Hot / cold water mystery ? ( long winded )

[flat350]

I've been in the trade for 20 years and have not experienced this before . We have a 5 1/2 bath house (3 on 3rd fl. , 1 1/2 on 1st fl. , 1 in base ) , 2 -50 gallon heaters in series , recirc lines to all baths and kitchen , 2 - circ pumps one at each heater , all baths have an isolation valve on the line serving it . The house was to only have one pump originally taking care of all the baths , as an after thought the homeowner requested the second pump be added to serve only the kitchen . The layout of the cold water pipe in the house is from the meter first take off is riser to 1/2 bath and a full on the 2nd , 2nd take off is a full on the 2nd ,3rd take off is a full on the 2nd ,4th take off is base bath , 5th take off is kit , 6th take off is a full on the 1st and a laundry on the 2nd , water heaters are at the end of the run and the hot follows the cold back in reverse order of course .

Everything worked fine in the house for about 4 months and then we got a complaint about no cold water at the kit. What we found was that the hot water was backing up in the cold line when it sat stagnant over night . we have gone thru everything that we can think of ( every body said that there has to be a return line crossed ) WE have checked every thing ,piped the heaters in parralell ( no change ), Checked for crossed water lines ( 100% positive none are crossed ) put both pumps on the first heater ( no change), put both pumps on the 2nd heater ( no change ) ,added a Watts dual check to the cold line in Oct of 07 ,this stopped the hot water from backing up into the cold and everything seemed to be OK , until Mar. of 08 . What ARE WE MISSING HERE !

Steve

[NHMaster3015]

:thisthreadisworthle:thisthreadisworthle

[HVAC HAWK]

a bad kitchen faucet letting the water mix ??:idea:

[TOPDAWG]

Would you happen to have any Y hoses connected in a garage or laundry? you can try using swing checks in line to see if that helps. Check your water pressure and see if your expansion tanks are not full of water.

[flat350]

Pictures wont be possible with a finished basement , you should be able to picture a basic water heater install in your mind . Water is not mixing at a fct. we turned off the angle stops at each fixture to be sure that wasn't happening.

[flat350]

No expansion tanks required by the village and I would think the Watts dual check that we installed would be better than a swing check at stopping flow . .

[TOPDAWG]

I have no idea what it might be then other than thermal expansion, Maybe dual checks are weak and water may be going back through a ballcock

[westcoastplumber]

I have no idea what it might be then other than thermal expansion, Maybe dual checks are weak and water may be going back through a ballcock

this is what I was thinking

bleed over somewhere.....through a shower valve or some single handle fixture, gotta do a test.

I have hot water turn up in downstairs toilets before because of bad cartridges.:eek:

[flat350]

Is it possible that the 2 pumps are creating enough of a pressure differential that they can overcome street pressure and cause the hot water to back up when no water is in use ?

[TOPDAWG]

this is what I was thinking

bleed over somewhere.....through a shower valve or some single handle fixture, gotta do a test.

I have hot water turn up in downstairs toilets before because of bad cartridges.:eek:
that very well could be, he threw me for a loop when he said he put in the dual check and it stopped the problem for a few months then it reappeared:confused:

[flat350]

Thats right , we put in a Watts dual check a #7 and it stopped the problem for 5 months and then it reappeared , thats what makes it really weird .

[TOPDAWG]

Is it possible that the 2 pumps are creating enough of a pressure differential that they can overcome street pressure and cause the hot water to back up when no water is in use ?
if you have the checks and circulators in the right position you should only be pushing the water through the loop with no pressure build up what so ever.

[flat350]

I also did this exact same house a few months later on another job and its piped exactly the same and the 2nd house works fine with no problems , the only thing different between them is one has Kohler fcts. and the other one has Danze fcts. The problem house has the Danze fcts.

[MPMGinAL]

Is it hot water or just not cold water i.e. luke warm?

[flat350]

The kit. fct will have hot water on both sides , maybe a little cooler on the cold side . A little more info , the kit fct. is a Grohe and all the lav fcts. are 2 handle widespread Danze , the tub or shower fcts. are Danze thermostatic not pressure balanced valves .

