Adding New Low-Point Drains for Alde and Alde Flow

rhyno

Sorry for the long post. We would like some help figuring out if we could/should add secondary Alde low point drains.

Background:
We purchased a regular coil mattress with breather pad underneath. This is wonderful for sleeping but crazy heavy when we have to lift any of the access panels under the bed. We bought this mattress thinking we would not need to access the Alde cabinet very often. Boy were we wrong!

Issue:
Our 2021 400 has the Nautilus system with Hot/Cold low point water drains. The Alde and Alde Flow low point drain valves are under the bed. For some reason, we have had issues after towing to each site since day one with water hammer noise that includes the need to purge the Alde drains until the noise settles out. This also happens sometimes if we have to refill with water mid-trip. All connections are tight - the pump has never run while camping unless we open a faucet; if we leave the camper sitting at home with the pump off between trips, it doesn't run a bit when we turn it back on. I figure these are good indicators that there are no air or water leaks. At any rate, after about 10 camping trips, we trying to see what we can do to minimize the amount of time spent heaving up the bed panels and wedging in 2x4s to prop them while fiddling with the Alde valves. 

Proposed Solution:
1. Tap into the two Alde lines by adding a T connector to each that goes through the floor with valves placed underneath the camper. Seal up the holes with caulk in the Alde area as well as underneath the camper.

While this will be a bit of an undertaking, so is getting under the heavy bed during every trip. Before I dig in, would this even work? Is there an easier way to tap the Alde lines for secondary drains that would be more accessible? Am I missing something with why we have this water hammering issue in the first place?

subkron

I also was thinking about this. I thought just opening the hot and cold drains after a trip was sufficient, until it was mentioned here and I confirmed that there is still water in the Alde. When I opened the yellow flappers (after the hot/cold was drained) the system drained for 3 or 4 minutes.

One thing I thought was to take a hole saw and drill a large hole in the right side of the Nautilus compartment. I think is entirely possible for me to access the flappers through the hole but I was going to try on a scrap piece of lumber to see angle/penetration before I commit. It would be easy enough to put a cover on this access.  This way I can easily get at the existing valves from the outside while I am dealing with the other valves and not introduce additional points of failure (more connections) and not need to raise the bed to drain the system completely.

rhyno

@subkron - That was my initial plan, to cut an access hole in the Nautilus cabinet and reach through to the Alde drains. Then I thought about running auxiliary drain lines into the side of the Nautilus cabinet, and out through the bottom similar to how my hot/cold drains are run. There's definitely more than one way to skin a cat here.

Binghi

How about drilling access holes directly above the flapper valves through the plywood bed platform? You still would have to lift up the mattress, but you wouldn’t have to pull the platform.

subkron

That may work. We are using the froli which we find works fine for us, may be a bit troublesome to deal with that.

Sharon_is_SAM

@rhyno - is the water hammering from the water pump or something else?  Are you adding an air cushion in the Alde?

rhyno

@Sharon_is_SAM It does calm down once I open the Alde boiler valve for a bit, and then the Flow valve to create the air cushion, so I am thinking that is the source of the water hammer issue.

Sharon_is_SAM

@rhyno - Where is the water pump in the 400?  Are you sure you just don’t need to adjust or replace the pump?  Have you spoken with anyone at Alde?  

Here is a video that adds an additional step to adding air to the air cushion:  https://youtu.be/yxjsHMQ_qkk

Also, with a full fresh water tank, if you hook up to city water, fill the Alde tanks, then disconnect from city water and then run your pump, does it still hammer?  If so, it seems like the pump is the culprit.

rhyno

@Sharon_is_SAM - thank you for the tips. The pump location is circled in red. The video you referenced is the one I use, so I'm good there.

I stepped through my fill process and whether I first fill the lines first with city water or pumped water, I get the same issue while running the pump from the holding tank until I create the air cushion for the boiler. It seems my unit must have the air cushion or I'll have the water hammer issue so I'm not sure if replacing the pump would do the trick. I've reached out to Alde to ask about that.

