Water Heater bypass

bill-e · 07-18-2015, 12:17 PM

Finally getting some time with my new 26RBI. Looking at the water heater to see if it had a bypass kit installed. It has only one valve on the cold and I cant tell if there is a one way valve on the hot output.

Thoughts

Javi · 07-18-2015, 12:53 PM

Yep... that it..

If it were me I'd re-plumb it to three valves... the major benefit of three valves is no more blasts of cold water in the shower..

**hankpage** · 07-18-2015, 12:54 PM

The black valve on the cold bypasses the heater and feeds cold water to both sides of all faucets. I can not see the check valve in the hot outlet but it should be there.

bill-e · 07-18-2015, 01:54 PM

Thanks.

Doesnt really look any different than the cold side

Javi · 07-18-2015, 02:07 PM

That's it.. it's a very simple valve with a spring and silicone flapper... If you really want to be sure.. Turn off the water, drain the water heater, turn the valve... then turn the water back on.. if the tank fills back up the one-way is bad or missing..

bill-e · 07-18-2015, 02:58 PM

Thanks, and yea, I was planning on trying the bypass tomorrow before I close it up.

Tinman97423 · 02-28-2016, 08:08 AM

Quote:

Originally Posted by Javi

That's it.. it's a very simple valve with a spring and silicone flapper... If you really want to be sure.. Turn off the water, drain the water heater, turn the valve... then turn the water back on.. if the tank fills back up the one-way is bad or missing..

Javi... To stop the cold water "blast" all that is needed is to install a check valve right at the "hot" water supply line going out from the heater?
I have a 2016 Cougar 303 and it has NO check valves but does have one by pass valve like the photo above that is posted. I do not want to install any valves that requires cutting the plastic water lines. I have a small 1/2" brass flapper type check valve that will fit on to the heater outlet side and just need a short nipple to reconnect the plastic supply (hot water side).
Is my understanding of what you are saying correct?
THANK YOU......

**chuckster57** · 02-28-2016, 08:46 AM

The check valve at the hot outlet is there to prevent water from flowing backwards into the tank. Javi is describing the use of 3 distinct valves. If you look at the excellent picture he posted, it will show where they go. Cutting PEX and installing the valves is very simple and if you get these style valves ( picture for illustration only)
http://www.amazon.com/Flair--16880-P...rds=pex+valves

Using a pair of pliers will allow you to tighten them enough so they won't leak. We use them all the time at work with no failures. With the COLD IN turned ON and the HOT OUT turned ON and the BYPASS turned OFF, water will only flow from the supply to the tank cold in and come out the hot out.

Can't say I've seen an RV water heater without the check valve installed from the factory. I have replaced a few that have failed.

GaryWT · 02-28-2016, 08:50 AM

Does the cold blast happen only if you shut the water off at the showerhead? We usually don't do that as we can get two showers in back to back without shutting water off during the shower.

**chuckster57** · 02-28-2016, 08:52 AM

That seems to be the "trigger"

Tinman97423 · 02-28-2016, 08:56 AM

Chuck.... Thanks for the reply. I still want to know about the check valve. I just do not want to start cutting the PEX plastic lines if just using a check valve will work. Where I live I have no need for ever using antifreeze.
Also I'm going on a trip in a few days so just adding the check valve will be a five minute job. Will the check valve work in the hot water supply side?

**chuckster57** · 02-28-2016, 09:13 AM

Your welcome. If you look, I bet the check valve is already there.

NO the check valve by itself will not prevent the shock of cold water, the installation of the shut off valves will.

Tinman97423 · 02-28-2016, 12:43 PM

Chuck.... Just to make sure I know what your talking about before doing anything. I attached a photo of just what I have. It does look like I have some type of valve attached to the hot water outlet (small lip of brass with letters stamped that the cold water does not have). Looking at my photo can't I just install a open/close valve in the blue line connecting the hot/cold in that area that looks like a H laying on it's side?
I hate doing anything on a new unit because if there is a roof leak they will blame it on the change I made at the heater.

**chuckster57** · 02-28-2016, 03:54 PM

If your roof is leaking, "they" aren't even going to look at the water heater.

The reason for three valves is to control the flow of water. Your goal is to force ALL the incoming water to enter the heater and the ONLY water going to the faucets to be hot.

Javi · 02-29-2016, 05:32 AM

Study this, see how the hot water line is isolated from the cold water line... and how the bypass would work..

GMcKenzie · 02-29-2016, 06:28 AM

Is there any way to prevent the cold water blast without added valves? My water heater is tucked in under the stove, but further back in the corner of my trailer and I can barely get a hand in there to flip the valve I have. No way can I get in there to add valves.

Tinman97423 · 02-29-2016, 08:17 AM

[QUOTE=chuckster57;194823] If your roof is leaking, "they" aren't even going to look at the water heater.

Roof leak was meant as a sarcastic remark on how manufactures try to get out of repairing things.

**chuckster57** · 02-29-2016, 11:13 AM

[QUOTE=Tinman97423;194887]

Quote:

Originally Posted by chuckster57

If your roof is leaking, "they" aren't even going to look at the water heater.

Roof leak was meant as a sarcastic remark on how manufactures try to get out of repairing things.

I understood what you meant. As a technician I can assure you we only look at the specific issue stated by the customer, we don't "look" anywhere else. Don't get paid for it.