[MPMGinAL]

Are there screwdriver stops on shower valves? Can you eliminate them from the equation? Hot water dispenser? Any type of thermal expansion device? Maybe Mr. Innocent HO called a plumber in that installed a watts governor 80 TX ballcock? How did you determine that it was not the kitchen faucet? Did you make sure that the dishwasher was not connected to cold water? Don't mean to insult you im just reaching here. and typing everthing that comes to mind

[MPMGinAL]

If everything else is in check and the dual-check worked before i would say add a thermal exspansion tank to both heaters and replace check valve. swing valve is not a bad idea. They are a little less mechanical, not as likely to fail, but not as good as check valve working properly. This would make sense since the only changing factor really is the city water pressures?

[flat350]

As of now we have the house to where we can shut off any one fct. or the entire bath at the riser to it . As for the kit. fct. its easy to turn off the stops in the cabinet to eliminate it from the equation and both D/W are piped with hot water and are valved to be able to isolate them . Before I had said that we can shut down every line and fct. and isolate them from the main in the basement

[JCsPlumbing]

Now this is a plumbing diagnosis quiz! :) What type of circulating pumps/system do you have in?

[MPMGinAL]

I'm picturing a typical distribution piping system. Its not a manifold system is it?

[flat350]

Feel free to type away you wont insult me , I can't believe no one else has had this happen to them . there has to be something simple that I'm overlooking along with my service guy who cant foigure it out either .

[JCsPlumbing]

What kind of pump/system do you have on the kitchen?

[JCsPlumbing]

Is it a retrofit with a bypass valve?

[flat350]

I cant remember the pump brand there small like 1/20 hp I think.It's what I call a basic basement house with a horizontal main running the length of the house and branches to risers feeding the 2nd floor baths . We have beat our selfs up trying to figure this out and still dont have the answer , it's not a retro fit this is a new home.

[JCsPlumbing]

Waiting...:rolleyes:

[JCsPlumbing]

The reason I'm asking is you stated that it was added later. Sometimes the only way to add one later, or the cheapest way, is one that has a bypass valve under the farthest fixture that allows hot water to go into the cold line. I could be way off. That's just a guess.

[Rambo]

You might try a thermal relief valve such as THIS (http://www.watts.com/pro/_productsFull_tree.asp?catId=64&parCat=327&pid=564&ref=2)

[MPMGinAL]

I hate to beat a dead dog, but i am leaning toward thermal exspansion. I one had a nursing home that had no hot water to one wing and cound out that the culprit was an old wall mounted faucet that wasn't even used. Never leaked or anything just letter water cycle through it. Not really the same as your problem. Another time one of y techs changed out a heater that was piped in series with another and put the TXT on the cold inlet of the wecond heater causing this. We moved the heater to the right location (actual cold inlet of first tank) and problem fixed.

[flat350]

I remember the pumps , They both are Laing 909 series .

[MPMGinAL]

sorry i meant that we moved the txt not the heater. You probably figured that out on your own.

[JCsPlumbing]

Yeah, you might be right Alabama. That was my second guess. Since it is only the kitchen faucet I'm leaning toward that's the direction of the culprit. Pressure possibly pushing into the other side at different times when pressure increases. Put in thermal expansion tank and PRV.

[JCsPlumbing]

Some Laing series do exactly as you describe depending on the type. If it has a valve with it that goes to the farthest fixture then that's it.

[MPMGinAL]

I think i've got it!!!! I looked at the 909 on the net. It has a timer correct? What if its shutting off at night and not stopping water from pushing back through it? Maybe a check valve on your return lines?

[flat350]

The only reason that ther are 2 circ pumps is that after we roughed the house the owner decided that he wanted a recirc line to the kit. The area where the main in the basement was at was buried by duct and conduit by that time and we couldnt get another recirc line tied into It was easier to run a single recirc line to the kit .with it's own pump

[JCsPlumbing]

If I recall, there is more than one 909 series pump. Double check and make sure you have the right one. Some have check and bypass valves built into the head.

