Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

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Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

June 03, 2018, 10:58:37 pm

This one took me a while to find. It's very hot here in TX Hill Country, so the roof airs are going making noise and masking other sounds. Starting yesterday first time, when 12 volt compressor ran in basement we could sometimes hear a "thumping" sound every couple of seconds. By the time I could get outside and open compartment it ended.

Note" unlevel site, back end all the way down, front fully lifted for level. May be causing compressor to run more often than usual.

At the same time this started, dash air gauges both tanks began showing 125 psi while parked and Cummins off. In the past, dash gauges always showed 75 psi when parked a few days (12 volt aux compressor previously kept it at 75 psi, or that was just the set point after leak down - one or the other)

"Thumping sound" again at 3:30 am and 4:15 am. waking me up. Finally went outside and unplugged the compressor wiring.

Today I manipulated the air system to get 12V compressor to run and everything was fine. No abnormal noises. Perfect operation. First run compressor brought air gauges/tanks back up to the usual 75 psi after I pumped brakes to bring pressure down and deflated slide bladder then re-inflated. Compressor shut off at 75 psi on dash gauges. Maybe 10 minutes later compressor started again and brought tanks air gauges to 125 psi then shut off. This never happened in the past.

Finally pulled grey cover on the pressure switch on the end of the compressor, and started the compressor that way. "Thumping sound" started and it was the air unloader dumping air every few seconds. Air unloader (or spitter) was hidden behind large wiring bundle and out of sight. Had to feel around to find the air bursts/spits. Air unloader or pop off valve was releasing excess pressure multiple times as compressor ran to long creating more pressure than system designed for.

Pic one air unloader far left (white air line, pull ring on unloader) (pic courtesy Steve Cook archive). This was hidden from view as installed.

Pic two and three the air governor or controller (hidden under grey cover mounted on end of compressor). Pics from other members previous posts:

Compartment has been very hot. Hotter than any time we have owned the coach. May or may not have brought issue to fore front. Maybe related, maybe not.

Theories:
1. Air unloader / spitter doing exactly what it should and protecting system from over pressure. Good to go on unloader.

2. Theory 2: I only need to replace the air governor/pressure switch (pic 2 and 3) . Over pressurizing system, time to replace. Cause and only cause of all issues.

3. Theory 3: In addition, some "one way" check valves in the system *may* be feeding air to main tanks instead of only 3rd air tank from the 12 volt compressor (when it should not?). Note: The switch at drivers left side labeled air tank is off and has always been off since we owned the coach. I cycled it once today for the first time ever.
Air gauges in the past, even after months parked have always shown 75 psi at all times when parked. Seems 12 volt compressor has always maintained the main air tanks at 75 psi even over extended time frames.

Comments welcomed. I need to order the air pressure governor in pic 2 and 3 ASAP and get it installed. I unplugged the compressor for the time being. Best source/price (identical item that will fit under grey cover). Assuming either HWH or FOT best and quickest source. We are at Medina Lake in TX Hill Country.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #1 – June 04, 2018, 07:39:28 am

Check at Lowes/HomeDepot or other local hardware stores, they may have a well pump switch that might be compatible. Possibly a ranch supply store. Need to make sure that it will work on 12 VDC. Might not be the same size or design but should work as well as the original. I think that switch can be compared to a relay that is air operated, so look at the electrical contact points and may sure they aren't arced.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #2 – June 04, 2018, 07:44:26 am

Dan, I have a new pressure switch still,in the box, I will look for a part number later today. Barry B. Replaced his with one that had an on/off/auto lever on the side. Maybe his post might have a part number. I never found one of those butit would have been nice. My pressure switch "sticks". Sometimes the contacts need some encouragement for the thing to start.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #3 – June 04, 2018, 08:32:54 am

Our water well control used to get "sticky" and start to behave erratically. There are a couple of breaker points in it that open and close. With age, they can get pitted and cruddy. Sometimes you can "dress" them with a automobile distributor points file (remember those?), and restore proper function temporarily. You can also mess with the spring tension and sometimes get the control working again. But, as you have guessed, the best solution is complete replacement of the control unit.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #4 – June 04, 2018, 10:56:02 am

on my 2000 (your coach may be different - if you don't have the factory air diagrams in your manual call and get them emailed to you from Foretravel - there is a check valve in the system designed so that the 12V compressor CAN NOT fill main tanks - the duty cycle on the Thomas that I have is too short and would abuse pump. Your coach may have a different system - you likely have a check valve issue if your design is similar to mine

