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Author Topic: Purging water system with air compressor - details?  (Read 917 times)

merlinmurph

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Purging water system with air compressor - details?
« on: October 16, 2017, 07:25:05 AM »
I'm winterizing our TT for a New England winter and have a question about something.

When using an air compressor to purge the water lines, what do you use to connect the compressor to the water input? How do you get a good enough connection without having air leaks?

I'm just curious about the details. I don't even have an air compressor, yet, but would probably get a cheap one to do this and other small tasks.

Thanks,
Dan
Dan Murphy
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2015 Ford F-250 Lariat
Hopkinton, MA

Rene T

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Re: Purging water system with air compressor - details?
« Reply #1 on: October 16, 2017, 07:37:32 AM »
I'm winterizing our TT for a New England winter and have a question about something.

When using an air compressor to purge the water lines, what do you use to connect the compressor to the water input? How do you get a good enough connection without having air leaks?

I'm just curious about the details. I don't even have an air compressor, yet, but would probably get a cheap one to do this and other small tasks.

Thanks,
Dan

This is what you'll need. You'll also need a air compressor with a little volume. I would guess at least 10 gallons. What you need to do is pressurize the system to around 40 PSI, then go around and open the faucets one at a time. Don't forget the toilet and outside shower if you have one. When the water stops flowing, go to the next faucet etc. Then finally open the low point drains one at a time just like the faucets.   You'll need to do this a couple of times at least. Between opening the faucets, you'll need to let the compressor build up pressure again.

https://www.amazon.com/Camco-36143-Brass-Quick-Connect/dp/B002XL2IEA/ref=sr_1_1?ie=UTF8&qid=1508157070&sr=8-1&keywords=rv+compressed+air+adapter
 
Rene & Lucille & co-pilot Buddy
AKA  Pep N Mem
2011 Chevy Duramax 2500 HD 4X4
2011 Montana High Country 343RL
From the Granite State of NH
& Florida Snowbird in Lakeland FL

Gary RV_Wizard

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Re: Purging water system with air compressor - details?
« Reply #2 on: October 16, 2017, 07:55:20 AM »
Most any RV parts store can supply an adapter for an air line to the water system. Even Walmart in the RV aisle.  It's usually called a "blowout plug". They are available in brass or plastic.

https://www.walmart.com/ip/Camco-Blow-Out-Plug-Quick-Connect-Brass/29764314

You don't need a large compressor, but the bigger the size (gallons), the less you have to wait for pressure to rebuild. You need a large volume of air, not high pressure, and most smaller compressors produce their max volume at rather low psi, typically 20-30 psi. I suggest using 30 psi if you have a small compressor, e.g. 2-3 gallon capacity.

Youtube has several videos on the procedure. A Google or Bing search on 'rv air winterize' will find several videos and articles online.
Gary
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NY_Dutch

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Re: Purging water system with air compressor - details?
« Reply #3 on: October 16, 2017, 08:05:29 AM »
The brass adapter that Rene and Gary linked to is exactly what I use on those rare occasions when I have to winterize. The capacity of the 2-gallon "pancake" compressor I carry onboard is a bit small for doing the job efficiently, so I 'T' it with a 7 gallon portable air tank. I pressurize both tanks to 120 PSI, but the output is regulated to 50 PSI. The output hose is connected to the brass adapter with a locking tire chuck, making it an easy one person job.
Dutch
2001 GBM Landau 34' Class A
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John From Detroit

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Re: Purging water system with air compressor - details?
« Reply #4 on: October 16, 2017, 08:11:10 AM »
There are two areas you need to concern with
The fresh water line TO the water pump.. Open the inlet strainer on the pump and empty it (lay a towel under it when you open) and after the first blow out run the pump for like 1 minute dry.  Then re-assemble the strainer.

For the rest of the house you can get an adapter at any RV store or many "Auto Departments" (Not auto parts stores but the auto dept of Wall*mart et-al).

