Plumbing problem.

[Disco-tastic]

I am currently renovating our main bathroom and we have an unusual problem...

When i run the bath in the second bathroom the water is only lukewarm, instead of its normal warm temperature. The weird thing is, when i run the basin hot tap, the water from the basin hot tap is cold, and the water in the bath becomes hot! Huh!? Both taps are on a hot water line with a tempering valve, installed straight after the hot water system.

The hot tap to the laundry is hot so its not the hot water system. The pipe after the tempering valve is hot so i dont think its the valve. My guess is its caused by an airlock in the system upstream but i am stumped as to how one hot tap can be cold and the other hot, when they run off the same single line.

At this stage all of the pipes in the bathroom have been capped, and the air in the pipes has not been purged. When we had the second bathroom installed we had the tempering valve installed on the lines that feed the shower, bath and basins. All other hot taps are connected directly to the hot water system. None of the taps on the tempering valve line are mixers, so there cannot be cross flow from a faulty mixer.

Due to the caps i have i cannot purge the lines without them leaking,and I am still a couple of weeks away from finishing the bathroom,so if i can address the problem now it will be great!

Any ideas?

Cheers

Dan

[LRJim]

I am currently renovating our main bathroom and we have an unusual problem...

When i run the bath in the second bathroom the water is only lukewarm, instead of its normal warm temperature. The weird thing is, when i run the basin hot tap, the water from the basin hot tap is cold, and the water in the bath becomes hot! Huh!? Both taps are on a hot water line with a tempering valve, installed straight after the hot water system.

The hot tap to the laundry is hot so its not the hot water system. The pipe after the tempering valve is hot so i dont think its the valve. My guess is its caused by an airlock in the system upstream but i am stumped as to how one hot tap can be cold and the other hot, when they run off the same single line.

At this stage all of the pipes in the bathroom have been capped, and the air in the pipes has not been purged. When we had the second bathroom installed we had the tempering valve installed on the lines that feed the shower, bath and basins. All other hot taps are connected directly to the hot water system. None of the taps on the tempering valve line are mixers, so there cannot be cross flow from a faulty mixer.

Due to the caps i have i cannot purge the lines without them leaking,and I am still a couple of weeks away from finishing the bathroom,so if i can address the problem now it will be great!

Any ideas?

Cheers

DanIs the bath tap a mixer or individual taps? If its a mixer the valve inside could be screwed. Just having a guess

[austastar]

Hi,
Does any water flow to any hot taps if you turn off the cold water supply line to the hws, (or an outlet from the hws).
I'm thinking along the lines of an accidental joining of two pipes or a backflow through a tap with out a jumper valve, turned on but blocked from flowing somehow.
No, I'm not a plumber.
Cheers

[350RRC]

Hi,
Does any water flow to any hot taps if you turn off the cold water supply line to the hws, (or an outlet from the hws).
I'm thinking along the lines of an accidental joining of two pipes or a backflow through a tap with out a jumper valve, turned on but blocked from flowing somehow.
No, I'm not a plumber.
Cheers

You missed your calling in life Danny Boy!

DL

[carjunkieanon]

You missed your calling in life Danny Boy!

DL

Oh Danny boy, the pipes, the pipes are calling,
From tank to tap, and to the bathroom sink,
The heat has gone, and all the water's lukewarm,
It's you, it's you, must solve it for your wife.

[1950landy]

My guess is the tempering valve needs adjusting he tempering valve should be adjustable to to adjust the temp of the hot water by mixing cold & hot water to desired temp. The one on our hot water system has a removable orange plastic removable cap , once removed there is a tringular spindle that adjusts the mix , we were supplied with a small spanner with a triangular hole to adjust the spindle. I use it to adjust the temp for summer & winter. You may have to lok up the brand you have to se how to adjust it.

[Disco-tastic]

Is the bath tap a mixer or individual taps? If its a mixer the valve inside could be screwed. Just having a guess
There's no mixers on that whole line




Hi,
Does any water flow to any hot taps if you turn off the cold water supply line to the hws, (or an outlet from the hws).
I'm thinking along the lines of an accidental joining of two pipes or a backflow through a tap with out a jumper valve, turned on but blocked from flowing somehow.
No, I'm not a plumber.
Cheers
I havent tried that but due to the tempering valve cold water would still flow out.




My guess is the tempering valve needs adjusting he tempering valve should be adjustable to to adjust the temp of the hot water by mixing cold & hot water to desired temp. The one on our hot water system has a removable orange plastic removable cap , once removed there is a tringular spindle that adjusts the mix , we were supplied with a small spanner with a triangular hole to adjust the spindle. I use it to adjust the temp for summer & winter. You may have to lok up the brand you have to se how to adjust it.
I have adjusted it and it didnt make any difference. The temp of the outlet pipe of the valve is hot, like it should be.

I should have added that all the plumbing was working great until I turned off the water to have some pipe replaced (the previous owner installed flexible braided pipe within the wall, which i wanted replaced with copper). Since then it hasnt worked properly.

The thing i cant figure out is how one tap can be cold and one hot, when they are both on the same line...

[Blknight.aus]

What style tempering valve?