[flat350]

Well we even tried running the pumps all the time and then shutting them down at night , the problem we have with shutting the pumps down at all is that the builder told him that he would have instant hot water at any fct. in the house any time of day or night and if he doesnt he is a P.I.T.A

[MPMGinAL]

We will all probably want to slap ourselves in teh back of the head when you figure it out. Be sure and post the fianl conclusion. Good Luck and Happy Easter. Im going to bed.

[JCsPlumbing]

But he does have hot. It's just on both sides.:D Kidding. Tell us exactly how you have things piped for the recirculating line to the kitchen. Maybe I missed it.

[JCsPlumbing]

I'll go to bed when they pry that recirc pump from my cold dead hands.

[MPMGinAL]

If i didn't think that my toolbag would be a problem as carry-on i would come look for myself!! I want be there when someone say "well son of a *****"

[flat350]

I'll try to finish this tomorrow I dont want to go to sleep with a headache .

[JCsPlumbing]

You're fired.:mad: Just joking... I think we're in the right area though. Gonna be easier than repiping those water heaters. Happy Easter.:)

[Pete M]

You're fired.:mad: Just joking... I think we're in the right area though. Gonna be easier than repiping those water heaters. Happy Easter.:)

Let's assume all of the plumbing is in correctly and all of the return lines are seperately check-valved before the get to the pumps.

Let's also assume all single-handle fixtures are working properly.

You may want to check if any of the shower heads have shut-offs on them. Sometimes people turn of the shower at the head and leave the valves on. The water will mix

Another possibility is the washing machine. If they get debris in them not allowing them to close completely, you'll get a mix. The cold hose will get hot.

And make sure no one tied into a return line to feed a fixture.

[ToUtahNow]

A Watts #7 dual check has plastic checks and is not rated for hot water.

Mark

[sweatthepipe]

A Watts #7 dual check has plastic checks and is not rated for hot water.

Mark

Correct.

Use swing checks on circ pumps.

[sweatthepipe]

Also, make sure pump is installed in the right direction. Pumping BACK to heater.

Make sure return line is tied into cold inlet on heater, or directly to heater at drain. Not cold line away from heater or at manifold.

If it's tied into cold inlet, make sure the cold line has check valves.

[flat350]

# 1 - There are no single handle fcts. in the house except the kit. and tub valves , the tubs have thermostatic cartridges in them , all of the risers feeding the baths can be shut down so we know no water is crossing in that bath if we shut off the ball valves feeding it

# 2 - 100% positve that there are no crossed return lines ( visual before drywall , turned off cold feed to heaters and disconnected return lines from pumps , if a return line was tied into a cold line it would have backfed cold water to the pumps that didn't happen, made sure that there were't any checks preventing this also and with the cold valve off at the heater you only have water on the cold side of every fct. in the house )

# 3 - we tried a swing check on the cold main first and it didn't stop it

# 4 - We next tried a dual check on the cold main , it worked for a while

# 5 - We have tried the pumps on the cold feed ( w/checks ) and at the heater drain with checks

# 6 - pumps are both flowing in the correct direction

# 7 - Never thought about it crossing at the clothes washer ( we don't install them normally )

# 8 - We have tried it with a pump on each heater and both pumps on the first heater and then both pumps on the second heater

# 9 - The watts # 7 that we installed is rated to 180f so it should be OK with the 130f water that is backing up into the cold

# 10 - The Laing pumps we used do not have checks built into them but we did add them to the system

# 11 - This is a house that we did the groundwork in ,the rough piping and the trim , so we know how its piped and what the fixtures are , its not a service job that we picked up , thats whats goofy about it

# 12 - Last night I had my houses mixed up , this house has a TXT at the water heater ( we do the same homes for the same builder in different towns and each town has different codes .)