FWIW - The "front" and "rear" (mine are actually both up front with another tank in the rear) main tanks have a "protection valves" (not sure that is the correct term) that will not allow leak down below a certain set point in service of the leveling system - (depending on the leaks you may have in the main system, they may still leak down after reaching the set point - over time)

ON my 2000, the 12V air pump does not have an "unloader" it has an automatic drain that opens when the pump shuts off to drain the small plastic bowl where condensed water accumulates after operation (again, I have a 2000), and a simple pressure switch (on at 60 PSI, off at 90 PSI) is in line to trigger the pump on or off

If you are having check valve issues - you may have some desiccant in the system, or you may just have gotten one with something lodged in it - when did you last service your main air dryer and when you drain your rear tank manually do you see anything visible in the air as it exhausts?

on mine there is a TINY check valve located adjacent to the 12V pump and 5 others in the system, notably one on the output line to that isolates the main tanks from the 12V system with regards to the OUTPUT of the 12V pump.

Good luck, let us know what you find -

again, my coach may be totally different than yours

Tim Fiedler

Sure Start Soft Start - home of SureStart soft starters TCER Direct - home of Generac Approved Aluminum and Copper TCER Composite cable generator-gas-prod - home of X-Riser Gas Risers for PE installation Call me at 630 240-9139
Gen-Pro

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #5 – June 04, 2018, 11:16:03 am

* "the duty cycle on the Thomas that I have is too short and would abuse pump. Your coach may have a different system - you likely have a check valve issue if your design is similar to mine"

- Our 2003 has the larger floor mounted Thomas system. Not sure yet if I have a check valve issue. Will solve the compressor problem (pressure switch) first then look into it.

*"FWIW - The "front" and "rear" (mine are actually both up front with another tank in the rear) main tanks have a "protection valves" (not sure that is the correct term) that will not allow leak down below a certain set point in service of the leveling system - (depending on the leaks you may have in the main system, they may still leak down after reaching the set point - over time)"

- Makes sense. Our coach 2 front main dry tanks don't go below 75 psi even over multiple months.

*ON my 2000, the 12V air pump does not have an "unloader" it has an automatic drain that opens when the pump shuts off to drain the small plastic bowl where condensed water accumulates after operation (again, I have a 2000), and a simple pressure switch (on at 60 PSI, off at 90 PSI) is in line to trigger the pump on or off
- Different design with 2003.

*If you are having check valve issues - you may have some desiccant in the system, or you may just have gotten one with something lodged in it - when did you last service your main air dryer and when you drain your rear tank manually do you see anything visible in the air as it exhausts?

- Coach main air drier last serviced Feb 2017. And well maintained by previous owners as well. No visible discharge of any kind (water, powder, debris) when manually draining the tanks. Even the rear wet tank s clear.

*on mine there is a TINY check valve located adjacent to the 12V pump and 5 others in the system, notably one on the output line to that isolates the main tanks from the 12V system with regards to the OUTPUT of the 12V pump.

- Good info for me to check on

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #6 – June 04, 2018, 11:20:05 am

Dan

Agree, but I doubt that your 12V is designed to fill main air tanks - not sure if you have the factory air diagram but if not I urge you to get it from james Triana at FYT (mine was NOT in my normal documentation - it was sent to me - as I recall it was two different drawings)

Tim Fiedler

Sure Start Soft Start - home of SureStart soft starters TCER Direct - home of Generac Approved Aluminum and Copper TCER Composite cable generator-gas-prod - home of X-Riser Gas Risers for PE installation Call me at 630 240-9139
Gen-Pro

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #7 – June 04, 2018, 11:23:29 am

Quote from: Tim Fiedler – June 04, 2018, 11:20:05 am

Dan

Agree, but I doubt that your 12V is designed to fill main air tanks - not sure if you have the factory air diagram but if not I urge you to get it from james Triana at FYT (mine was NOT in my normal documentation - it was sent to me - as I recall it was two different drawings)

Tim Fiedler

Sure Start Soft Start - home of SureStart soft starters TCER Direct - home of Generac Approved Aluminum and Copper TCER Composite cable generator-gas-prod - home of X-Riser Gas Risers for PE installation Call me at 630 240-9139
Gen-Pro

I have not yet looked through all my documentation for air diagram. Probably already have it, if not I will seek it out. I'll be in NAC in early August, or contact James sooner. (Edit: I do have all the air diagrams for this coach).

