Water Heater not taking in water, no valve

1996 Fleetwood Prowler
Atwood L.P. Gas Water Heater

I hooked up the water line and I get cold water fine in the bathroom and galley. Unfortunately it seems like the water heater tank isn't taking on any water despite not having a bypass or turn off valve. The only problem I really noticed is quite a bit of calcium/lime build up but I can't imagine there is so much it is COMPLETELY stopping water flow in to and out of the tank. I also checked the relief valve and plug outside and they do not have water coming out either.

There are definitely no valves or shut offs before water is connected to the water heater itself. I checked this by off the main hook up, unhooking the water heaters cold water line and having someone turn the main water back on and it was flowing freely (i had to unhook all power to the trailer and remove the breaker panel since the water heater is placed DIRECTLY behind the break panel, ugh).

I'm really not sure what else it could be. Some sort of water shut off built into the unit? At this point i am thinking about getting the air compressor and just blowing out the plug to see if a bunch of sediment comes blowing out or knocks something loose. I'm wondering if someone has seen this type of thing before and already knows what the problem is.

You probably have a check valve in the WH output and maybe one in the cold water input.  If you had a lot of calcium buildup, you may have a blocked (clogged) check valve.  Look for a short (1 inch or so) part in-line where the lines connect to the WH.  You can remove it and connect the line direct to test if necessary.  You should be able to get replacements at Home Depot or similar retailer.

I did notice something on both of them. It looked like a kind of square connector but I can't find any check valves that look similar. I'll have to look at it again.

No water flow from the hot water tap at all?

No water flow from the pop off valve?

Water pressure on the input side of the water heater?

    Most likely a bad check valve on the input side of the water heater. 

Most hardware stores will have them.  Be careful threading it on.

Maintenance item: drain the water heater and spray it out with a sediment wand.  I do mine twice a year.

For reference here are pictures of both lines. On the input line that is the part I unscrewed and confirmed had water coming out of it but presumably its not making its way into the tank since it is not draining out of the plug outside when the plug is removed.

There doesn't appear to be a check valve between the lines and the tank hook ups as far as I can tell, nothing is similar to check valves I find on home depot or in a 'RV check valve' search.

Looks like Cheap-o plastic check valves to me, although most of the ones I've seen were black.  Well known to fail catastrophically.

Must be factory only or something because I can't find any online that look like small plastic cubes.

Disconnect both lines then remove the plastic fitting which screws into the aluminum tank fitting. Look inside both fittings. If you see internals, those are check valves. As a temporary fix, you can knock out the internals then reinstall the valves without the internals then try the water again. Also if they are check valves,  there may be an arrow on the side of the valve body indicating the flow direction. The bottom valve, (cold water inlet) the arrow should point to the tank and the upper check valve, (hot water outlet) the arrow should point away from the tank.

Here's the one from Home Depot:
http://www.homedepot.com/p/Camco-1-2-in-Brass-Back-Flow-Preventer-23303/204220179?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-VF-PLA-D26P-WaterHeaters%7c&gclid=CKWNjv7T-tMCFZeLswodgXIONg&gclsrc=aw.ds

Rene T said:

Disconnect both lines then remove the plastic fitting which screws into the aluminum tank fitting. Look inside both fittings. If you see internals, those are check valves. As a temporary fix, you can knock out the internals then reinstall the valves without the internals then try the water again. Also if they are check valves,  there may be an arrow on the side of the valve body indicating the flow direction. The bottom valve, (cold water inlet) the arrow should point to the tank and the upper check valve, (hot water outlet) the arrow should point away from the tank.

Here's the one from Home Depot:
http://www.homedepot.com/p/Camco-1-2-in-Brass-Back-Flow-Preventer-23303/204220179?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-VF-PLA-D26P-WaterHeaters%7c&gclid=CKWNjv7T-tMCFZeLswodgXIONg&gclsrc=aw.ds

Click to expand...

Well so far this worked perfectly!

I took out the check valves, popped the innards out and put them back in, WH is working like a champ now. Had some panicky moments with leaks during the process since the pipes/WH are about 5 inches away from the main breaker board, I had the trailer unhooked from a power source entirely but still. The whole experience dealing with these plastic parts has made me appreciate brass fittings a lot more.

Thanks!

Did you use Teflon tape...AND pipe dope on the male threads??? Won't leak if you did......probably leak if ya didn't!!
:-\

I used tape but no 'pipe dope', not even sure what that is.

NickSC said:

I used tape but no 'pipe dope', not even sure what that is.