This has a male hose thread and a, well "Tit" for want of a better name.. Some the "tit" is threaded, some it's smooth.. but that is your adapter.

Here are two of them..   I use one like the 2nd  or used that is.


https://www.amazon.com/Camco-36143-Brass-Quick-Connect/dp/B002XL2IEA

https://www.pplmotorhomes.com/parts/electrical-plumbing-lp-gas/rv-pumps-water-filters-fixtures/winterizing-by-pass-kits/rv-winterizing-blowout-plug_88-8569

I note the top plug at PPL is LISTED at 88 Dollars on sale for 3.xx... I think that LIST price is wrong. 8.8 perhaps but no way is it 88.. I got mine at Wal*mart. like that one.
« Last Edit: October 16, 2017, 08:13:54 AM by John From Detroit »
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donn

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Re: Purging water system with air compressor - details?
« Reply #5 on: October 16, 2017, 10:56:42 AM »
I have used a large and now a pancake compressor.  Both worked fine.  I have also tried pressures fronm 45 clear down to 5 PSI.  Personally I have seen no difference between compressors, with my pancake being much handier to use.  Pressure wise I find around 10 to 15 PSI works best.  Too high a pressure and you dont force the water out.  The water lines do not contain much volume so a large compressor is really a waste.  I have tried the commercially available blow out plugs and most are over priced garbage.  I made one from a short piece of old water hose amd a quick connect fitting.  Works just great.  I can blow all my lines out on about 15 minutes, and if I did not have a washer on board other than putting antifreeze in the traps I would be done.

Rene T

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Re: Purging water system with air compressor - details?
« Reply #6 on: October 16, 2017, 11:31:55 AM »
I have used a large and now a pancake compressor.  Both worked fine.  I have also tried pressures fronm 45 clear down to 5 PSI.  Personally I have seen no difference between compressors, with my pancake being much handier to use.  Pressure wise I find around 10 to 15 PSI works best.  Too high a pressure and you dont force the water out.  The water lines do not contain much volume so a large compressor is really a waste.  I have tried the commercially available blow out plugs and most are over priced garbage.  I made one from a short piece of old water hose amd a quick connect fitting.  Works just great.  I can blow all my lines out on about 15 minutes, and if I did not have a washer on board other than putting antifreeze in the traps I would be done.

I don't see where $5.85 for a brass fitting is overpriced garbage. It will last a long time.
I use to use around 40 PSI to blow out the lines. I'd run the air until there wasn't even a mist coming out of each faucets. I'd be afraid that low pressure like 5 PSI would leave water behind in low areas of the piping.
Rene & Lucille & co-pilot Buddy
AKA  Pep N Mem
2011 Chevy Duramax 2500 HD 4X4
2011 Montana High Country 343RL
From the Granite State of NH
& Florida Snowbird in Lakeland FL

merlinmurph

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Re: Purging water system with air compressor - details?
« Reply #7 on: October 16, 2017, 11:40:59 AM »
Thanks very much. I'm in Lowes now trying to put the pieces together.
I have
- a borrowed air compressor
- a plastic Camco plug from WalMart with a straight nipple on it

Just trying to get the right pieces to attach this plug to the air hose

Thanks,
Dan
Dan Murphy
2014 Keystone Laredo 294RK
2015 Ford F-250 Lariat
Hopkinton, MA

Joezeppy

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Re: Purging water system with air compressor - details?
« Reply #8 on: October 16, 2017, 11:42:22 AM »
I use one with a shut-off valve. Not the one in the link below but similar. I seem to remember it was about $15. I like the convenience of being able to shut off the air pressure without disconnecting the air hose to open my low point drains (they are capped rather than having a shut-off valve so uncapping them while pressurized results in me taking a bath!).