Tinman97423 · 06-12-2016, 09:57 AM

Cold water blast in shower..
The blast of cold water has to be stopped at the shower cold/hot valve. I am not talking about the on/off valve at shower head. Think about this! When you close the valve at the shower head the cold water has more pressure behind it that the hot water coming from the heater. That means cold water will push the hot water back into the tubing until both hot and cold pressure equalize. There is about 6 feet of tubing from the shower valve to the heater where the cold water might push back the hot only in the tubing. It might push back about 1 to 1 ½ feet. There is a check valve on the hot water side of the heater (to keep anti freeze out of the heater). YOU NEED A CHECK VALVE AS CLOSE TO THE SHOWER VALVE AS POSSIBLE ON THE HOT WATER SIDE.
I have read about this once in Trailer Life and Motor Home magazines that verified my thinking about the cold blast.
My 2016 Cougar 303SLR has a hot water line coming from the heater up to the shower and is around 6 to 7 feet long. Before starting don’t forget to DRAIN the hot water side by opening a hot water valve at the bathroom sink or shower and then the drain valve under the trailer. I removed the shower valve VERY CAREFULLY using a plastic putty knife to remove the silicone around the valve housing. AGAIN be very careful when doing this because of NO backing for the four screws that hold the valve to just 1/16 inch of fiberglass backing. You should be able to remove the hot water connection with your fingers. Do not pull it out at this time. In the compartment below remove side panels and look to the upper left of the water heater near the force air heater and you will see the Hot (red) and Cold (blue) lines coming from the shower. Follow them towards the heater and where you have room to cut the Hot side (red) leaving at least 10 inch of tubing on both ends if cutting near an existing fitting. Back in the shower pull the hot line up about a foot (DO NOT PULL IT SO FAR THAT YOU PULL THE OTHER END INTO THE WALL. YOU MIGHT NOT GET IT BACK THROUGH)
Cut the line about 6 inch from the connector and at this point install the CHECK VALVE. Push the line back into the wall and connect it back to the shower valve. Now go back down and reconnect the hot supply using a coupler. I did not need to cut out the amount from the added fittings because there was plenty of room for the extra length of the fittings.
I now have about a 1 second spot of cold before the preset temp comes back. WHAT A DIFFERENCE…..

I found all of the fittings I needed at zoro.com that claims to have more than 300,000 fittings. Everything cost about $15 including shipping.

The coupler, ½” CTS, PEX, White Product Number G4389287 Stock #16T737 PE10420.
Along with the coupler be sure to get the Coupler ½” inserts Product Number G4388255 Stock # 16T768 (Two each).

Check Valve, Polysulfone, ½ inch Product Number G2781064
Stock # 1DAT2 (No inserts needed with check valve)
PLEASE CALL THEM TO CHECK THE NUMBERS
These fittings are for PEX tubing.
PLEASE check these numbers before ordering just incase I have made a typing mistake.
This should work on any RV if you can locate the shower water lines going into the heater and there is room to cut/add coupling.

geeman · 06-14-2016, 07:33 PM

Quote:

Originally Posted by Tinman97423

Cold water blast in shower..
The blast of cold water has to be stopped at the shower cold/hot valve. I am not talking about the on/off valve at shower head. Think about this! When you close the valve at the shower head the cold water has more pressure behind it that the hot water coming from the heater. That means cold water will push the hot water back into the tubing until both hot and cold pressure equalize. There is about 6 feet of tubing from the shower valve to the heater where the cold water might push back the hot only in the tubing. It might push back about 1 to 1 ½ feet. There is a check valve on the hot water side of the heater (to keep anti freeze out of the heater). YOU NEED A CHECK VALVE AS CLOSE TO THE SHOWER VALVE AS POSSIBLE ON THE HOT WATER SIDE.
I have read about this once in Trailer Life and Motor Home magazines that verified my thinking about the cold blast.
My 2016 Cougar 303SLR has a hot water line coming from the heater up to the shower and is around 6 to 7 feet long. Before starting don’t forget to DRAIN the hot water side by opening a hot water valve at the bathroom sink or shower and then the drain valve under the trailer. I removed the shower valve VERY CAREFULLY using a plastic putty knife to remove the silicone around the valve housing. AGAIN be very careful when doing this because of NO backing for the four screws that hold the valve to just 1/16 inch of fiberglass backing. You should be able to remove the hot water connection with your fingers. Do not pull it out at this time. In the compartment below remove side panels and look to the upper left of the water heater near the force air heater and you will see the Hot (red) and Cold (blue) lines coming from the shower. Follow them towards the heater and where you have room to cut the Hot side (red) leaving at least 10 inch of tubing on both ends if cutting near an existing fitting. Back in the shower pull the hot line up about a foot (DO NOT PULL IT SO FAR THAT YOU PULL THE OTHER END INTO THE WALL. YOU MIGHT NOT GET IT BACK THROUGH)
Cut the line about 6 inch from the connector and at this point install the CHECK VALVE. Push the line back into the wall and connect it back to the shower valve. Now go back down and reconnect the hot supply using a coupler. I did not need to cut out the amount from the added fittings because there was plenty of room for the extra length of the fittings.
I now have about a 1 second spot of cold before the preset temp comes back. WHAT A DIFFERENCE…..

I found all of the fittings I needed at zoro.com that claims to have more than 300,000 fittings. Everything cost about $15 including shipping.

The coupler, ½” CTS, PEX, White Product Number G4389287 Stock #16T737 PE10420.
Along with the coupler be sure to get the Coupler ½” inserts Product Number G4388255 Stock # 16T768 (Two each).

Check Valve, Polysulfone, ½ inch Product Number G2781064
Stock # 1DAT2 (No inserts needed with check valve)
PLEASE CALL THEM TO CHECK THE NUMBERS
These fittings are for PEX tubing.
PLEASE check these numbers before ordering just incase I have made a typing mistake.
This should work on any RV if you can locate the shower water lines going into the heater and there is room to cut/add coupling.

Yes, what /\ said. The installation of valves at the hot water tank has nothing to do with "cold shocks". Great article. Saved me some typing

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