hi Brian,

I agree with your process for initial fill. If the trailer is used for an extended period of time (weeks) the air in the dome is slowly absorbed into the water. This is where the water needs to be drained down and a source of air provided to re-establish this air “cushion”. You could do this by draining the hot line all the way to a faucet to repeat the initial fill process, but an easier way is to pop open the pressure relief which is right at the air dome location and drain down the water in the water heater, using the low point system drain or a valve on the water heater drain ( which is what I use). When the water system is re-pressurized, the air dome will be re-established at the correct volume.

The important part of this whole discussion is that as the air dome is absorbed, the entire RV water system is seeing pressure spikes far above the inlet pressure regulator (that most think is “controlling” their water pressure). The “fix” is an accumulator tank. The way to know what is going on is a system pressure gauge.

Rob

[Jlawles2]

Cate&Rob Rob, I had issues even on initial fill without letting the air out of the HWH and only filling using the faucets. Without the dome, the pressure rise is probably more pronounced.

I think the issue is pressure of the dome in creases with temperature also thus the pressure spike is still there, just not as bad with the dome vs without.

[Rabbit]

BTW . . . there is no check valve on the cold water feed to the water heater . . . only on the outlet, and it is there only to prevent backfilling of the water heater when in bypass mode.

Rob

Yep, had it backwards.

[BobinICT]

howson TedS Cate&Rob

OK, so update on this situation. Took most of Friday off because we got flu shots and it his us for a day or so.

So, Friday morning, do the open pressure relief valve, open COLD low point drain, nothing came out of the PR valve yet heard gurgling in the tank with the LP valve open, just for a small bit.

Start gas on the water heater, monitor pressure gauge. At 115 PSI small seep starts, at 120, now have droplets on top. Burp hot and cold, pressure goes down to about 80 and climbs to 120 as the tank is heating, some slight water exiting the top of the pump. Burp again and let it be. Pressure maintains about 105 or so, no leakage.

Saturday, no opening of the PR or LP valves. Want to mimic normal operation. Seeping again stars at 115, burp it and call it a day. Put the rig to bed and water pump is off, heat off. Next morning, Sunday, Pressure has maintained about 90 through the night. Start heater on elec, slight seep again at 115. Burp it and leave elec heat and pump on throughout the day. Some wetness on top of the pump but not too bad. Pressure maintains at about 95.

This has been an ongoing issue since we had the replumb done at Goose Island in December and remained through out our winter trip. Just kept a bedpan there and dealt with it.

At this point, the leak seems to have gotten much less. Could have been tightening the screws on top. All and all, just going to roll with it. At least, I know we have a very good closed system. Not like before the replumb as I suspected a leak all along. Pump cycling at times. It was a damaged shower hot soft line I discovered (factory done I'm sure) before we departed for the winter last year and I bandied it to get going knowing we were going to do that replumb on the road.

So, at this point, the rig gets a bedpan under the pump, relocated the water alarm a little and the plumbing is now on circle red X status. (Army aviation, you know what I mean) I can access the bedpan as needed through the access panel I installed. That's what I did for weeks but with the whole access area exposed.

Thanks for all the insight on this thread. Hopefully someone can learn from this.

[TedS]

Thanks for the follow-up. An accumulator can keep your peak pressure 90psi or lower and eliminate the drip. FWIW

[Country Campers]

Since this has been going on since the "re-plumb" I wonder what has changed when the plumbing was done? Do you have before and after pics? Was there any changes to line routes? There has to be something that has caused this issue, burping the system is a small fix that should not have to be done.

Brian

[howson]

So, Friday morning, do the open pressure relief valve, open COLD low point drain, nothing came out of the PR valve yet heard gurgling in the tank with the LP valve open, just for a small bit.

No water should come out of the P&T, or Pressure & Relief Valve when the water is cold and the cold LP (low point) drain is open. What surprised me was the statement, "...for just a small bit". It's a straight shot from the cold water inlet to the cold water LP drain. As the name implies, the LP drain is below the heater so due to Sir Isaac Newton, with the T&P and the LP open, water should drain out the bottom of the camper until the water heater is empty.

I assume city water was turned off prior to doing the LP drain process. After draining some or all the water, applying city water will refill the heater BUT there might be too MUCH air in the system. Running hot water faucets to clear out all that extra air (with all the sputtering and spitting we're all familiar with) stops when the excess air is removed.