# Positemp question.



## jmc12185 (Aug 27, 2013)

When you turn Positemp to hot, it runs hot for a few seconds than starts cooling off. Everything else in the house runs fine. HO said it started happening a few weeks ago. I tried 3 different cartridges and same thing. Also, the faucet in same bathroom runs hot enless I run tub and faucet together. Than I get cold out of hot side. The cold water is mixing through somehow. Any ideas?? It's a tankless coil on the boiler.

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## rjbphd (Feb 5, 2010)

jmc12185 said:


> When you turn Positemp to hot, it runs hot for a few seconds than starts cooling off. Everything else in the house runs fine. HO said it started happening a few weeks ago. I tried 3 different cartridges and same thing. Also, the faucet in same bathroom runs hot enless I run tub and faucet together. Than I get cold out of hot side. The cold water is mixing through somehow. Any ideas?? It's a tankless coil on the boiler.
> 
> Sent from my iPhone using PlumbingZone


Mixing valve at boiler acting up??


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## PlungerJockey (Feb 19, 2010)

Sounds like it maybe a bad check valve.


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## jmc12185 (Aug 27, 2013)

rjbphd said:


> Mixing valve at boiler acting up??


 why just that shower though? They have 3 other bathrooms in house and everything's fine. I feel like it's something wrong with the valve body but don't want to bring up replacement if there's a simple solution.

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## rjbphd (Feb 5, 2010)

jmc12185 said:


> why just that shower though? They have 3 other bathrooms in house and everything's fine. I feel like it's something wrong with the valve body but don't want to bring up replacement if there's a simple solution.
> 
> Sent from my iPhone using PlumbingZone


Hmmms, when u pulled the pos cartridge out.. did you get ALL the rubber out?? A little piece left inside will create havoc.. I wouldn't mind explaining Moentrol to them.. did one replacment and got called back to replace the rest of pos Postitemp


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## CTs2p2 (Dec 6, 2011)

Start shutting off hot side angle valves till you find which fixture is crossing cold into hot line...

Start closest to shower and work away checking shower temp after each closed stop..


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## jmc12185 (Aug 27, 2013)

CTs2p2 said:


> Start shutting off hot side angle valves till you find which fixture is crossing cold into hot line... Start closest to shower and work away checking shower temp after each closed stop..


 the problem has to be with the positemp. Everything works fine until you open that valve. I'm just going to replace it. I can get to it from closet behind.

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## Leach713 (Nov 1, 2013)

Mess with temperature limit stop.


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## Leach713 (Nov 1, 2013)

Leach713 said:


> Mess with temperature limit stop.


. 
I meant adjust it


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## jmc12185 (Aug 27, 2013)

Why is it that the last stop of the day is always the b!tch.

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## Letterrip (Jul 28, 2013)

Moen single handle faucets are notorious for cross connecting hot and cold internally even when they are turned off. (Old ones at least)


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## ASUPERTECH (Jun 22, 2008)

Best to find that cross connection, you won't look good if your new valve does the same...


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## Leach713 (Nov 1, 2013)

My old company would of sold them a whole house repipe with a carbon filter


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## jmc12185 (Aug 27, 2013)

ASUPERTECH said:


> Best to find that cross connection, you won't look good if your new valve does the same...


 won't look good at all. That's what I'm afraid of.

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## CTs2p2 (Dec 6, 2011)

jmc12185 said:


> won't look good at all. That's what I'm afraid of. Sent from my iPhone using PlumbingZone



Is it a single handle lav faucet in that bathroom?
I'm with letterrip, it's probably a moen.. Bring a 1200 cartridge with you. 

I've seen it specifically on a tankless coil, not effect other fixtures that are tied in before and only effect fixtures after. So let me guess is this bathroom group last on the line? Maybe shower is only thing piped after the bad sink cartridge?


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## jmc12185 (Aug 27, 2013)

CTs2p2 said:


> Is it a single handle lav faucet in that bathroom? I'm with letterrip, it's probably a moen.. Bring a 1200 cartridge with you. I've seen it specifically on a tankless coil, not effect other fixtures that are tied in before and only effect fixtures after. So let me guess is this bathroom group last on the line? Maybe shower is only thing piped after the bad sink cartridge?


 You might be onto something here!!

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## jmc12185 (Aug 27, 2013)

Thanks for all the input. Much appreciated. I'll let you know how it works out.

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## Tommy plumber (Feb 19, 2010)

PlungerJockey said:


> Sounds like it maybe a bad check valve.












I had that exact scenario some years back; a lady would get little blasts of hot water out of her master bath lav faucet while brushing her teeth (she only had the cold tap open) in the morning. It was a defective check on her fancy shower valve. When I replaced the check on her shower valve, problem solved. It was a mansion on the beach with hot water re-circ pumps. The pumps will tend to push water against the grain.


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## ASUPERTECH (Jun 22, 2008)

Start the isolation processes. Don't forget the washing machine, ask what projects may have been completed recently. I just found a cross where the soon was helping out mom, demo'ed her utility sink, and directly crossed the hot and cold, the only fixtures effected, were the k.s. and w/m. She hadn't noticed the w/m.


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## Letterrip (Jul 28, 2013)

Had one a long time ago where a two handle shower valve had been capped at the head. The shower was used as storage. Over the years of moving boxes, both handles eventually got bumped open.