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #8 – June 04, 2018, 11:38:14 am

On my coach, also an 03, the "air tank" switch on the side consul, opens a solenoid valve that connects the 12 volt compressor [which is rated continuous duty] directly to the wet tank. You can fill [to 90 psi] the wet tank and thus the two dry tanks, but it will take a long time.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #9 – June 04, 2018, 11:17:29 pm

Dan, this is the pressure switch I got from FT.

Square D by Schneider Electric 9013FHG2J27 Air-Compressor Pressure Switch,...

A lot less than I paid at FT

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #10 – June 04, 2018, 11:51:24 pm

Quote from: Roger & Susan in Home2 – June 04, 2018, 11:17:29 pm

Dan, this is the pressure switch I got from FT.

Square D by Schneider Electric 9013FHG2J27 Air-Compressor Pressure Switch,...

A lot less than I paid at FT

Thanks Roger, I was just researching part numbers on the HWH site unsuccessfully.

"100 psi Set Off, 20 psi Fixed Differential" (80 to 100 psi) Great price on this one.

Edit: I should have thought of this earlier. I just pulled the cover off of the pressure switch. Inside cover says Pumptrol SquareD 9013FHG2, 100 psi.

Couple of quick searches:
9013FHG2J27 without lever
9013FHG2J27M1 with lever

With lever: Square D by Schneider Electric 9013FHG2J27M1 Air-Compressor Pressure Switch,...

I ordered the one you linked without lever, Amazon Prime delivery June 7 to General Delivery. Hopefully Amazon will send USPS not FEDEX or UPS.

Thanks for that Amazon link!!

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #11 – June 07, 2018, 08:46:19 pm

Switch installed. In photos, old one still wired, new one next to it.

Also tested the air tank switch at drivers left side. Working as it should with the new pressure switch. Tested by pumping down the brakes with the air tank switch both off and on. 12 volt compressor refills the two tanks with it on, does not when off.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #12 – June 09, 2018, 08:52:04 pm

Time to update this thread. The new pressure switch mounted at 12 volt aux compressor did not resolve the problem. The old one looked fine, and the new one is not the solution. Only $20 part, now have a good spare in the old one.

Environment issue: Unlevel site we are in. Back end all the way aired down, front end lifted all the way (maxed out). No "excess slope" light though. Yellow light for low front end just barely out at full lift. (potential this is the main problem, more to follow further down).

Issue: the air tank switch "appears" to work correctly via solenoid by compressor on quick tests. Pump brakes down, check gauges on dash. With air tank switch off, gauges stay put. Turn on air tank switch, compressor airs tanks to 75 psi as shown on gauges (I turned pressure switch down to max 75 psi due to issues).
All looks good. Turn air tank switch off. Later compressor runs again, check gauges, tanks now at 100 psi. 5 am compressor runs again, air relief valve starts loudly releasing air in spurts. Hit HWH reset to shut it down. Check air gauges - 125 psi. (again, the air tank switch is actually off). Pressure relief valve on aux compressor in basement bay releases air loudly at 125psi.

2003 air compressor and wiring and "air tank" solonoid combining air tanks is a bit different than earlier years.

Two potential issues:
First, solonoid # 2 that airs the front tanks via aux compressor operates, but has slow leak through that is filling the two tanks. The compressor mounted air pressure switch should still shut down the compressor way before 125 psi. I have rebuild kits of Orings and small piston, so can rebuild that solonoid. See pics for solonoid just to left of grey pressure switch cover, and diagrams of solonoid 2 location.

