DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Plumbing (
-   -   A blocked water line causing water to loose heat? (

Snav 05-07-2010 09:46 AM

A blocked water line causing water to loose heat?
*edit - this problem has been resolved, thanks for reading and responding*

I'll try to write this so it makes sense and doesn't confuse anyone - I need feedback before I start to fix the problem. sorry -I noticed I typed 'loose' instead of 'lose'

At the left side of the house is the laundry and kitchen, hot water heater.
Center is the master bathroom (the bathroom that I'm working on)
Right is the main bathroom (bathroom that I redid a few years ago).

The hot water line comes from the hot water heater - has 2 90 degree turns - and continues past the master bath and to the main bath like this:

Hot water heater ________ master bathroom ________ main bathroom

The other day I connect the master bath tub faucet into the hot water line. Connecting went mostly ok - no leaks (no leaks anywhere on the line, for that matter). When I installed the Tee onto the hot water line - which branches off to the new tub faucet - some water dribbled into the Tee from the right side. So I removed the Tee, wiped off the cement, let it dry, and re-cemented.
(I also connected the cold water line to the tub faucet - no problems happened).

However, since connecting the new line into the hot water supply line the hot water in the main bathroom (on the right side of the house) has only reached 90 degrees (I've checked it with a thermometer - at the sink and at the tub/shower)

COLD water flows fine and is quite cold in the main bathroom.
Hot water, however, just isn't as hot. . . it *seems* to have the same amount of water pressure, but it is just warm, not hot.
Hot water flows just fine through the kitchen sink and into the dishwasher and washing machine, too.

Now - I checked my lines SEVERAL times to ensure I didn't cross the lines over - hot is all hot, cold is all cold. There are NO leaks, I'm quite sure of this. I have checked the lines with the hot water running - being turned off and on, etc etc.

What I did notice, though, is that at the Tee where the new hot water line branches off and goes to the master-tub one side (the left side) of the Tee is hot to the touch (acceptable pipe hot - not too hot) and the other side of the Tee is much cooler (barely warm) to the touch - just 2 inches apart.

So - that leads me to question if the wet-cement inside the Tee expanded or somehow clogged the Tee and is slowing the flow of water. By the time the water runs through the blockage and up to the line it's lost 35 degrees (we have our water set at a temperature of 125).

This, to me, doesn't *quite* make sense. Wouldn't a blockage SLOW down the flow of water? (it's hard to tell - our faucet aerates the water, anyway, reduced pressure isn't obvious).

I've let the hot water run for 30 minutes - maybe thinking that it would eventually get 'hot' at that end - but that doesn't happen. It reaches 90 degrees and stays there.

So - if it's not a blockage of some type is it the distributor bar for the tub-faucet? Could it somehow be feeding cold water into the hot water line when the hot water is turned on?

But - that doesn't make any sense, either. I don't see HOW a faucet bar can fail like that and permit cold water to enter into a pressurized hot water line.

My plan is simple - replace the tee, be certain to dry the pipe well and not to over apply the cement - and see if it fixes the problem.

but if it doesn't? I guess I can cap off the lines to the tub and replace the distributor bar to see if it's defaulted somehow.

Yoyizit 05-07-2010 12:19 PM

This table
seems to be saying you'll lose ~4.5F per minute for a 125F water temp and an 85F ambient for a 1/2" ID copper pipe.
The temperature will drop more slowly as it approaches ambient.

I don't have a feeling for this, but you can test it easily enough.

AllanJ 05-07-2010 12:35 PM

Was a faucet not properly shut off or the master bathtub turned off at the sprayer hose instead of using the faucets? This can cause cold water to cross over at distributor bar of say the Master bathtub with the spout or sprayer hose closed off and go up the hot pipe the wrong way and over to the main bathroom when that tub or sink was being used.

Do you have an anti-scald valve in the main bathtub faucet that could be severely limiting the hot water proportions?

Snav 05-07-2010 01:23 PM

whenever I shut off the water I turn on the kitchen faucet and the outside hose (in front of the house) and turn the water off (we have one control at the meter - it's 50' away from the house, towards the street.) I leave these faucets on until I check my water-work for leaks.

I have the pipes in place for the new tub faucet. The tub spout is capped off - the shower spout is capped off.
I do not have handles on it.
*so* I honestly don't know if the new tub faucet is on or off. I believe it's off, but I can't tell. If it isn't off - and the caps are preventing the water from leaving the faucet through traditional means - perhaps it is somehow forcing it back into the line. (This kind of makes sense the ore I think about it)

so - before I cut into the line (even though it wouldn't be a big deal and take me just 10 minutes to replace the tee first) maybe I should turn off the water, slide the tub back into place and connect the drain, install the faucet spout and turn the water back on - determine if it functions right and which way is on and off. . . and then reassess?

Now that I think about it - it seems more likely that this is in fact the case and that the tee isn't blocked - the precise temperature and seemingly unaffected water pressure is pushing me to rule that out.

SuperPlumberGuy 05-07-2010 01:32 PM

AllanJ has it right, something is open in the master allowing cold water to cross over to the hot side. Is the tub or shower valve open but capped? Is it a Delta valve that does not have the cartridge installed yet? The symptoms you describe are almost certainly being caused by a cross connection. :yes:

Snav 05-07-2010 01:54 PM

It's a Moen faucet/shower combo - cartridgeless but I don't think that would be a determining factor.

I'll work in it and hopefully have it figured out soon - thanks for the replies.

Snav 05-07-2010 02:18 PM

Yeah - that was it! The distributor on the new faucet was on 'tub spout' and the cold water faucet was on 1/4 turn - but the shower and tub faucets were capped forcing the water back into the pipe.
I removed the lines from the distributor bar, capped them off, and water temperature was fully restored.

However, since hot and cold aren't being fed into the pipe together, I can now also see that the Tee is partially slowing the water flow - so both things are a factor, I still need to replace the Tee in the pipe.


All times are GMT -5. The time now is 01:20 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1