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## ASUPERTECH (Jun 22, 2008)

Letterrip said:


> Had one a long time ago where a two handle shower valve had been capped at the head. The shower was used as storage. Over the years of moving boxes, both handles eventually got bumped open.


Yep seen almost the same, they used it still, but dad had"fixed" a leak on a 2 handle, with a 1/2" ball valve... Had to laugh...


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## rjbphd (Feb 5, 2010)

Leach713 said:


> My old company would of sold them a whole house repipe with a carbon filter


Huh?? Sounds like a scam artist??


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## Redwood (Sep 8, 2008)

rjbphd said:


> Mixing valve at boiler acting up??


I'd look at that...
As well as maybe the coil on the boiler needing a cleaning...

Often it doesn't show until the tub is filling...
There isn't another faucet in a home that flows as much as the tub...

Crank up the tub and let it get cold then check the temperature coming out of the coil and out of the tempering valve...

Where you lose the hot is where the problem is...

I'd check there first before going crazy changing cartridges thinking its a crossover problem....


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## Leach713 (Nov 1, 2013)

rjbphd said:


> Huh?? Sounds like a scam artist??


If you only knew sir....


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## Letterrip (Jul 28, 2013)

Redwood said:


> I'd look at that...
> As well as maybe the coil on the boiler needing a cleaning...
> 
> Often it doesn't show until the tub is filling...
> ...


If I ever move north, I'll be in a world of hurt trying to learn boilers. Never worked on one in my life.


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## rjbphd (Feb 5, 2010)

Letterrip said:


> If I ever move north, I'll be in a world of hurt trying to learn boilers. Never worked on one in my life.


Know thy hartford loop and drop header...


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## plumberpro (Jan 1, 2013)

Is there a mixing valve on the toilet? some homes had them to prevent the tank from sweating that will also cause a cross connection


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## HSI (Jun 3, 2011)

Make sure you use OEM cartridges. Some of the aftermarket cartridges suck.


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## love2surf927 (Dec 22, 2011)

HSI said:


> Make sure you use OEM cartridges. Some of the aftermarket cartridges suck.


I've had brand new aftermarket posi temp cartridges leak. (HO supplied) learned my lesson.


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## rjbphd (Feb 5, 2010)

love2surf927 said:


> I've had brand new aftermarket posi temp cartridges leak. (HO supplied) learned my lesson.


Postitemp sucks in 1st place...


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## plbgbiz (Aug 27, 2010)

rjbphd said:


> Postitemp sucks in 1st place...


Of course it does. It's made by Moen. :laughing:


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## duece (Dec 15, 2013)

seen water cross over in washing machine once. turn off hose bibs and see if it helps


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## rjbphd (Feb 5, 2010)

plbgbiz said:


> Of course it does. It's made by Moen. :laughing:


Up urs... M\ontrol.


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## rjbphd (Feb 5, 2010)

duece said:


> seen water cross over in washing machine once. turn off hose bibs and see if it helps


So how do you know this much ??


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## duece (Dec 15, 2013)

rjbphd said:


> So how do you know this much ??


Been plumbing long time. How bout you rjbphd?


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## ASUPERTECH (Jun 22, 2008)

duece said:


> Been plumbing long time. How bout you rjbphd?


Here we go...


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## rjbphd (Feb 5, 2010)

duece said:


> Been plumbing long time. How bout you rjbphd?


Where does it say you been plumbing a long time in your introduction??


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## MTDUNN (Oct 9, 2011)

duece said:


> seen water cross over in washing machine once. turn off hose bibs and see if it helps



Hose bibs in a washing machine setup? And if so, only need to turn one off. Not both


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## Redwood (Sep 8, 2008)

I've seen this type of washing machine valve crossover....


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## plbgbiz (Aug 27, 2010)

Just convert the clothes washer over to a cross-connection-proof system.


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## Best Darn Sewer (Dec 23, 2012)

rjbphd said:


> Postitemp sucks in 1st place...


Ol' RJ, never one to miss an opportunity to put down positemp and promote Moentrol. I like Moentrol, also. Isn't that the one where the balancing spool is separate and it uses the old 1200 cartridge? Or the old pull-out and push-in style?


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## Best Darn Sewer (Dec 23, 2012)

Redwood said:


> I've seen this type of washing machine valve crossover....


Never saw one of those til I moved to Montana. They seem like a great idea except you can't shut off just one side. They are illegal in Texas.


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## rjbphd (Feb 5, 2010)

Best Darn Sewer said:


> Ol' RJ, never one to miss an opportunity to put down positemp and promote Moentrol. I like Moentrol, also. Isn't that the one where the balancing spool is separate and it uses the old 1200 cartridge? Or the old pull-out and push-in style?


 Yeap ... can use the 1225 cartiridge in same Moentrol..


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## Best Darn Sewer (Dec 23, 2012)

rjbphd said:


> Yeap ... can use the 1225 cartiridge in same Moentrol..


OK, the 1225 cartridge. I can never remember the numbers for all the different cartridges. That's my favorite one. Simple and it can easily be removed years later. You don't see Moentrol here in Houston often. Up north it seemed more popular. Moentrol may be a better faucet but we get more work from the positemp...and a work out trying to pull those bast***s out.


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