1.    Fill fresh water tank (optional: and pressurize lines with city water)
2.    Turn on pump
3.    Open/close outdoor shower sprayer to purge air until water flows smoothly
4.    Open/close kitchen sink faucet, then shower, then bathroom faucet, then toilet until water flows smoothly

At this point I have the water hammer issue and the pump is running more loudly than normal

Create Alde Air Cushion
5.    Turn off pump
6.    Open kitchen hot till water stops, leave open
7.    Drain off the Alde boiler (forward valve)
8.    Drain off Alde flow (back valve) (this isn't referenced in the video but seems to help with the noise as well)
9.    Turn on pump till water flows again and hammering noise settles out.

Denny16

Another another fix for the water hammer issue, is to install a accumulator tank on the output side of the water pump.  This will but an air cushion on the water line at all times, and reduce pump cycles.
 Cheers 

Sharon_is_SAM

Another question.  If you only run cold water, does it still hammer?  That would indicate a pump problem, not an air cushion problem.

rhyno

Good point @Sharon_is_SAM. It's Hammer Time, hot or cold, but the air cushion step settles out everything. Maybe the accumulator fix is the next step.

I still would like to make the Alde valve mods so we won't have to fuss with the bed panels to create the air cushion. 

Sharon_is_SAM

If it were me, I would try to adjust the pump settings or replace the pump.  Yes, the air cushion helps to moderate pressure changes due to expansion/pulsation, but a reduced air cushion is not the cause of the hammering.  I worry about the impact on your plumbing and Alde joints.  Here is a link that includes a discussion and YouTube video about adjusting the pump.
https://tab-rv.vanillacommunity.com/discussion/5588/pump-problems/p2

Denny16

When you fill the water system after normal draining at the end of a camping trip, the Alde air cushion is restored when the tank refills.  You only need to burp the tank pressure release valves (blue lift up handles) when camping for extend times.  The air cushion in the hot water tank will last three to four days, without any issue.
 Cheers 

rhyno

I adjusted the pump pressure without any luck. I then tried to work my way back from the pump and I think I figured out the issue. The strainer basket always has a tiny, half a pea-sized air bubble when I first turn the pump on, presumably from air in the line until water flows into the pump. It won't fully purge that little bubble due to the design of the strainer basket having a lip in the cup closest to the pump inlet. It never gets bigger, and no matter which way you turn the basket, the bubble remains...BUT when I set the Alde air cushion, I think the negative pressure created by that process through the pump allows the bubble to escape.

I tested this several times, and each time, the bubble disappeared as soon as the air cushion was set, then the pump ran smoothly and quietly.
I had a spare strainer basket and tried it with the same results.

Next, I removed the strainer basket from the line completely, primed the pump, and the noise and vibration settled out as soon as I ran the fixtures, without having to set the Alde air cushion first. I'll still need to set the air cushion for best practice, but no longer will need to rely on that to quiet the pump. I then installed a whole house filter (with a purge button) on my supply line to keep debris out if the filter going forward. 

Why my particular Tab has always had this problem I don't know since I would assume given the strainer basket design, that eveyone's would have a small air bubble when initially priming the pump. Maybe the vibration was normal and I was just mistaking it for water hammering? Had the pump been located anywhere but under our heads in the bed area I may not have ever thought this was a problem to begin with At any rate at least I don't have to dig under the bed every time I top off the water tank anymore. I may still try to figure out how best to make more accessible Alde drains, but it isn't as pressing of an issue anymore. 

Thanks everyone for your suggestions along the way! 

rhyno

@subkron - Let us know if you end up drilling a hole in the side of your Nautilus compartment and what you used to cover it back up. Now that I've taken a closer look at the plumbing, I'm back to thinking your idea would probably be the most straight-forward.