Water Pump Priming

[NMWildcat]

As detailed in previous posts, mine acts exactly as the OPs. I replaced my original pump a few years back (for other reasons) with a more expensive pump with more pressure and flow rate. Acts exactly the same when it comes to the initial priming exercise as the original pump. Just saying.

[TheWolfPaq82]

The more I read this the more I feel that this is a "Empty" WH issue and it has to fill when he does this. Time would be dependent upon how large the WH is. The pump may be primed and running, but ain't no water gonna come out till the WH is filled. Without a faucet open, there will be pressure to overcome to get the WH to eventually fill.

[NMWildcat]

Originally Posted by TheWolfPaq82

The more I read this the more I feel that this is a "Empty" WH issue and it has to fill when he does this. Time would be dependent upon how large the WH is. The pump may be primed and running, but ain't no water gonna come out till the WH is filled. Without a faucet open, there will be pressure to overcome to get the WH to eventually fill.

Agreed, that is has something to do with how much air is being pressurized, while also trying to pull water up from the tank, and simultaneously overcoming the check valve resistance.

I have tried all sorts of methods to try and figure it out, and finally gave up and just do what works. Leaving all the faucets open from the beginning seems to make no difference. I also have no WH tank (on demand). My previous RV did not have this problem, but the pump, tank, and faucets were all very close in proximity, unlike our current RV..

So, I do my initial prime like the OP. Fill the tank. Turn on the pump and let it run for 5 or 10 minutes, then briefly open a faucet to allow compressed air to escape and hopefully draw water farther into the pump input pipe from the tank. Close the faucet and let the pressure build again. Repeat until pump primes and shuts off. Then remove all air from all faucet lines. Then it's all good.

[gbaldwin]

Originally Posted by TheWolfPaq82

The more I read this the more I feel that this is a "Empty" WH issue and it has to fill when he does this. Time would be dependent upon how large the WH is. The pump may be primed and running, but ain't no water gonna come out till the WH is filled. Without a faucet open, there will be pressure to overcome to get the WH to eventually fill.

Thanks, It is very likely that this was the case this weekend.... HWT being empty. I was opening faucets... alternating various ... and also opening relief valve on HWH every now and then. intermitent sputtering of air/water/moisture from open fixtures.

I can say that for a couple of hours fiddling with it I was hearing one level of noise from the pump.... we then heard a definate change of sound from the pump and water then began flowing from the open faucet steady. We thinking it for some reason caught prime.

Thinking next trip i might fill HWT from city water hook-up at common area water source.... Then fill fresh tank.... maybe then this speeds up the process because HWT is already filled??? Sound Logical? 6 gal HWT.

[5picker]

Originally Posted by gbaldwin

Thanks, It is very likely that this was the case this weekend.... HWT being empty. I was opening faucets... alternating various ... and also opening relief valve on HWH every now and then. intermitent sputtering of air/water/moisture from open fixtures.

I can say that for a couple of hours fiddling with it I was hearing one level of noise from the pump.... we then heard a definate change of sound from the pump and water then began flowing from the open faucet steady. We thinking it for some reason caught prime.

Thinking next trip i might fill HWT from city water hook-up at common area water source.... Then fill fresh tank.... maybe then this speeds up the process because HWT is already filled??? Sound Logical? 6 gal HWT.

Or throw the water heater into bypass before trying to pressurize the rest of the plumbing.

Once the pump primes and the plumbing is pressurized, flip the bypass valve(s) and it should fill the water heater in short order.

[TheWolfPaq82]

Originally Posted by gbaldwin

Thanks, It is very likely that this was the case this weekend.... HWT being empty. I was opening faucets... alternating various ... and also opening relief valve on HWH every now and then. intermitent sputtering of air/water/moisture from open fixtures.

I can say that for a couple of hours fiddling with it I was hearing one level of noise from the pump.... we then heard a definate change of sound from the pump and water then began flowing from the open faucet steady. We thinking it for some reason caught prime.

Thinking next trip i might fill HWT from city water hook-up at common area water source.... Then fill fresh tank.... maybe then this speeds up the process because HWT is already filled??? Sound Logical? 6 gal HWT.

