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moss9994 · 02-05-2018, 03:27 PM

I have a 1998 Magna 36 with the kitchen in the slide out.
We had a cold weather a couple of weeks ago. I drained the fresh water tank with the drain switch on the panel in the front everything seemed to be fine, the fresh water tank emptied.
I filled the fresh water tank with water today. The cold water side works fine no issues. For some reason there is no water going to the hot water tank. I tried it hooked to city water and with the water pump. I opened the hot water tank pressure valve thinking that would help then pulled the drain plug on the hot water heater and nothing.
I looked around trying to find something obvious but can’t figure it out.
I looked on the back side of the hot,water tank and there is no bypass valve or anything like that.
Is there some kind of switch or valve in the freshwater system that would prevent water from going to the hot water tank?

moss9994 · 02-05-2018, 05:33 PM

Figured it out. It was the check valve on the water heater.

funjnt · 02-05-2018, 06:05 PM

See, these forums help me out all the time LOL. You had a good conversation with yourself.

Anyway good to know this can happen. I wouldn't have thought there would be a check valve by the water heater but now I have to file this away so when that is the next thing that goes wrong I can check it out. Thanks.

JRadtheNoMad · 03-07-2018, 07:43 PM

Moss9994, I am experiencing a similar issue with my water heater. Can you give me some detail on what you did to solve the issue? What is required to get the check valve working?

I am starting to get cold water working some what but nothing from the hot side. I have the circuit breaker off to the water heater because I'm afraid of burning the element. Do I need to have the breaker on to fill the heating unit tank?

moss9994 · 03-08-2018, 06:11 AM

The check valve opens by water pressure, so no electricity required.
I found a random photo on the internet that helps show where they are located.
There are two. One on the line going in the water heater and one on the line going out.
They are threaded into the water heater inlet and outlet and then the plastic supply lines connect onto the check valve.

moss9994 · 03-08-2018, 06:17 AM

Photo

sanddan · 03-08-2018, 08:33 AM

What year coach?

Old-Biscuit · 03-08-2018, 08:52 AM

Quote:

Originally Posted by moss9994

The check valve opens by water pressure, so no electricity required.
I found a random photo on the internet that helps show where they are located.
There are two. One on the line going in the water heater and one on the line going out.
They are threaded into the water heater inlet and outlet and then the plastic supply lines connect onto the check valve.

Very few RV MFGs install check valve in the cold inlet side.......Winnebago and appears old Country Coach models

Hot outlet is common.....when 1 or 2 valve systems are used.

Remember.....RV MFGs are the ones that install the fittings/valves etc on the water heaters
The water heater mfgs do NOT install or ship them with check valves/fittings.

So one needs to check which valve system is being used...1, 2, 3 valves etc AND closely look at nipples on water heater tanks for 'flow direction arrows' (check valves)

The check valves are cheap plastic plunger/spring/o-ring assembly inside the nipple which can be plastic or metal housing.

JRadtheNoMad · 03-16-2018, 08:15 PM

After a slow process of replacing my cracked water pump, the broken pressure regulator, a pin hole leak in a small connector hose and replacing my water heater that had a leaking heat exchanger, whew. The water system is back, except for the hot water. Cold water is full on at all the sinks, toilet, shower and washing machine, but NO HOT! I know i'm close, and can only imagine it's a check valve, or is it? When changing the water heater, the hot and cold water connections don't have anything that appears to be a check valve. I'm not exactly sure what I'm looking for. The fresh water tank is full, tried the fresh water drain and it works as does the water pump. I have attached a picture of the rear end of the water heater and the other picture is of the water pump and regulator access area in the water bay. 2001 CC Magna, I can't wait to take a hot shower!

moss9994 · 03-17-2018, 06:04 AM

This is what it looks like. It threads onto the hot water heater and then the supply lines connect to it. Mine had two one on the line in and one on the line out of the hot water heater.
Not sure if it is what is holding up water flowing thru your hot water heater but it was on mine. Name: 6898D74D-13EA-4F82-9752-D10E2FD5FDC2.jpeg
Views: 193
Size: 33.1 KB

Name: 6898D74D-13EA-4F82-9752-D10E2FD5FDC2.jpeg
Views: 193
Size: 33.1 KB

They only let water flow one way so make sure the arrow stamped on them is pointed the right direction.

JRadtheNoMad · 03-17-2018, 09:00 AM

Quote:

Originally Posted by moss9994

This is what it looks like. It threads onto the hot water heater and then the supply lines connect to it. Mine had two one on the line in and one on the line out of the hot water heater.
Not sure if it is what is holding up water flowing thru your hot water heater but it was on mine.Attachment 195740
They only let water flow one way so make sure the arrow stamped on them is pointed the right direction.

OK, when I changed out the water heater both cold and hot brass water connections to the back of the tank were just fittings, not check valves. I am wondering if I should replace them with check valves? Would a check valve be located further down the water line, in a place I could not access? Since experiencing the no hot water issue, I have turned off the breaker to the water heater so I don't burn out the element. Would the electricity have to be on in order for the water to flow through the water heater?

Bluefoot53 · 03-17-2018, 09:17 AM

JRadtheNoMad, In the picture of the back of you hot water heater it looks like the top valve is in the off position. Don't know it is plumbed but shouldn't that valve be on?

JRadtheNoMad · 03-17-2018, 10:15 AM

Bluefoot, there are three valves and in the picture both the cold and hot hand valves are running parallel with the water line (open) the third is a winterizing valve (closed) that would "blend" both hot and cold if it were open. I wish it was that simple.

Old-Biscuit · 03-17-2018, 10:25 AM

With water supply on.........
POP open the T&P Relief Valve on water heater to check IF water is going into water heater tank

No water going in.........then issue is with COLD inlet side (sliver nipple on cold inlet---check valve??----sure could be one)

Water is going in......then issue is with HOT outlet side

Narrow down where water does/doesn't flow then you can isolate issue

3 valve system doesn't need/use check valves.
Check valves are used in lieu of having to plumb/install shutoff valve.

Once you isolate flow issue (cold in or hot out) then you need to verify no check valves used and that Cold/Hot Valves 'actually open' vs handle just move