Can't pump all water out of tank?

[NRVhawk]

It seems that the water tank in my 2016 Hawk has at least two gallons of water at the bottom that the pump can't reach. Is that normal?

Now that night temperatures have reached freezing where I live, I decided to add a couple of gallons of potable antifreeze to the tank in case there's any water in the bottom.

After I added the two gallons of antifreeze, I turned on the pump and opened the faucet to pull antifreeze through the plumbing. The pump labored and drew a mixture of air and water. That seems to indicate that the pump inlet is just about at the height of the top of the 2 gallons in the tank. Right?

There might have been even more water in the tank before I added the antifreeze. Last weekend, I filled the tank until water ran out of the vent, and then I drained the water through the valve on the bank of the truck. Catching the water in 5 gallon buckets, I was able to measure 18 gallons before the water stopped draining (with the truck on a 10 degree incline to help the draining). If the tank capacity is 20 gallons, then there may have been two gallons already in the tank before adding the antifreeze.

 

[longhorn1]

The only place that should be holding any water if you have used the lever to drain water from the water heater back into the tank is the water heater tank. It is metal and if you run 2-3 gallons of RV antifreeze thru the faucets, including the outdoor shower you shouldn't have any issues. The drain line is in the bottom of the tank so there shouldn't be any water left after you open the spigot on the back of the camper. There shouldn't be any water in the water tank if you park on a slope and drain it. When you reverse the flow from the water heater back to the tank drive around and you will get 98%+/- out of the water heater.

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[Wallowa]

The only place that should be holding any water if you have used the lever to drain water from the water heater back into the tank is the water heater tank. It is metal and if you run 2-3 gallons of RV antifreeze thru the faucets, including the outdoor shower you shouldn't have any issues. The drain line is in the bottom of the tank so there shouldn't be any water left after you open the spigot on the back of the camper. There shouldn't be any water in the water tank if you park on a slope and drain it. When you reverse the flow from the water heater back to the tank drive around and you will get 98%+/- out of the water heater.

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Would love a verification of how much can't be drained out of the 6 gal hot water heater...I believe it is at least a gallon that will not drain back into main water tank...and then out the back drain, even on a hill..

Of course very interested in the assumption that you can never "reach" the last two gallons in the main water tank by pumping it out...

I guess bottom line for me is knowing how much water may be in our '16 Hawk even after draining hot water heater into main tank and then draining all the storage and plumbing out the back...

Thanks folks..

Phil

 

[longhorn1]

The manufacturer of the hot water heater states that any water left will not damage the water heater if it freezes. So with that said putting 2-3 gallons of RV anti-freeze into the tank and turning on both hot and cold water faucets. I see pink almost immediately and that means it is going through the hot water heater.

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[longhorn1]

Atwood states that up to 2qts will remain in the hot water tank and that will not damage the hot water heater if it freezes

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[rando]

There will always be a little bit of water left in the main tank, particularly if you drain it using the pump and even if you drain it with the drain line. At least on my camper, the fittings are in the end of the tank, not the bottom, and the lines screw into fittings that are 'plastic welded' into the tank. This leaves the bottom edge of the drain fitting ~ 1" above the bottom of the tank, leaving about a gallon in the bottom of the tank. The pump loses suction when the top edge of the fitting comes out of the water, so the using the pump you leave ~ 2 gallons in the tank. I don't think this is an issue for winter as there is plenty of space for the water to expand into when it freezes.

 

[Wallowa]

Still totally unqualified, but... The "logic" behind adding RV anti-freeze to a camper water system is the "assumption" not all water can be removed. Considering how difficult repairs are in such a small camper space, caution would dictate using RV anti-freeze, circulating/flushing the anti-freeze in every wet place, and then draining as much as possible/reasonable. Posting have occasionally reported freeze damage in some unforeseen nook...

Hiker,

Great point; we are assuming a lot...how many have actually had damage in a FWC plumbing or appliances? You know the skeptic in me says that we just are chasing a potential issue without real hard information about actual damage one of us on the forum can directly tie to water freezing in the system...

We always play the probablities, and certainly getting to a busted line or valve would be a nightmare, but like so much in life it is best to know the actual risk before making judgements on how or if it can be mitigated or eliminated.


Phil

 

[NRVhawk]

... the lines screw into fittings that are 'plastic welded' into the tank. This leaves the bottom edge of the drain fitting ~ 1" above the bottom of the tank, leaving about a gallon in the bottom of the tank. The pump loses suction when the top edge of the fitting comes out of the water, so the using the pump you leave ~ 2 gallons in the tank....

Thanks for the description. This helps me visualize what's going on without tearing into the cabinets. What I observed pretty much makes sense in light of this description.

I should have pointed out that my camper doesn't have the hot water heater, so I'm only dealing with the main water tank.

 

[longhorn1]

Anti-freeze and you should be safe

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[northshorehenry]

You know what sucks about RV anti-freeze? I put it in last winter and it took me the entire summer of camping (filling the water tank, using it, draining it, repeat each camping trip) to get rid of the taste of the anti-freeze in the water. Now it's winter again and I have to do it again. Gawd damn it!