Second, old post from forum search, reply # 11: "Air Tank" Switch
"Right after we purchased our coach we went to Nac for the Motorcade Ladies Driving School. I was assigned a spot on the very-sloped back-side of FT's parking area in Nac, I left the coach immediately after parking, and (I thought) level. I came back :30 minutes later to what sounded like a shot-gun being discharged every 15-20 seconds. After running around in little circles for a few seconds flailing my arms, I realized I could hear the electric compressor running. I opened the bay where it's located to find what I was later told is the over-pressure pop-off valve on the air-suspension system discharging. I quickly turned the HWH "off", moved the coach a bit to make it more level, and everything worked as-advertised. James Trianna later told me that if you park on a slope that exceeds the limits for the HWH, "occasionally" the system will try to level until it over-pressures, which pops the valve (forward street-side bay on my '98) making the "very" loud report. It's never happened again. "

This "sounds like" exactly what is happening with our coach. "Perhaps" the HWH control boards have a bit of programming error that tells compressor to run beyond the mechanical limits of the pressure switch in an attempt to raise the front end further than design specs??? I have to admit I don't understand how it can bypass the mechanical/electrical limit of the pressure switch, but the description does fit our circumstances near exactly.

For tonight I uplugged the compressor. We like our site and don't want to pick a new one. We have FHU 50 amp, shade, large space, and good sat shot. Tomorrow I will drive the front end up on boards I carry, to take a bit of pressure off the front end air bag lift.

I may also rebuild the #2 solonoid in pics and diagram since I have the parts on hand. I just don't want to wake up to the "hammering" of the air relief valve purging in spurts again.

Not too happy to work by the bays as the chiggers are bad right now here in TX Hill Country. Being near ground level working in the bay is getting me bit up. More to follow when probable final solution(s) implemented.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #13 – June 10, 2018, 11:04:42 pm

Pretty sure you have figured all of this our already, but some comments...
I think the primary purpose of the 12 Vdc compressor is to maintain the seals for the slides. If I were you I would put a pressure gauge in the output line from the compressor to monitor pressure before it splits to lines 57, 75 & 76. On my system it drops to 90, compressor starts, builds to 119, and compressor shuts off. You can disconnect lines 76 & 57 and plug them. Then you will only pressurize the S/O Air Seal Tank. Don't have to worry about wet or brake tanks.
If you turn the ignition on and press the Emergency Off key on the leveling pad it will prevent the compressor from attempting to run for leveling purposes. As you mentioned, any time an air bag is raised HWH will call for the compressor to run. Leave air switch at dash off.
You can control the compressor with the inline fuse or an inline switch. You can force it to run by opening the drain valve in front of the left front tire. On ours it is the outer most valve. Once it starts, close the valve and see if operation is normal. If it does not shut off at or around 100 to 120 psi, check to make sure the Unloader solenoid is closed (if not you will hear it dumping air). If the Unloader is closed and the compressor is running I would suspect the pressure switch. Check wiring, adjust Range nut CCW to lower cut-in and cut-out pressures.
Monitor new pressure gauge to see if there are leaks in the slide tank air system. Should hold pressure for most of a day. If ok, add back line 76. That #2 solenoid did leak a little on ours. And 57.
Looking forward to your progress reports.
Dick

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #14 – June 11, 2018, 10:37:54 am

All seems correct now. Raising the coach front end by driving up on one inch thick boards (that are supporting the entire tire footprint with no overhang) has stopped the HWH system from attempting to overpressure to fill the front air bags beyond design capability. There was no excess slope light at any time, but the yellow low front end light was "just barely" out. Max lift, front air bags fully inflated.

Note: Our current site has the back end dropped all the way and the front end lifted all the way to achieve level. Everything else about the site is good so we did not want to move to another site.

From reply #12 above: "James Trianna (at FOT) later told me that if you park on a slope that exceeds the limits for the HWH, "occasionally" the system will try to level until it over-pressures, which pops the valve (forward street-side bay on my '98) making the "very" loud report. It's never happened again. " ***This appears to be a true statement. It had never happened to us before, but is exactly what was happening on our 2003.

So part one of the fix was achieved just by driving the front tires up onto one inch thick boards.

I also rebuilt the #2 solonoid attached to the aux air compressor (2003 Foretravel, not all have this solonoid). The #2 solonoid is what the air tank switch by driver position controls. It can combine the aux 12 volt compressor air tank to other air tanks, or isolate them separately.

I was getting some slow leak though at this solonoid, mainly when the HWH was over pressurizing the system in an attempt to lift front end beyond system capability. The solonoid actually looked pretty good. No debris, o-ring ok, small dimple in the plastic head portion of the "piston". I cleaned it up with rubbing alcohol, dried it, put in new o-ring, new "piston", new spring. Reassembled. Tested overnight with air tank switch off and zero leak through.

