plumbing question

Pete M_2

Have an 18 port (8 hot and 10 cold) Manabloc that does not have separation between the hot and cold sides of the manifold.  When the cold supply is turned off I get hot going through both the cold and hot ports. When the hot supply is turned off I get cold going through both the hot and cold ports.

When both supplies are on it takes a few minutes for the hot side to get hot.  Longest run is about 35 feet of 1/2" pex.

Seems like they left out a divider or separation plate.

Has anyone heard of this before?  I have a call out to Viega. Was just wondering.

kcopp

sounds VERY strange....

I have installed a hundred of those manablocs and do not see how that can be.... are you sure there is not another cross connection? A moen shower valve or the like? kpc

Pete M_2

seems odd

Seems odd to me too.  I have a mixing valve on the hot supply at the WH, and thought it was clogged. So I took it off and it was clean.  I have shutoff valves on all three sides of the mixing valve, these were all shut off.  I turned on one of the hot water faucets to relieve pressure on the hot water side, and water just kept flowing, COLD water.  So then I started to wonder if I had crossed some piping or something. I checked and everything is correct hot is hot and cold is cold right into the Manabloc. Hot supply is into the top left (red side) cold supply is into the top right (blue side).  red pex to hot, blue pex to cold.  It has to be in the manifold.

EricAune

back to the manifold,

Can you feel the tubing (at the manifold) getting either hot or cold on the wrong side as you run a faucet? 



Is the house finished?  All fixtures trimmed out?  Do you have a delta shower valve (rough-in only) in the wall that does not have the cartridge in it yet? 

Do you have a circ. line?  Does it have a check valve on it?

Pete M_2

addition

It is an addition/alteration.  Some new some rehab.  Everything is still accessible.

There is no recirculation for the hot water.

The hot distribution lines are cold at first and then start to warm up in a few minutes.  The manifold is a few piping feet from the WH.

Initially I had this hooked up soley for hot and everything worked as it should.  About a month ago I finially switched the cold over, and thats when we started seeing this delay in getting hot water.  As I posted I thought it might be because the screens into the mixing valve were clogged.  I checked that recently and it was not not problem.  That is when I found that the cold was running into the hot part of the manifold.

Leo_G

switch

the manobloc if you can. sounds like a defect.



Leo G

Chris S

remodel

Is the remodel still going on?  If you have a  test nipple installed in the drop ear elbow for a shower head, and the valve is open- as for pressure testing,  what you are describing will occur.

Pete M_2

the manifold

Have a delta shower rough in valve, with stops.  The stops are closed. Checked and re-checked.  It is the manifold.

clammy

pressure diff.

i have talked to a plumber buddy and he suggested that there may be a pressure differental between your hot and cold line ,i would take a look to see if there is a restrictor in your indirects cold water inlet ,this would as far as i'm consered cause a pressure diff between your hot and cold lines ,get a good pressure gauge  and check the pressure at the fixtures it should tell you something peace and good luck clammy

Charlie from wmass

triple check

Are all the hots and colds going to the proper ports? Also are all the faucets piped with hot and cold going to the correct sides? Is the Mana bloc you have actually designed for splitting this way? You said you used it for hot only and it was fine. I am thinking something needs closed of that is not.