Bob Jones

Just my .02 - if freezing is not an issue I would leave the black tank full of fresh water and put a Green Gobbler in it. I would use that time to get all the crud out of it. I've found, when flushing the tank, even leaving it full with fresh water over night gets even more out. But I'm a little weird that way 🙂

You're telling me. But now she pays for half of it!

Hi Don - I have no idea how to clean those. My guess is that you can't really clean them 😞

Don't give her any more ideas....she's 72 or 73 !! It's all I can do to keep her hands off me 🙂

*Delete*

*Delete*

*Delete*

*Delete* 😞

The 'new' pump is a Shurflo 4008-101

It was free! In fact, the old owner (the widow across the street) was just over for coffee and I told her that the folks down in the states told me I should ask for a refund! 🙂 MODERATORS EDIT. After researching, the pump and water system is maladjusted and not operating within the manufacturer’s specifications and operating instructions. It is recommended that the system be returned to such. One of the tenets of the forum is to prevent future readers from misinformation that could damage the MH or cause injury. It is recommended that the settings be returned to the normal operating range and then advise if there are still issues. That was why it was originally removed from service. It was effectively new but the fresh water tank was self-filling. So I installed a new pump for her and took the old one with me as a spare. I had already installed a nice brass check valve on the line for just such an occasion. Today I readjusted the pressure in the accumulator as it was way off. With the old pump, which came on at 40 PSI, I had the accumulator at 38 PSI. I have the 'new' pump set up to come on at 52 PSI and shut off at 76 PSI. So the accumulator is now @ 50 PSI and the pump, of course, still does it's little twitch. Nice pump, otherwise. Very nice. Quiet and powerful. Zips right up to 76 PSI without a complaint. Mind you, it's being fed good power.

That seems like a sound suggestion so I took the pump out and cleaned it up with compressed air etc. It was like new, and I can verify that the pump head is not leaking. I also pulled and cleaned the check valve. I sealed it up perfect and reinstalled it and....same thing 😞 But at least I know the pump is 100% sound. It shouldn't be air as I'm pretty sure I've gotten rid of all of it. I think I tried that already but can't be sure. I'll try again tomorrow. Also, I think I will check the pressure on my accumulator. It might be way off because this pump seemed to come on at a much higher pressure than the old one. I attached a video of what it is doing. That's why I call this pump 'twitchy' 20221002_182513.mp4

Now I get it - thank you. I had no idea the turbo fed the compressor but it makes perfect sense and also explains the turbo saver valve function.

It could be. I haven't run it long enough to see what's what. I might be worried about nothing since it's effectively a free pump. I don't have water filters but it's an interesting idea since it would tend to indicate back-pressure could be causing it. I might have to just call the 'new' pump twitchy and ignore it 🙂 It did leak back into the fresh water tank on the unit I pulled it from but I do have a proper one way valve on the line so in my mind that really shouldn't matter.

Hi Guys! My excellent cheap water pump finally died after 5 years or so (Flow Max DS-01230-D2) so I installed a slightly used pump that I got off my neighbor because it was filling her fresh water tank over time. In my case, I have a high quality in-line check valve, so I was not concerned about her original issue. The 'new' pump is a Shurflo 4008-101 which is a bypass pump design. It's working quite well, very quiet, and I've got it up to 75 PSI and working like a top. Only one thing. Every few seconds it very briefly pulses on then off. Just for a fraction of a second. This is when there is no water demand and the motorhome system has ZERO leaks. Ie, it will hold pressure forever. Any idea why it would pulse every few seconds for the briefest amount of time when there is no demand?