Some require the same pressure on all 3 sides of the valve to function correctly

the HOT inlet side of the valve is the valve that is regulated. if the cold side has a higher pressure than the hot side then the cold water pressure will keep the hot side closed until the flow through the valve is causing the pressure to drop sufficiently for it to function again.

theres a 3 port and 4 port valve, Assuming you have a 4 port (because I cant think of how this would work on a 3 port unless you have a bridge between hot and cold with the plumbing sequence going regulator bath-Sink with the bridge exsitsing between the bath and sink

assuming its not a hot-cold link and its a 4 port regulator theres 4 ports


Cold water in
Hot water in
Regulated hot out
unregulated hot out



without knowing exactly how the plumbing is done assuming you aimed to have the sink on one port (hot unregulated) and the bath on the other (hot regulated)

If you have this valve plumbed up incorrectly its possible (and this is only theoretical you can do it deliberately but why would you?) That if you have the vavle plumbed in 180 out (inlets to outlets) and you're running the bath off of what should be the regulated hot and the tap off of the unregulated hot side the balancing is working backwards dumping cold water out the sink while trying to blend to the bath.

I dont think the newer 4 port valves should let this happen as the outlet sides should have one way valves in them.

[trout1105]

I should have added that all the plumbing was working great until I turned off the water to have some pipe replaced (the previous owner installed flexible braided pipe within the wall, which i wanted replaced with copper). Since then it hasnt worked properly.


This is the area that I would first be looking at for the problem, As you say everything worked perfectly BEFORE the braided lines were replaced.[thumbsupbig]

[1950landy]

My daughter had a problem were they ran out of hot water turned out the valve had become faulty .[bighmmm]

[Bigbjorn]

Perhaps you need a referral to a gynaecologist or a urologist. Don't they deal in plumbing problems? Probably work cheaper than licenced plumbers.[bigwhistle]

[RANDLOVER]

I agree with Trout they've messed up the connection, more specifically I think they have joined the basin hot tap into the cold line as well. This explains why the bath is lukewarm, as it is getting both tempered and cold water, then when you turn on the basin most of the cold flows out of that and so the bath becomes hot.

[Disco-tastic]

Thanks for the answers. My apologies. More clarification (from me) is needed.

All the plumber did was remove a flex hose from within the wall and replace it with hard line. It was the cold feed that fed the toilet cistern, with no other hot or cold plumbing in that area. Ie its the end of the line.

Blknight, thanks for the detailed answer its a 3 port valve connect to a tee off the main hot water line and the two taps in question are on the oulet (ie tempered). My theory at the moment is that that air in the line at the far end is causing a weird pressure issue that means the water is lukewarm. What I couldnt understand was how if I turned on two hot taps, one was cold and one was hot!

I will poke my head under the house if i get a chance and try and figure out if theres a crossover somewhere. I checked it all out once it was installed and, apart from some weird routing in and out of the subfloor, I didnt notice anything oit of place.

[Blknight.aus]

Thanks for the answers. My apologies. More clarification (from me) is needed.

All the plumber did was remove a flex hose from within the wall and replace it with hard line. It was the cold feed that fed the toilet cistern, with no other hot or cold plumbing in that area. Ie its the end of the line.

Blknight, thanks for the detailed answer its a 3 port valve connect to a tee off the main hot water line and the two taps in question are on the oulet (ie tempered). My theory at the moment is that that air in the line at the far end is causing a weird pressure issue that means the water is lukewarm. What I couldnt understand was how if I turned on two hot taps, one was cold and one was hot!

I will poke my head under the house if i get a chance and try and figure out if theres a crossover somewhere. I checked it all out once it was installed and, apart from some weird routing in and out of the subfloor, I didnt notice anything oit of place.

one going hot and the other cold can only happen if theres a cross over OR you have the 2 outlet port valve. (you dont) I'd almost be willing to bet that in the mess of routing theres been a cross join.

If you're lines havent purged the air by now who the hell plumbed them? the same guy who came up with S1 brakes or shed class clutch pipes?

[Beachy]

You need to check the tap breeches in capped area of the house have washers in them and are turned off and mixers if you have them ,water can mix when other taps are turned on and cause this

[RANDLOVER]

I agree with Beachy, you have a leaking/passing combination set i.e. the hot and cold water taps are open/leaking and you haven't realised because they are capped, as normally water would run out the spout/shower but is now unseen.

[Disco-tastic]

The only one that could do that is the shower, and i only put a cap on the shower to keep crud out during demo and tiling. The taps to that were both off, though may have been bumped since. I wouldnt think they were open enough to allow that much flow though.

I'm hoping that once everything is back together it sorts itself.

By the way, I really appreciate everyones interest and input. Thanks all

[Crustie]

If you have a cap on the outlet for the shower you must make sure you leave the mixer tap in the off position, if not you will mix the hot and cold
Sorry I haven't read all the thread but let me know if this helps
Chris

[Disco-tastic]

Well... Numpty alert.

When I installed the shower taps I thought they were hard closed. Turns out they were hard open.

You were all right. Thanks for repeating yourselves until I figured i should double check it.

:wallbash:

Dan

[Beachy]

32 years plumbing l have seen this happen many times