no hot water pressure

[paddler67]

Help
No water coming out on the hot water side but have normal pressure on the cold water side. Open the relief valve and did have a water flow but didn't have a lot of pressure. Any suggestions.

[bncinwv]

My first thought (depending on model and year which you did not provide) is to engage the hot water bypass valve and see if the pressure returns. If it does, then you will know the problem is in the hot water tank itself. If it does not, then the problem would probably be an obstruction in the hot water lines themselves. Not much help here as I have never had the problem.
Bingo

[Carl n Susan]

Most likely you have a failed hot water check valve. This puppy sits on the output port of the water heater. When it fails, no water gets through.

Here is a link to a previous discussion on this topic. It includes a link to Oz's pictures of the replacement task.
http://www.montanaowners.com/forums/...ad.php?t=54909

Do a Search and you will find many posts on this problem.

[dieselguy]

I'm with Carl ... check valve probably at fault.

[jcurtis934]

Have replace two of these so far on two other rvs here in the park, a fifth wheel and a motorhome. The failure mode is usually a reduced flow, sometimes no flow. When you take it off, you will see why the water flow was so crappy. By the way, it will be the connection to the top-most part of the water heater on the backside. The bottom connection is the cold water feed and it doesn't have a check valve even though it may look like one at first glance. John

[WeBeFulltime]

Yep, got to be the check valve.

[paddler67]

I removed the pipe fitting from the top of the water heater and remove a small cone shape piece of plastic and connected the pipe back and have good water flow. I didn't know anything about a back flow valve.
Do I need to put a valve back? The water is flowing so good I don't want to remove the line.
What happens if I don't install that little plastic cone shape piece?
We have a 07 montana md.3295rk.

[awaywego]

The back flow keeps antifreeze from going into the water heater if you winterize. You can buy a brass replacement for it at some dealers.

[Overlord]

quote:Originally posted by awaywego

The back flow keeps antifreeze from going into the water heater if you winterize. You can buy a brass replacement for it at some dealers.

Ummm, ...the HWH by-pass valve in the convenience center is what keeps RV antifreeze out of the water heater. On Edit: Well, poop! I hate it when I'm wrong! (remove foot from mouth ) The check valve is also part of the HWH by-pass equation that keeps anti-freeze out too. Didn't think of it as such, as my old rig had three manual valves to do the deed instead of just one like we have now. Sorry, awaywego.

The check valve on the outlet of the water heater helps keep hot water (edit: ....and anti-freeze while in by-pass configuration ) from backing up into the tank. Without one, turning on the cold at a faucet or flushing the toilet causes a temporary pressure drop and draws hot water backwards out of the tank until the line pressures are equalized, if there is a tee to another faucet in the cold supply line very close to the water heater inlet, it can even output hot water through the cold side of that faucet.

In fact, some put the check valve on the cold inlet to the HWH oriented so the check valve only allows cold water into the HWH, instead of at the hot outlet oriented so that it only allows hot water out of the tank. Either option makes for a one-way flow from the HWH.

[Neil.M]

My issue was the check valve. You can remove it and rehook up the line with out it to give you hot water until you replace it. Ozz has them on his site http://ozzrvparts.com/MOCMembers.html

[Phil P]

Hi

As long as we are talking about the hot water heater check valve here is a thought.

Ours was making noise so when I last got energetic and started doing modifications to the trailer I removed ours and went to a plumbing supply company and they brought one to me in the OEM box. I opened the box to match it to the one I removed and it was the same brand. The only difference was a piece of paper in the box that said in big black letters “not for use in the hot water line”.

So I ordered one from OZ. A note here ordering from OZ is much better than trying to do business with one of the RV Company’s. He and his wife went out of their way to get the valve to me in a timely manner.

Now for the shocker, the valve OZ sent me was the same brand and construction as the one I removed and the one I looked at from the pluming supply house the only difference was the absence of the piece of paper.

The valve is installed and working well and doesn’t make noise.

Phil P

[paddler67]

.thanks a bunch for the help. with the little plastic piece removed I do have a lot of water pressure.