I still don't understand what the turbo has to do with the system. My understanding is that the compressor runs off the engine, is lubricated by engine oil, and pumps the air into the dryer assembly where it removes moisture and oil etc to ensure clean dry air to the braking system. But...I know little about it, that's for sure! I got a chance to go in there today. So...prior to 'repair' the symptom is that that air dryer was continuously venting out the Purge Valve as the air pressure rose and would not expel air at the 120 PSI cut out as it should. I took off the lower housing and pulled the Purge Valve from the system. It did not look that bad. The bore that it rides in also did not look bad. Nevertheless, I cleaned all the residual lubricant from the bore and then took the valve and dropped it in the ultrasonic cleaner for 30 minutes. I then dried it off, lubricated it, and the bore, with dielectric grease, and put it back together. I then fired up the unit and there was zero air escaping until it reached cut out (120 PSI). I did a couple of cycles and what I noticed was that after the valve 'found its place' as it approached cut out it would leak a little and then reach cut out with the normal woosh and expel moisture. Can anyone confirm for me that it should bleed NO pressure until it reaches cut out? So...it's much better and that confirms that the issue is with the Purge Valve. At this point it's hit or miss with respect to having a perfect seal but it is operational. A Purge Valve kit for these unit is pretty cheap so I will order one in rather than install new O-rings and try to 'repair' the existing one further. Here's some pics for those interested. As always, many thanks to everyone that has responded!

I read that in the document Jeff attached, which was very helpful. But I still don't get, at least with respect to the turbo saver. My Haldex unit appears to have all the same features.

Thanks guys! I'm looking through my docs and mine is a Haldex Pure Air Plus dryer unit. I was in there before some years ago to install a service kit and I pulled out my docs and found that I had printed off a troubleshooting list and parts list 🙂 Apparently you can pull the purge valve and clean it or install a purge valve kit. The kit is about $55 USD from the looks of it. I think I'll pull it in the next few days and see what it looks like inside. Many thanks for the tips! I'll post up a pic when I get in there if I find something interesting. Does anyone know what the 'turbo-saver' does? I have no idea how the turbo would relate to the air dryer.

Hi folks! I noticed a while back that the air pressure was dropping quite quickly on the unit. Today I had it running and I noticed that there is air coming out of the bottom of the air dryer at a continuous rate. In the past it would pump up to ~120 PSI or so and then vent briefly. Now it leaks continuously out the bottom of the dryer vent. It's been some time since I looked at the air dryer, any ideas?

It runs on liquid propane. I do have the service manual but was hoping to find some of the most common issues. I'm guessing not many have the propane genset.

*Delete*

If you mean your water pump, and the city/fresh valve is set to fresh water tank, then I would say yes, you have a leak as the pressure is bleeding down.

Thank you, I went that route because I could get it quickly and cheaply locally. It worked like a top! So clearly suburban and Dometic use the same size holes ! (4 ")

Yeah, I was a bit late on my reply! I meant to get at it earlier but I was busy fixing the water system on my Dad's unit. It's new and I had to re-route all the electrical/water/propane lines going into the slideout. I answer anyway, even if late, for the sake of others referencing this thread in the future even if I missed your boat 🙂

There are typically two reasons for the fresh water tank to self-fill. One is the check valve in the water pump is leaking allowing park water to flow past it and into the fresh water tank eventually over-filling it. This is why I suggest always installing an in-line check valve (not from an RV store). You can get them on Amazon. Of you do this, get a 3/4" valve and use adapters to bring it down to 1/2". This way it will not be a flow restriction. The second place they leak is the City-Water valve. This is typically a ball valve, often hard to replace. Debris can be stuck in it. I suggest removing the handle and flattening the flanges that prevent it from being turned 360 degrees. Then you can turn it around while under park pressure and hopefully it will clear up. In my specific case, I replaced it with a new one and it still leaked. Turns out, if I turn it to the 2 o'clock position it then seals. With respect to the water pressure going back out the city port, this is because the factory check valve, typically next to the City/Water valve is leaking. This too can be difficult to replace. To address your issue I suggest you do two things. Buy TWO 3/4" check valves, put one in discharge line from the water pump and put the other on the inlet side of the City/Water valve (where you attach the hose). This will cover both of your problems. Hopefully you won't need to replace the City/Water valve as they can be a pain if they have PEX lines and copper crimp rings going to them, but it's dependant on the design of your specific unit. PS, I have now put wire mesh hose washers in the city water feed line and also the black tank flushing line in an effort to prevent the odd tiny rock or whatever from going through the plumbing. Hope this helps.