https://www.amazon.com/dp/B0055QAAIQ/ref=sxbs_sxwds-stvp_2?pf_rd_m=ATVPDKIKX0DER&pf_rd_p=3171424582&pd_rd_wg=jbeyp&pf_rd_r=12QYXC9S1KSG574J5FK9&pf_rd_s=desktop-sx-bottom-slot&pf_rd_t=301&pd_rd_i=B0055QAAIQ&pd_rd_w=JXiIg&pf_rd_i=rv+winterize+blow+out&pd_rd_r=79c6b5ca-b290-11e7-b1eb-dd03385067b0&ie=UTF8&qid=1508171924&sr=2
Joe & Kim
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massspike

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Re: Purging water system with air compressor - details?
« Reply #10 on: October 16, 2017, 12:07:11 PM »
Most any RV parts store can supply an adapter for an air line to the water system. Even Walmart in the RV aisle.  It's usually called a "blowout plug". They are available in brass or plastic.

https://www.walmart.com/ip/Camco-Blow-Out-Plug-Quick-Connect-Brass/29764314

OK this is weird. I live in Canada and have been searching for this exact plug but all I can find are plugs with nipples or Schraeder connectors. Walmart Canada doesn't carry the quick-connect version and neither do Canadian Tire, Loews, Home Depot, and my RV dealer. Only in Canada eh!

massspike

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Re: Purging water system with air compressor - details?
« Reply #11 on: October 16, 2017, 12:24:54 PM »
I bought a blow out plug with a Schraeder connector to use with a bicycle pump. I have a good quality "floor" pump so it gives me the option of flushing the water system where I store my trailer (no AC power for a compressor). Its a lot more labor intensive since you have to repeatedly pump up to 25psi and then go in/out of the TT to open valves but it is a $4 solution. (I normally hook my compressor up to it but it isn't as convenient as a quick-connect would be ref. my earlier post).

But I didn't have to fetch/return my TT when I forgot to blow out the black tank flush when it was in my driveway and then stored it for the winter (a senior moment) :-)

Rene T

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Re: Purging water system with air compressor - details?
« Reply #12 on: October 16, 2017, 12:50:53 PM »
This particular unit connects to a male faucet and RVs you will need a male connector to connect to the female "city" water connector.

Just pick up a double male connecter if that's the way you want to go.
Rene & Lucille & co-pilot Buddy
AKA  Pep N Mem
2011 Chevy Duramax 2500 HD 4X4
2011 Montana High Country 343RL
From the Granite State of NH
& Florida Snowbird in Lakeland FL

Joezeppy

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Re: Purging water system with air compressor - details?
« Reply #13 on: October 16, 2017, 12:51:22 PM »
This particular unit connects to a male faucet and RVs you will need a male connector to connect to the female "city" water connector.


Yah, I saw that after I posted and tested the link - oops. The one I use does have the required male end.
Joe & Kim
Upstate NY - Kuyahoora Valley
2010 GMC Sierra 2500HD - 6.0L
2017 Keystone Hideout 295BHS
Andersen Ultimate Aluminum 5th wheel hitch

Howard R

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Re: Purging water system with air compressor - details?
« Reply #14 on: October 16, 2017, 01:02:45 PM »
Don't forget the ice maker line if you have one.

Howard
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Minnesota

NY_Dutch

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Re: Purging water system with air compressor - details?
« Reply #15 on: October 16, 2017, 01:06:48 PM »
OK this is weird. I live in Canada and have been searching for this exact plug but all I can find are plugs with nipples or Schraeder connectors. Walmart Canada doesn't carry the quick-connect version and neither do Canadian Tire, Loews, Home Depot, and my RV dealer. Only in Canada eh!

I use a locking chuck on the brass Schrader valve plug from Camco.

https://www.amazon.com/Coilhose-Pneumatics-Closed-Lock-4-Inch/dp/B008PZ7LMW/
Dutch
2001 GBM Landau 34' Class A
F53 Chassis, Triton V10, TST TPMS
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox base plate

massspike

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Re: Purging water system with air compressor - details?
« Reply #16 on: October 16, 2017, 01:57:30 PM »
I use a locking chuck on the brass Schrader valve plug from Camco.