So, new $20 delivered pressure switch for compressor installed, but actually not needed (now have a good spare). During trouble shooting I had adjusted this switch downward in pressure. Now cuts off at 75 PSI, which I think is just fine for the aux compressor air tank. (note: we had never used the air tank switch to combine brake front/rear tanks in the past to the aux system, might once in a while in the future). The pressure switch has a 20 pound range, so with cut off at 75, cut in should be 55 psi.

I don't have a pressure gauge in the basement next to the aux 12 volt compressor. I may install one in the future. I was testing the air pressure settings thus far by engaging the air tank switch to combine all air tanks, and reading pressure at the dash gauges for front/rear brake air pressure.

Tested leak through by pumping down the air brake tanks with air tank switch off, read dash gauges, then reading dash gauges again 12 hours later.

No moisture or debris in the air system (ever) when draining the tanks. Previous owners (Steve and Michelle Cook) took excellent care of this coach. And I also have maintained the main air drier and the aux system desiccant.

So bottom line, the front end was lifted to extreme limits, and HWH system was erroneously over pressurizing via the aux compressor in attempt to lift front end even higher.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #15 – June 11, 2018, 11:03:25 am

Quote from: AC7880 – June 11, 2018, 10:37:54 am

All seems correct now. Raising the coach front end by driving up on one inch thick boards (that are supporting the entire tire footprint with no overhang) has stopped the HWH system from attempting to overpressure to fill the front air bags beyond design capability. There was no excess slope light at any time, but the yellow low front end light was "just barely" out. Max lift, front air bags fully inflated.

Note: Our current site has the back end dropped all the way and the front end lifted all the way to achieve level. Everything else about the site is good so we did not want to move to another site.

From reply #12 above: "James Trianna (at FOT) later told me that if you park on a slope that exceeds the limits for the HWH, "occasionally" the system will try to level until it over-pressures, which pops the valve (forward street-side bay on my '98) making the "very" loud report. It's never happened again. " ***This appears to be a true statement. It had never happened to us before, but is exactly what was happening on our 2003.

So part one of the fix was achieved just by driving the front tires up onto one inch thick boards.

I also rebuilt the #2 solonoid attached to the aux air compressor (2003 Foretravel, not all have this solonoid). The #2 solonoid is what the air tank switch by driver position controls. It can combine the aux 12 volt compressor air tank to other air tanks, or isolate them separately.

I was getting some slow leak though at this solonoid, mainly when the HWH was over pressurizing the system in an attempt to lift front end beyond system capability. The solonoid actually looked pretty good. No debris, o-ring ok, small dimple in the plastic head portion of the "piston". I cleaned it up with rubbing alcohol, dried it, put in new o-ring, new "piston", new spring. Reassembled. Tested overnight with air tank switch off and zero leak through.

So, new $20 delivered pressure switch for compressor installed, but actually not needed (now have a good spare). During trouble shooting I had adjusted this switch downward in pressure. Now cuts off at 75 PSI, which I think is just fine for the aux compressor air tank. (note: we had never used the air tank switch to combine brake front/rear tanks in the past to the aux system, might once in a while in the future). The pressure switch has a 20 pound range, so with cut off at 75, cut in should be 55 psi.

I don't have a pressure gauge in the basement next to the aux 12 volt compressor. I may install one in the future. I was testing the air pressure settings thus far by engaging the air tank switch to combine all air tanks, and reading pressure at the dash gauges for front/rear brake air pressure.

Tested leak through by pumping down the air brake tanks with air tank switch off, read dash gauges, then reading dash gauges again 12 hours later.

No moisture or debris in the air system (ever) when draining the tanks. Previous owners (Steve and Michelle Cook) took excellent care of this coach. And I also have maintained the main air drier and the aux system desiccant.

So bottom line, the front end was lifted to extreme limits, and HWH system was erroneously over pressurizing via the aux compressor in attempt to lift front end even higher.

Good troubleshooting. I saved your compressor electrical diagram, as I have never seen it before. Thanks.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #16 – June 11, 2018, 07:42:32 pm

Quote from: jcus – June 11, 2018, 11:03:25 am

Good troubleshooting. I saved your compressor electrical diagram, as I have never seen it before. Thanks.

Those diagrams were compliments of old posts by Barry Beam. That #2 solonoid hooked up to the compressor actually has a stamped number "2" on top of it.