# 13 - Did the exact same house in another town one month later , same piping only difference is that the second house only has one pump and no recirc line to the kit. and everything works great in it ( thats why it seems like the second pump is the culprit )

# 14 - The circ line in the problem house for the kit. is tied into the hot line in the basement ceiling under the kit. cabinet and runs back to the water heater to its own dedicated pump nothing else is tied into it .

[Pete M]

# 1 - There are no single handle fcts. in the house except the kit. and tub valves , the tubs have thermostatic cartridges in them , all of the risers feeding the baths can be shut down so we know no water is crossing in that bath if we shut off the ball valves feeding it

# 2 - 100% positve that there are no crossed return lines ( visual before drywall , turned off cold feed to heaters and disconnected return lines from pumps , if a return line was tied into a cold line it would have backfed cold water to the pumps that didn't happen, made sure that there were't any checks preventing this also and with the cold valve off at the heater you only have water on the cold side of every fct. in the house )

# 3 - we tried a swing check on the cold main first and it didn't stop it

# 4 - We next tried a dual check on the cold main , it worked for a while

# 5 - We have tried the pumps on the cold feed ( w/checks ) and at the heater drain with checks

# 6 - pumps are both flowing in the correct direction

# 7 - Never thought about it crossing at the clothes washer ( we don't install them normally )

# 8 - We have tried it with a pump on each heater and both pumps on the first heater and then both pumps on the second heater

# 9 - The watts # 7 that we installed is rated to 180f so it should be OK with the 130f water that is backing up into the cold

# 10 - The Laing pumps we used do not have checks built into them but we did add them to the system

# 11 - This is a house that we did the groundwork in ,the rough piping and the trim , so we know how its piped and what the fixtures are , its not a service job that we picked up , thats whats goofy about it

# 12 - Last night I had my houses mixed up , this house has a TXT at the water heater ( we do the same homes for the same builder in different towns and each town has different codes .)

# 13 - Did the exact same house in another town one month later , same piping only difference is that the second house only has one pump and no recirc line to the kit. and everything works great in it ( thats why it seems like the second pump is the culprit )

# 14 - The circ line in the problem house for the kit. is tied into the hot line in the basement ceiling under the kit. cabinet and runs back to the water heater to its own dedicated pump nothing else is tied into it .

Has anyone tried isolating the washing machine by shutting off the laundry bibbs?

[JCsPlumbing]

Put in expansion tanks. Should be in anyway. If it doesn't fix it then you've added protection. If it does correct it then you've still added protection. I'd also put gauges on the hot and cold sides to test for pressure differences with the pumps on and off & to see what the actual pressure is from the street.

It might be an AHA! for some of us if we saw pictures. Maybe.

Anyway, please post when you correct the problem as to what you did.

[plumberscrack]

Flat350,

Do you solemnly and sincerely and truly declare and affirm that the evidence you shall give shall be the truth, the whole truth and nothing but the truth?

If so, please answer these questions:

The hot water comes out of only the kitchen faucet? Nowhere else?

You have a circ pump at water heater that tees off kitchen hot water line in ceiling underneathe? Pump serves only kitchen sink?

This 5-1/2 bath house has only 1 kitchen sink?

This only happens after being stagnate for several hours?

How long does the hot/warm water come out of cold side before turns back to all cold?

It does turn back to all cold, right?

Where exactly is the Watts 007 installed?


No further questions at this time Your Honor

[Australian Plumber Josh]

I second the idea of a cross connection . Clothes washer / dishwasher or the affected kitchen sink tap.

very interesting.

[DuckButter]

I finally read enough to list some questions, but the talented Mr Crack beat me to 'em.
The fact that a double check resolved the issue for 5 months tells us something.

I think both Pete and JC may have the solution, it would seem that thermal expansion has worked it's way through a fixtures seals over the time the double check was installed...laundry valves are a common culprit.

I'd ask the owner to shut off the laundry, & cold shutoff at the kitchen for a night and see what results that yields...also consider the possibility that the sink faucet itself is allowing backflow under unusually high pressure from the hot side.