Click to expand...

Pipe dope is a paste type material you put on the threads before connecting the joints. It also comes in a hard stick form. I don't know if pipe dope is necessary. If they're not leaking now, you're probably OK. When you install new check valves, you can do it then if you would feel more comfortable.

Next time, remove the drain plug, open all the faucets, open the low point drains and let the water run out until it completely stops. You shouldn't get any water when you disconnect the pipes. Make sure the water heater electricity is turned off so you don't burn up the heating element. Also make sure the tank is full and all the air is vented through all the faucets before you turn on the power.

Glad we were able to help you and thanks for getting back to us.

OP it looks like you have polybutylene waterlines. The fittings will go bad, male and female, among other things. I have replaced 4 polybutyl fittings over the last year or so. My plan is to replace all of the waterlines with Pex, which will be a job.

Search Polybutylene lawsuit and you will find lots of stuff about it.

Good luck!

NickSC said:

1996 Fleetwood Prowler
Atwood L.P. Gas Water Heater

I hooked up the water line and I get cold water fine in the bathroom and galley. Unfortunately it seems like the water heater tank isn't taking on any water despite not having a bypass or turn off valve. The only problem I really noticed is quite a bit of calcium/lime build up but I can't imagine there is so much it is COMPLETELY stopping water flow in to and out of the tank. I also checked the relief valve and plug outside and they do not have water coming out either.

There are definitely no valves or shut offs before water is connected to the water heater itself. I checked this by off the main hook up, unhooking the water heaters cold water line and having someone turn the main water back on and it was flowing freely (i had to unhook all power to the trailer and remove the breaker panel since the water heater is placed DIRECTLY behind the break panel, ugh).

I'm really not sure what else it could be. Some sort of water shut off built into the unit? At this point i am thinking about getting the air compressor and just blowing out the plug to see if a bunch of sediment comes blowing out or knocks something loose. I'm wondering if someone has seen this type of thing before and already knows what the problem is.

Click to expand...

NickSC
The water heater in my '96 Safari has a back flow preventer, (aka: check valve), in the incoming water line to the water heater tank.
When that check valve failed, (at 19 years of age), no water could enter my water heater tank.

http://www.homedepot.com/p/Camco-1-2-in-Brass-Back-Flow-Preventer-23303/204220179?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-VF-PLA-D26P-WaterHeaters%7c&gclid=CMq85ISu_NMCFQqtaQodQckI-g&gclsrc=aw.ds

BTW on some coaches that check valve is in the output water line.... and on some there are 2 check valves...
(1 in the incoming water line an another in the output water line).

mel s said:

NickSC
The water heater in my '96 Safari has a back flow preventer, (aka: check valve), in the incoming water line to the water heater tank.
When that check valve failed, (at 19 years of age), no water could enter my water heater tank.

http://www.homedepot.com/p/Camco-1-2-in-Brass-Back-Flow-Preventer-23303/204220179?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-VF-PLA-D26P-WaterHeaters%7c&gclid=CMq85ISu_NMCFQqtaQodQckI-g&gclsrc=aw.ds

BTW on some coaches that check valve is in the output water line.... and on some there are 2 check valves...
(1 in the incoming water line an another in the output water line).

Click to expand...

Mel, they fixed it yesterday. 

Rene T said:

Mel, they fixed it yesterday. 

Click to expand...

Rene T
That's good.

I was looking for some new check valves, unfortunately the ones that are in there are male on both ends which seem hard to find.

You mean like this?  I replaced two of these just recently.

http://www.ebay.com/itm/Aqua-Pro-20818-1-2-x-1-2-Lead-Free-Male-Check-Valve-1-2-Inch-x-1-2-Inch-NEW-/262888654164?hash=item3d35628554:g:4vgAAOSwTM5YwhXm

NickSC said:

I was looking for some new check valves, unfortunately the ones that are in there are male on both ends which seem hard to find.

Click to expand...

You can always purchase a close nipple and screw it into the female side of the check valve and that would give you male threads on both ends.

https://www.amazon.com/Anderson-Metals-Fitting-Nipple-Length/dp/B000BO93SU/ref=sr_1_2?ie=UTF8&qid=1495226844&sr=8-2&keywords=close+nipple

NickSC said:

I was looking for some new check valves, unfortunately the ones that are in there are male on both ends which seem hard to find.

Click to expand...

Here's another: https://www.etrailer.com/RV-Plumbing/Valterra/P23415LFVP.html