Still no leak through from #2 solonoid late today, and still no attempt by the HWH system to over pressurize to lift the front end beyond design limits. Good reason to carry the boards I have not used with this coach (but did use on previous coach under the hydraulic jacks),

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #17 – June 11, 2018, 11:59:25 pm

Dan, of course site determines those boards but on one site we use often i found i needed to have enough boards that i do not extend one bag all the way and have another sitting with the coach on the tires.

For this i put 1x10 under each driver rear tires and on driver front three stacked boards.

Another partial help i use is to pull some gravel from under passenger rear tires. That allows less boards on driver side than otherwise.

If I simply parked with no boards or gravel removal it put hwh into an unhappy place, having to fairly frequently try to satisfy or fine tune level.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #18 – June 12, 2018, 06:31:14 am

FWIW I have never carried wood in my coach or done site landscaping. Then again, being slightly off level doesn't bother us if we can't detect it without a level. Just sayin'

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #19 – June 12, 2018, 09:05:18 am

Quote from: amos.harrison – June 12, 2018, 06:31:14 am

FWIW I have never carried wood in my coach or done site landscaping. Then again, being slightly off level doesn't bother us if we can't detect it without a level. Just sayin'

You would change your mind if your HWH system began over pressurizing beyond design limits in a failed attempt to lift air bags beyond capability, leading to loud exhausts from the pressure relief valve associated with the aux compressor system. Sounds like hammering or miniature shotgun blasts every 8 to 12 seconds, multiple times per day and night. Not fun at 3 in the morning, and neighbors wondering what is going on as that sound carries.

Now I could have shutdown the HWH system and ignored it, but I dont ignore coach problems. I explore what has caused them and how to repair or overcome them.

Also consider coach twisting with one corner too high, and one too low. Bad enough on a traditional chassis, perhaps not well advised on a FT design with rolocks etc? Front to rear off level not too bad, side to side off level not too bad, but twisting side to side is not an advisable thing. If I read Michaels post correctly, that is what he prevents by "helping" the leveling system.

Just sayin'

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #20 – June 12, 2018, 12:27:02 pm

Reminds me of my early career in the oil bidness'. Was a mud engineer on a jackup rig, my room was directly over the mud pumps. The floor was a steel deck with no insulation. Normally the sound wasn't bad and was actually somewhat soothing. Until the relief valve would go off! Sounded like a shotgun blast just a couple feet away. The first time it happened I jumped out of bed and ran outside looking for a life jacket ready to jump overboard. Never did get used to it.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #21 – June 12, 2018, 12:43:54 pm

Dan, you right. I am parked on the side of a slope. If I not add boards to compensate some for side to side and more front to back slope, just cannot level or it does barely hold and as coach settles a bit over time it loses it.

I not alone in the park needing help HWH, I think it alone only has a nine inch total correction available.

Newell next door uses about eight inches of board height under drivers front wheel

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #22 – June 12, 2018, 02:44:22 pm

Quote from: Michael & Jackie – June 12, 2018, 12:43:54 pm

Dan, you right. I am parked on the side of a slope. If I not add boards to compensate some for side to side and more front to back slope, just cannot level or it does barely hold and as coach settles a bit over time it loses it.

I not alone in the park needing help HWH, I think it alone only has a nine inch total correction available.

Newell next door uses about eight inches of board height under drivers front wheel

Sure beats twisting the frame and risking possible bulkhead separation or ro-lock issues by parking unleveled and with a twist in the chassis.

Re: Aux 12 volt compressor compartment "thumping" sound (actually air unloader)

Reply #23 – December 13, 2021, 02:21:48 am

Quote from: Tim Fiedler – June 04, 2018, 10:56:02 am

ON my 2000, the 12V air pump does not have an "unloader" it has an automatic drain that opens when the pump shuts off to drain the small plastic bowl where condensed water accumulates after operation (again, I have a 2000), and a simple pressure switch (on at 60 PSI, off at 90 PSI) is in line to trigger the pump on or off

Tim Fiedler

Sure Start Soft Start - home of SureStart soft starters TCER Direct - home of Generac Approved Aluminum and Copper TCER Composite cable generator-gas-prod - home of X-Riser Gas Risers for PE installation Call me at 630 240-9139
Gen-Pro

I think this compressor has an unloader valve. It uses the unloader air to purge water.

Tim

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