That's what I do but my compressor has the attachment with a pistol grip and gauge and that means I have to tie it down to get it to run continuously. Also I find the locking chuck for a Schrader (or Presta) valve isn't that effective and will pop off at the most inconvenient times. I like the idea of cutting out the middleman and just quick connecting the compressor to the blow out plug. OK not enough to spend $25-30 to get one shipped to Canada but next time I am in the US I'll be paying a visit to Walmart.

Gary RV_Wizard

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Re: Purging water system with air compressor - details?
« Reply #17 on: October 16, 2017, 02:55:55 PM »
Quote
I'd be afraid that low pressure like 5 PSI would leave water behind in low areas of the piping.

It's a popular misconception that more pressure moves water better. It doesn't.  You need air volume (cfm) to fill the pipes with air and push the water out of the way, but even 5 psi is sufficient as long as the lift height isn't to great. It takes 0.44 psi to raise water one foot, so 5 psi will push water to a height of about 11 ft.  Since the height between the water inlet and the highest faucet (the shower head?) is rarely even 10 ft and often only about 4 ft, 5 psi is sufficient. Use 10-20 psi if you want to play safe or move the water a bit faster, but 50 psi gains you nothing.. 

Using electricity as an analogy, you can think of cfm as amps and psi as voltage.

A tankless compressor has no reserve of air so has to produce it at a high rate to keep air flowing through the water lines. A small tankless compressor, e.g. the cheap 12v inflators you see in auto parts stores, aren't very effective because they don't push enough air even though they can reach 150-200 psi. Conversely, a 3 gallon tank unit with a max of 90 psi can usually produce about 3 cfm and that fills a water pipe easily. It takes a larger horsepower motor to provide compressed air at a high cfm.
« Last Edit: October 16, 2017, 03:01:49 PM by Gary RV_Wizard »
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NY_Dutch

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Re: Purging water system with air compressor - details?
« Reply #18 on: October 16, 2017, 08:15:11 PM »
That's what I do but my compressor has the attachment with a pistol grip and gauge and that means I have to tie it down to get it to run continuously. Also I find the locking chuck for a Schrader (or Presta) valve isn't that effective and will pop off at the most inconvenient times. I like the idea of cutting out the middleman and just quick connecting the compressor to the blow out plug. OK not enough to spend $25-30 to get one shipped to Canada but next time I am in the US I'll be paying a visit to Walmart.

I've found the type I linked to stays put pretty reliably. I also have one of the "lever lock" chucks, and it does pop off at inconvenient times, so I just keep it as a spare.
Dutch
2001 GBM Landau 34' Class A
F53 Chassis, Triton V10, TST TPMS
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox base plate

merlinmurph

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Re: Purging water system with air compressor - details?
« Reply #19 on: October 16, 2017, 08:37:01 PM »
After spending a LOT of time in Lowe's trying to put some pieces together, I finally came up with something.
Attached to the air hose is, in order of appearance:
- a shutoff valve
- a piece threading into the valve, and other end has a hose fitting
- 1/4" ID hose
- camco blowout plug

The brass piece people linked to would have been nicer and easier because it has the quick connect end.

I'll be using this in the next day or two.

Thanks again,
Dan
Dan Murphy
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2015 Ford F-250 Lariat
Hopkinton, MA

Journey

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Re: Purging water system with air compressor - details?
« Reply #20 on: October 16, 2017, 08:50:23 PM »
    The instructions on my MH states not to use over 30 psi when blowing out the lines.
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Gary RV_Wizard

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Re: Purging water system with air compressor - details?
« Reply #21 on: October 17, 2017, 09:09:05 AM »
I like these two blow-out adapters. The one with the shut-off is a bit more convenient, but both work nicely.

https://www.amazon.com/Winterize-Motorhome-Camper-Travel-Trailer/dp/B0056XBBB8/ref=sr_1_1

https://www.amazon.com/dp/B0056X3K0S?psc=1
Gary
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merlinmurph

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Re: Purging water system with air compressor - details?
« Reply #22 on: October 17, 2017, 10:33:06 AM »
I like those, too, Gary. With my current setup, I don't think I'll get much airflow because the nipple on the blowout plug is such a small diameter. The ones you link to will let the air flow.