Another thought, the recirc line was added after the finish, so I assume this isn't likely, but could the recirc line be in contact with the cold line to the kitchen at any point?

[NHMaster3015]

Absolutly correct the Ducky. Anytime you close off the hot water system through use of a check-valve, as the water expands it has no place to go, so it takes the path of least resistance which would be up the cold water line. A Thermal expansion tank will undoubtly fix the problem.

[TOPDAWG]

I finally read enough to list some questions, but the talented Mr Crack beat me to 'em.
The fact that a double check resolved the issue for 5 months tells us something.

I think both Pete and JC may have the solution, it would seem that thermal expansion has worked it's way through a fixtures seals over the time the double check was installed...laundry valves are a common culprit.

I'd ask the owner to shut off the laundry, & cold shutoff at the kitchen for a night and see what results that yields...also consider the possibility that the sink faucet itself is allowing backflow under unusually high pressure from the hot side.

Another thought, the recirc line was added after the finish, so I assume this isn't likely, but could the recirc line be in contact with the cold line to the kitchen at any point?

I told him this a while back and he made it seem that i was nuts for even suggesting it. I say once he figures it out he can come back and tell us what he figured out!! He doesn't seem to want to try any of our suggestions.

[plumberscrack]

# 12 - Last night I had my houses mixed up , this house has a TXT at the water heater ( we do the same homes for the same builder in different towns and each town has different codes .)

What say you boys now?:scratchhead:

[DuckButter]

As interesting as these trouble shooting threads can be, there's a frustrating flip side.
Hands on
Nothing so fun as asking for a detail and waiting a day or two, or attempting to decipher through one interpretation, including personal error on the part of the o/p.

I still say it's backfeeding from a fixture, add to the fact that the recirc line will be subject to expansion along with the total mass of two 50 gal tanks being heated and I betcha something is giving from pressure, pushing back into the cold line.

Sooooo many things come into play, such as whether the T&P's are letting off?
Can the owner hear lines ticking or squeaking from expansion? (unless they're PEX)
What temperature are the heaters set to?
What other fixtures branch off the lines before the kitchen?
Who's on first...and where do babies come from?

IF there aren't expansion tanks, then I wager that would resolve the issue.

At this point, I'm almost ready to take a flight out just to look at the dam thing myself!

Then there's the ultimate frustration, never hearing from the o/p as to what actually was the problem in the end.

[HVAC HAWK]

Put in expansion tanks. Should be in anyway. If it doesn't fix it then you've added protection. If it does correct it then you've still added protection. I'd also put gauges on the hot and cold sides to test for pressure differences with the pumps on and off & to see what the actual pressure is from the street.

It might be an AHA! for some of us if we saw pictures. Maybe.

Anyway, please post when you correct the problem as to what you did.

i think jc said it once or20 times to put in expansion tanks in :shrug::smack-head::clapping:

[DuckButter]

What say you boys now?:scratchhead:
If so, did he pressurize it according the the system?

[DuckButter]

i think jc said it once or20 times to put in expansion tanks in :shrug::smack-head::clapping:
Took me a couple of thunderous slaps on da head, TXT = Thermal eXpansion Tank....duh.

[JCsPlumbing]

Hmmmmm :confused: Missed that one PC. Something tells me we need a pic.

But I will say that a bleed over from pressure can only happen at a weak point. So if they have access to the lines when the cold line is hot they should be able to locate that weak point pretty quick. If the cold line is hot only at one fixture that gets hot/cold then that fixture is the culprit for whatever reason.

And he keeps saying over and over that it's only the kitchen faucet. IF this is true then that's the weak point. Put in a different kitchen faucet?:confused:

But I'm still suspicious. Both he and we have solved all issues available to the laws of physics. Personally, I'm at the point where I need to see it. Just suspicious I guess. It just seems somethings missing. Based on the info and all the solutions this should be easily corrected.