 

[longhorn1]

Northshore, You might consider flushing the tank, filling with water and 1/4 cup of bleach. Give it an hour, drain and fill with water and you should be good. We never tasted any after effects of the RV anti-freeze (pink). jd

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[cdbrow1]

I have a 2015 hawk. After the tank drains I find that I need to keep opening the drain valve every few days until no more water comes out. Movement helps get the last bit of water out of the system.

I don't worry about freeze damage since freezing water in a nearly empty tank has plenty of room to expand. The lines are dry.

I have thought about using a blow down fitting

http://www.etrailer.com/RV-Plumbing/Camco/CAM36143.html?feed=npn&gclid=CjwKEAiA6YDBBRDwtpTQnYzx5lASJAC57ObMxBmMajRFJC0os0dL2NvFYC6hzaqGDvwj1jvt645b7RoCk7jw_wcB

But not sure about other effects to the system.

 

[Ronanmd1]

A couple years ago, I simply drained the system as best as I could without using antifreeze. When I went to use the camper in the spring my pump didn't work anymore (would run but never pump water). I presumed that it had been damaged by water freezing within it. Easy to replace, but it made me a bit more paranoid about possible other damage to lines etc. I also tried blowing out the remaining water using the compressor, but that didn't seem to push out any more water from the faucets, shower or drain than what had already drained out using the pump and gravity.

This year, I decided to keep the camper on for a few extra weeks of shoulder camping and to give me enough time to build up my indoor shower. I decided to go with the antifreeze and made sure to run it through the pump to be safe.

 

[cdbrow1]

A couple years ago, I simply drained the system as best as I could without using antifreeze. When I went to use the camper in the spring my pump didn't work anymore (would run but never pump water). I presumed that it had been damaged by water freezing within it. Easy to replace, but it made me a bit more paranoid about possible other damage to lines etc. I also tried blowing out the remaining water using the compressor, but that didn't seem to push out any more water from the faucets, shower or drain than what had already drained out using the pump and gravity.

This year, I decided to keep the camper on for a few extra weeks of shoulder camping and to give me enough time to build up my indoor shower. I decided to go with the antifreeze and made sure to run it through the pump to be safe.

When it comes to freezing pipes always listen to the Candians....

 

[Wallowa]

A couple years ago, I simply drained the system as best as I could without using antifreeze. When I went to use the camper in the spring my pump didn't work anymore (would run but never pump water). I presumed that it had been damaged by water freezing within it. Easy to replace, but it made me a bit more paranoid about possible other damage to lines etc. I also tried blowing out the remaining water using the compressor, but that didn't seem to push out any more water from the faucets, shower or drain than what had already drained out using the pump and gravity.

This year, I decided to keep the camper on for a few extra weeks of shoulder camping and to give me enough time to build up my indoor shower. I decided to go with the antifreeze and made sure to run it through the pump to be safe.

Ron,

I assume you replaced the pump. Did you test or dismantle the defective pump to verify why it died?

Thanks,

Phil

 

[rando]

Draining the pump has been one of my concerns as well, which was the motivation behind this thread:
http://www.wanderthewest.com/forum/topic/13304-quick-winterizing-de-winterizing-tips/

What I have done since then is to pull the inlet strainer (which was full of water, even after running the pump 'dry') and run the pump some more. This seemed to get a little more water out of the pump - hopefully enough that it can survive a freeze.

 

[northshorehenry]

Northshore, You might consider flushing the tank, filling with water and 1/4 cup of bleach. Give it an hour, drain and fill with water and you should be good. We never tasted any after effects of the RV anti-freeze (pink). jd

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Longhorn,
I flushed the entire system in my driveway three times. Then over the course of the year, filled and drained the tank through normal usage, emptying the tank on each return trip, probably six times. The anti-freeze taste finally was gone by September. I am not sure how many more times I need to flus this thing. :-(

 

[Ronanmd1]

Ron,

I assume you replaced the pump. Did you test or dismantle the defective pump to verify why it died?

Thanks,

Phil

Phil - Yep, simply replaced the pump. Took about 15 minutes. Never had time dismantle the pump to be sure. But, I never had the same issue after running antifreeze through the pump. Still, I can't be absolutely sure that freezing caused the problem...

Jason

 

[stanbiker]

I added the Camco kit with a valve at the pump inlet to push the RV antifreeze through the system. I never add any antifreeze to the hot water tank or fresh water tank.

https://www.amazon.com/Camco-36543-Pump-Converter-Winterizing/dp/B0006JJ588/ref=sr_1_1?s=automotive&ie=UTF8&qid=1478892412&sr=1-1&keywords=rv+winterizing+kit

 

[NRVhawk]

I added the Camco kit with a valve at the pump inlet to push the RV antifreeze through the system. I never add any antifreeze to the hot water tank or fresh water tank.

https://www.amazon.com/Camco-36543-Pump-Converter-Winterizing/dp/B0006JJ588/ref=sr_1_1?s=automotive&ie=UTF8&qid=1478892412&sr=1-1&keywords=rv+winterizing+kit

Sounds like a good way to avoid having to flush antifreeze out of the fresh water tank every spring. I noticed that some of the reviews faulted the valve for restricting flow - did you experience any problems with that?