Can't stop leak at ManaBloc

[rockintom]

Excel2014, what is the reason for having the manifold if you don't shut offs? I remember a few times we had to shut one area for one reason or another. I realize the "bad" things on these systems outweigh the "good", but don't see having the manifold without shut offs. Help me understand your comment.

[excel2014]

That could be a challenge. By putting pex shut off valves under the sinks and toilet most would be easier to shut off . But, do you want to reinvent the wheel. So, I bought a backup manibloc and hope it stays good for a few more year. Don’t like plastic.

[Jhav]

My manifold doesn't leak until I turn on my hot water heater. What is happening when my water heats up it expands and builds up pressure on the water system and manifold block will leak until I open a faucet to relieve the excess pressure. Any suggestions?

[rockintom]

John, increased pressure when the is water heated is a natural process. However to minimize this issue make sure you have the proper water heater air gap. The less air gap you have the more you notice the increase pressure. I've found over the years you need to let some off the water of the thermal pop off valve to reestablish the proper air pocket. Over time the water seems to "grow" in the air gap space.

Here's a little bit on the subject. Their focus is on that too little of air gap causes over- pressurization which in turn causes the pop off to drip.

T&P Valve
The T&P valve is a temperature and pressure valve. It is a safety device designed to release when the water temperature reaches 210 degrees or the pressure within the tank reaches 124 to 150 PSI. weeping or dripping of this valve while the water heater is heating does to mean it is defective. This is the normal expansion as the water is heated in the small closed water system of a RV. Your water heater tank is designed with an internal air gap at the top of the tank to reduce the possibility of weeping and dropping. Over time the heating water will absorbed this air. To replace this air which will correct a weeping T&P valve the steps are:
Step 1 : Turn off the water heater and let water cool.
Step 2 : Turn off the incoming water supply or water pump (first make certain the system is full, up to pressure and the water heater is full).
Step 3 : Open a faucet in the coach to release the pressure.
Step 4 : Pull the handle of the T&P valve and allow water to flow until is stops.
Step 5 : Snap the T&P valve shut, close the faucet and turn the water back on.
I might add it is not a bad idea to open the T&P valve occasionally just to make certain it has not become seized up with lime deposits. The T&P valve is a safety device but will not work correctly if seized up.

[CARLnJANIS]

Well, finally worked on the ManaBloc and got it installed a couple of weeks ago. I am not confident that the port adapters will not leak. If a port adapter has been re-tightened too many times, I will replace the seal for that port before the port cracks. To be able to replace a cone seal without removing the ManaBloc, I decided to expand the holes the PEX was passing through thereby giving me room to remove the port adapter and access the cone seal. That turned out to be a more difficult task than I had anticipated. I used a hole saw and an assortment of metal saw blades and files to cut and file away the excess metal. Took me all afternoon to expand the holes.

Now I will need to make sure I didn't cut a hole in one of the PEX lines during the drilling, cutting, and filing. That will occur when the weather is a little cooler. We aren't planning any trips for a while, so no rush.

Notice in the bottom picture, the two butter bowls to catch any leaks. Yep, still not confident about the leaks.

[rockintom]

Carl, this is a lot of work you did. I simply replaced the cone seals while I had the Mana off. I know I documented this when I was working on mine, but just as a reminder, when replacing the cone seals, my first one was a bitch. I tried to cut the old seal out with a sharp knife by slicing from the outside to the center. Not good. I was real worried that I was gonna damage the center part (IIRC copper fitting). Bottom line, I found that using a pair of needle nose pliers works best. Force the pliers into the cone seal head on. Simply unscrew the cone seal out of the plastic nut. The old seal has been crushed and spreads out and unscrews on the nut threads pretty easily. Since the new seal is smaller in diameter you can easily put the new seal in. Just snug them up to get a good crush and seal on them. With thermo cycling you'll have to come back and give them another little snug after a day or two. And as Dr. Fife says, don't let your water pressure get too high. About 50 psi is tops. Also remember to have your air space in your water heater. Over time I've found that air space gets smaller on it's own. I usually did a W/H flush quaterly, so that took care of setting the air space. I've found without proper air space, when the W/H switches on it can reach a water pressure of 100+ psi!!! Not good for weak-ass Manablock connections!

[CARLnJANIS]

Rockin',

It was your previous post about the ManaBloc that helped me with the manifold problem. A lot of good suggestions and information. I will just have to take good care of the new ManaBloc and try not to crack this one.

Thanks for your help,
Carl

[CARLnJANIS]

Well earlier this month I finished the ManaBloc replacement by testing whether or not I damage any PEX lines. I used air pressure to flushed out the old antifreeze. I then closed all the valves and connected to the city water. I opened each valve one at a time and went inside the trailer to flush the line of the valve I opened and then checked for leaks inside and out. Did this for all valves that are used. Yea, no leaks, except for the normal drip at the ManaBloc ports. Then I re-winterized the trailer.

As I was looking at the back of the wet bay, I determined that there was enough room to modify the layout of the water lines to change over to the Viega ManaBloc port connectors. However, that project will have to wait until after I have rotator cuff surgery on my right shoulder. That will most likely be after the first of 2021 with 6 - 12 months of recovery to follow. Had the left shoulder rotator cuff repaired in 2015. Most painful injury and surgery I ever endured.

Sooo, may be the Fall or Winter of 2022 before I could attempt the ManaBloc modification. Orrrr, I'll just leave it as is and let the next owner deal with it.