Thanks,
Dan
Dan Murphy
2014 Keystone Laredo 294RK
2015 Ford F-250 Lariat
Hopkinton, MA

Chet18013

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Re: Purging water system with air compressor - details?
« Reply #23 on: October 18, 2017, 11:53:02 AM »
I used air to winterize our Beaver for 19 years and never had a problem. Make sure you drain the water heater and run the water pump dry. After draining the water heater, I would open all the water valves in the RV, turn the compressor, on cycle the toilet until there is only air and let the full air flow run through the entire water system for an hour. This dried the whole system out. Don't forget to pour at least 2 cups of RV anti-freeze in all the sinks and  shower drains and leave your waste and water tank drain valves open after the air purge.

I should add, you can't get to much air if all the valves are open before you start the compressor. That is unless you have a high capacity industrial one.
« Last Edit: October 18, 2017, 11:58:26 AM by Chet18013 »
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merlinmurph

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Re: Purging water system with air compressor - details?
« Reply #24 on: October 19, 2017, 08:45:03 AM »
I went to a local campground yesterday (didn't even know it was there), dumped the waste tanks and blew air thru all the water lines - sinks, shower, toilet. The water heater had already been drained and bypassed. No problems.

Then, after getting home, I realized that there is still water in the pump. Right? Every article I've read about blowing the lines out with air does not mention the water pump - and I've read a lot of them. My water pump is kind of accessible - it could be better. Can I drain it somehow, or should I put antifreeze in it?

Thanks,
Dan
Dan Murphy
2014 Keystone Laredo 294RK
2015 Ford F-250 Lariat
Hopkinton, MA

Rene T

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Re: Purging water system with air compressor - details?
« Reply #25 on: October 19, 2017, 09:00:18 AM »
My water pump is kind of accessible - it could be better. Can I drain it somehow, or should I put antifreeze in it?

Just disconnect the outlet line and run the pump for a few seconds. It won't hurt it at all.
Rene & Lucille & co-pilot Buddy
AKA  Pep N Mem
2011 Chevy Duramax 2500 HD 4X4
2011 Montana High Country 343RL
From the Granite State of NH
& Florida Snowbird in Lakeland FL

Gary RV_Wizard

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Re: Purging water system with air compressor - details?
« Reply #26 on: October 19, 2017, 09:07:45 AM »
Just run the pump dry after you empty the fresh tank.
Gary
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Summers: Black Mountain, NC
Home: Ocala National Forest, FL

merlinmurph

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Re: Purging water system with air compressor - details?
« Reply #27 on: October 19, 2017, 09:50:34 AM »
OK, thanks. I wasn't sure if running the pump with no water could damage it.

Thanks again,
Dan
Dan Murphy
2014 Keystone Laredo 294RK
2015 Ford F-250 Lariat
Hopkinton, MA

Jimdamedic

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Re: Purging water system with air compressor - details?
« Reply #28 on: October 26, 2017, 04:58:02 PM »
A question. If I blow the lines dry do I need to bypass the water heater, assuming I remove the plug and drain it?  I ask because I have to empty the storage space and remove a wall to get to the bypass. I would assume I would have to remove the plug, drain the water heater, replace the plug, blow the lines, then remove the plug again.

John From Detroit

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Re: Purging water system with air compressor - details?
« Reply #29 on: October 26, 2017, 05:25:24 PM »
No but it is easier if you still do and drain it.. You If you blow you will have to blow, drain, blow drain, Blow drain.
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