[JCsPlumbing]

And I said before... this is what I consider a plumbing diagnosis quiz. :)

[DuckButter]

Hmmmmm :confused: Missed that one PC. Something tells me we need a pic.
Few months back, we tried that with someone having trouble on a gravity recirc system.
We got pics that showed small sections of the pipe, but still left us relatively clueless...asking even more questions.

I honestly think there is a detail we covered that may have been missed with Flat350.
I don't blame him, I get to that point myself sometimes...when you get so frustrated that you miss one minute yet obvious detail while you scramble trying to remedy the problem.

[NHMaster3015]

The introduction of backflow preventers and check valves has caused many problems since their introduction and most of them are caused by thermal expansion. Many times the relief valve on a water heater will weep and the plumber will change it out only to have the problem return. Leaking backflow preventers can also be linked to the same problem. Any time water is heated, it expands. In the days before backflow preventers the expansion would migrate back into the water lines and cause few visible problems. Now of course the private water system is sealed at the BFP, so any pressure increases within the system are going to occur within the system. Many times the customer will complain of a sudden spitting or excess water pressure for a second or two after opening a faucet. Or a toilet fill valve that spits and gurgles when the toilet is flushed. All symptoms of thermal expansion. Diagnosis is fairly simple. Install a good pressure gauge in the system and then take a couple before and after readings. The results can be very surprising. I have seen as much as a 40 lb pressure increase in the off cycle.

[JCsPlumbing]

The introduction of backflow preventers and check valves has caused many problems since their introduction and most of them are caused by thermal expansion. Many times the relief valve on a water heater will weep and the plumber will change it out only to have the problem return. Leaking backflow preventers can also be linked to the same problem. Any time water is heated, it expands. In the days before backflow preventers the expansion would migrate back into the water lines and cause few visible problems. Now of course the private water system is sealed at the BFP, so any pressure increases within the system are going to occur within the system. Many times the customer will complain of a sudden spitting or excess water pressure for a second or two after opening a faucet. Or a toilet fill valve that spits and gurgles when the toilet is flushed. All symptoms of thermal expansion. Diagnosis is fairly simple. Install a good pressure gauge in the system and then take a couple before and after readings. The results can be very surprising. I have seen as much as a 40 lb pressure increase in the off cycle.

True NH. I've seen this too. Flat350 should check the pressures on both sides at the end of the water heaters' firing cycle with the pumps on. That might help point him to a solution.

[JCsPlumbing]

I can't imagine hot on the cold side just being at the kitchen faucet and nowhere else.
Icemaker?:confused: Grohe faucet design problem?:confused: Been told some kitchen faucets have pressure/temp controls now.

But if it IS as you say then I have one last suggestion. (We hope!)

Put a good check valve underneath the kitchen sink on the cold side. Might not solve the mystery, but might solve the problem. Please post what you do.

J.C.

[flat350]

Haven't been by the computer since Sun. morn. , YES the house does have a TXT on the first heater . As soon as my service guy can sch. an app. to get into this P.I.T.A. house he's going to try the laundry first and probably try a new cartridge in the kitchen second.Not both at the same time , I want to know if it's the laundry , kitchen or whatever causing the problem. Somebody made a comment about feeling the pipe to try to isolate it , as you stand by the first heater with your hand on the cold feed you can feel the warmth slowly creep up the line and work it's way into the overhead horizontal line headed to the kit. after 90 min. or so . IF I HAD OR COULD GET PICS. I WOULD POST THEM IN A HEARTBEAT but this nut doesn't really even want us in his house , it's also a finished basement about the only thing you would see is the heaters , so my service guy has been dealing with him . This isn't my first install like this I've done hundreds , not being snippy I'm just tired of dealing with this .When you think that you have it fixed and then it decides to rear it's ugly head again .The check valve at the kit. sink may be an option too.
TOPDAWG the kit. recirc line was added after the rough but before trim , we could get at the kit. lines in the area of the basement under the sink but not at the main and the return line is piped to the heaters about 15 joist bays away from where the hot and cold lines are located. there is no way that any of them are touching . If I can get my scanner up and running I could probably get a drawing done that would show exactly how they are piped , and the option of a different type of a kit. fct would never fly with this homeowner. When they built this house they tore all of the cabinets and hardwood floors out because the homeowner decided that he didn't really like the original finish that he had OK'd and chosen , this was done at the builder cost not the homeowners ( they already had a lot of money in the house and they found out he gave the last builder that he worked with a very difficult time with attorneys ) . this isn't a small house either probably 6000 + sq. ft = lots of wood and cabinets , he's a P.I.T.A.