I did forget once to fill my WH and it took awhile to fill before I had water...not as long as yours, but I always make sure my WH is filled at home before we leave for a trip. If it sits for a couple weeks at home, I just hook up my city water, turn on one or two HOT water faucets and let it run till I figure I've run at least 6 or more gals thru the Hot water tank to make it fresh again. I only drain the tank at the end of the season when I'm ready to winterize.

[gbaldwin]

Originally Posted by TheWolfPaq82

I did forget once to fill my WH and it took awhile to fill before I had water...not as long as yours, but I always make sure my WH is filled at home before we leave for a trip. If it sits for a couple weeks at home, I just hook up my city water, turn on one or two HOT water faucets and let it run till I figure I've run at least 6 or more gals thru the Hot water tank to make it fresh again. I only drain the tank at the end of the season when I'm ready to winterize.

Q:

Does the HWT drain when you open your low point HW side drain?

[5picker]

Originally Posted by gbaldwin

Q:

Does the HWT drain when you open your low point HW side drain?

It does. (mostly if you open a faucet to let air in)

BUT... it is NOT recommended to drain this way as it will also draw gunk from the water heater into the plumbing (not all of the gunk drains out) where some of that gunk then finds its way to things like the faucet aerators and the toilet valve.

Always drain the water heater by removing the plug/anode.

[Mr. Dan]

Originally Posted by 5picker

It does. (mostly if you open a faucet to let air in)

BUT... it is NOT recommended to drain this way as it will also draw gunk from the water heater into the plumbing (not all of the gunk drains out) where some of that gunk then finds its way to things like the faucet aerators and the toilet valve.

Always drain the water heater by removing the plug/anode.

X2. I have never/will never drain my water heater through the low point drain.

[JPin AZ]

FWIW My new to me 2011 ROO had the same problem. The first time I tried to run the pump it would not prime. I ran it for a long time and nothing. I had just read the post about city water filling the holding tank so I connected the city water and ran the pump. It primed almost immediately. I have not had it on city water since, after reading this post I will do that well before my next trip. It could not hurt to connect it to the city water and purge the system every time.

[gbaldwin]

Originally Posted by JPin AZ

FWIW My new to me 2011 ROO had the same problem. The first time I tried to run the pump it would not prime. I ran it for a long time and nothing. I had just read the post about city water filling the holding tank so I connected the city water and ran the pump. It primed almost immediately. I have not had it on city water since, after reading this post I will do that well before my next trip. It could not hurt to connect it to the city water and purge the system every time.

Thanks for input. It is funny that some indicate that filling the city water side (Hot water tank included) and purging will help before filling the fresh water tank; others experience is that it does not help because there is a check valve on the city water side that prevents water from getting to pump.... which is priming with water from the tank side. But these ideas are all great and certainly give me things to try next time out. Just have to figure out what seems to work best.

[Scrapper]

Originally Posted by gbaldwin

Thanks for input. It is funny that some indicate that filling the city water side (Hot water tank included) and purging will help before filling the fresh water tank; others experience is that it does not help because there is a check valve on the city water side that prevents water from getting to pump.... which is priming with water from the tank side. But these ideas are all great and certainly give me things to try next time out. Just have to figure out what seems to work best.

Actually it makes sense if you think about it, as the water pump does not have to fill the water heater and the rest of the plumbing. The check valve at the water pump is to prevent the filling of your fresh water tank by the city water. When your check valve does not seat properly, as it happens for some, the fw tank will fill until it overflows.

[onetonford]

Most of these pumps depending on cost are between 1 to 3.5 GPM so if the lift from the tank is higher could take along time to fill a 6 to 10gal water heater and if you add piping and water filter could take some time to bleed all the air off. On my Wildcat the tank is at the back of the trailer and the pump is in the basement mounted to the ceiling so when the system is full of air can take along time to prime since it is almost twenty feet on the suction line alone to the pump. On my old fiver the pump was right next to the tank and it was up and running in just a few minutes.

[quick83]

You will eventually need to clean the screen in it. Maybe it’s got something in it now. May cause it to take awhile to prime. Just a thought.

[gkehman]

My water pump has lost its prime on several occasions and I found the outside shower seems to help it prime faster, if I open and close that faucet. On my 2304KS the outside shower is the lowest faucet in the system.