[HVAC HAWK]

its just like the others are saying it is hard to figure this out with out hands on .
and being you cant go and try something and we can see what that does makes it even harder . :shrug:
watch it will be some thing so simple :D but we will keep trying

[flat350]

Well I'm going to have my head examined now ( dentist appt. ) I'll try to check back later tonight .

[ToUtahNow]

flat350,

Just as a suggestion, even a cheap laser thermometer would make finding the problem much easier for you. I use a Raytek MX4 and it sure makes me look smarter than I am when solving such problems.

Mark

[OkieBill]

Some random thoughts that come to mind

--Could you have a simple case of conductive / convective heating of the cold water line?
--Recirc is keeping the line warm all night, If the pipes were installed very close together could it be heating the cold water line inside the walls??

--Is the water only hot from the cold line in the mornings and for only a short time???

Are the hot water lines insulated:-)

If I missed these details in the thread please forgive...

:D

[MPMGinAL]

Still Just throwing things out there. Is there just one expansion tank? Is it a 2 gallon or 5? They have ratings as to what size heater they willl serve. Its easy for someone to throw in a smaller cheaper tank and it would probably go un-detected by inspector. I think the 2 gal is rated at 50 gallons so if you have 2 heaters you would need larger of the two.

Also, i don't know why this would matter, but its the HVAC tech coming out in me, have you checked the amp draw on the circ pumps?

Have you said whether they are gas heaters or electric?

[DuckButter]

Somebody made a comment about feeling the pipe to try to isolate it , as you stand by the first heater with your hand on the cold feed you can feel the warmth slowly creep up the line and work it's way into the overhead horizontal line headed to the kit. after 90 min. or so .

That leaves just one question...Is there anything tee'd off that cold line before the kitchen, after the heater?
Put a gauge on the line and see what it gets up to while the tank heats, you might get a second exp tank on top of replacing the cartridge.
I feel for ya...knots in my stomache just imagining your situation.

[mtnman1100]

I agree with WCP, could be crossing over in a cartridge style shower/tub valve. What types of shower/tub valves are installed?

[flat350]

I'm going to let this rest for awhile and try some of the suggestions , might be a week or so til we get into the house . Thanks for the ideas and i'll post if we come up with a positive solution . Many people have asked questions about whats in the house and if you read the entire thread you'll find the answers hvae ben discussed in a prior post .

[JCsPlumbing]

Wonder what happened with this. Lot's of people don't post results or solutions.

I need my money on the nightstand in the end. :(

J.C.

[Ace Sewer]

Wonder what happened with this. Lot's of people don't post results or solutions.

I need my money on the nightstand in the end. :(

J.C.

yes!... this was a good one... flat? what happened?

[flat350]

Seem's that the H/O has been out of the country on business , of course we have not been able to get back into his house because of that . I'll post when we do get in and if we really find a solution , got some different ideas from this post to try .

[flat350]

I know it's been a long time since this was posted . The only thing that we did in addition to all of the other things that we had tried was to insulate all of the cold line leading to the kitchen , it seemed to stop the problem . When we thought about it ,the complaints about the water temp. came during heating season and not during cooling season it had to be heat transfer from the ductwork .I had an opportunity to talk to the builder this week and asked him if it was still a problem and he said the HOMEOWNER is a problem and that he won't ask us to to look at it again and waste our time ( seems the H.O has been an unrealistict P.I.T.A to the builder ) .

I'm not sure if we fixed it for sure but at this time as long as the builder is happy I'm allright with it because he pays my bills not the homeowner