# low pressure hot side.



## AKdaplumba (Jan 12, 2010)

This townhouse is 4 years old, every fixture on the hot side has lower pressure then the cold. Like much lower. When you run the hot it looks like pressure tapers off a bit. Ive come to the conclusion that its either a kinked line near the tank or the tank itself. My question is how can you trouble shoot the tank?


I think it's been doing the same thing since day one but only noticed it using the roman tub and main bathroom tub for the first time in 4 years. 

Thx.


----------



## justin (May 14, 2010)

Not a tankless? Is valve open all way? It is probably a simple fix.


----------



## justin (May 14, 2010)

I usually bypass tank with washing machine supplies and see if it is after or before tank.


----------



## seanny deep (Jan 28, 2012)

Hot water tank braided supply and two reuseable sharkbite mips. will bye pass the heater quickly. Or is there diaelectric unions on the tank. That or Whats the water supplied from here We have white iron witch only solidifys when heated. Some times fixture supply lines get plugged up. Or sawdust inlines from roughin check the cartdridges. Usually something stupid. Last but not least I know it sounds stupid but make sure the hots not plumbed out of the cold side of tank found this on a local condo once.


----------



## Woodman1 (Mar 10, 2012)

Does the W/H have heat trap nipples?


----------



## user2090 (Sep 26, 2009)

Most likely there is a build up on the hot side nipple, dielectric, or direct copper connection. Check the top side of the heater hot side out let for junk. Just had that happen where a dummy put male copper directly into the tank. But that out showed H.O. and he was amazed that something like that could happen.


----------



## Michaelcookplum (May 1, 2011)

seanny deep said:


> Hot water tank braided supply and two reuseable sharkbite mips. will bye pass the heater quickly. Or is there diaelectric unions on the tank. That or Whats the water supplied from here We have white iron witch only solidifys when heated. Some times fixture supply lines get plugged up. Or sawdust inlines from roughin check the cartdridges. Usually something stupid. Last but not least I know it sounds stupid but make sure the hots not plumbed out of the cold side of tank found this on a local condo once.


According to "old school" (idiot) you must be certified to use SB fittings.


----------



## rocksteady (Oct 8, 2008)

Pop the the t&p. If water runs out at full pressure, it's clogged on the hot nipple. If it runs out at the same pressure you're getting at the fixtures, it's the cold nipple.





Paul


----------



## AKdaplumba (Jan 12, 2010)

It's pex coming out of the wall, 18 inches of copper. No dielectric union or heat trap nipples or anything else fancy. 

Good stuff, I will check it out on the weekend.


----------



## user2090 (Sep 26, 2009)

AKdaplumba said:


> It's pex coming out of the wall, 18 inches of copper. No dielectric union or heat trap nipples or anything else fancy.
> 
> Good stuff, I will check it out on the weekend.



I bet when you pull that direct connection you will find your problem. That is against code to not have some kind of dielectric on the heater, and a union has to be within 12".


----------



## azmike (Feb 3, 2010)

Is the inlet valve a gate or a ball? I've found alot gates broken and only partially turned on.


----------



## brezzz (Feb 7, 2012)

check valve , make sure it full port.


----------



## markb (Jun 11, 2009)

Check temp on Hwt outlet, faulty mixing valve and high tank temp will dissolve minerals in water and clog up arrators, check-stops, and basin supplies. Softner doesn't help either. Seen in a few homes before.

Sent from my iPod touch using PlumbingZone


----------



## AKdaplumba (Jan 12, 2010)

Indie said:


> I bet when you pull that direct connection you will find your problem. That is against code to not have some kind of dielectric on the heater, and a union has to be within 12".


I am sure it's built in. Otherwise we would never pass inspection. 

What would cause a build up? Something in the water? I know B.C. has aggressive water. 

Other question is why only this unit?


----------



## bartnc37 (Feb 24, 2009)

I'm guessing someone soldered the fip adapters when they were already threaded on and melted the plastic lined nipples partially closed, could be hot or cold side. Just throwing it out there because I've seen it before.


----------



## Tommy plumber (Feb 19, 2010)

Maybe someone went around and closed all the hot angle stops to mess with you......:laughing:


On a serious note, is the hot water piping undersized? 

Or like everyone else has stated (including OP'er) obstruction and/or kinked line.


----------



## TPWinc (May 30, 2011)

rocksteady said:


> Pop the the t&p. If water runs out at full pressure, it's clogged on the hot nipple. If it runs out at the same pressure you're getting at the fixtures, it's the cold nipple.
> 
> 
> 
> ...


That's where I'd start by poping the T&P, but it could be more to it than just the nipple. Could be a manifold or a dip tube. If the pressure is good at the T&P... I would try back flushing the WH. If you have a thermal expansion tank on the cold side, repalce it with a threaded hose bib to use as an outlet and back flush the dip tube too.


----------



## damnplumber (Jan 22, 2012)

I had one like this many years ago and found galvinized nails in the copper piping. You can guess what happened over time when electrolisis occurred. But I agree with most here...start with the water heater. Let us know what you found OK?


----------



## AKdaplumba (Jan 12, 2010)

This is what I found....

Low pressure on the hot side, took the vac breaker off and lots of pressure so it's not the ball valve or supply. Low pressure coming out of the T+P.

Something is wrong with the tank itself. It's a John Wood, gas supplied tank. It's under manufacture warranty so i am leaning toward the HO getting a free replacement.


----------



## Juice (Nov 17, 2008)

If its a rheem, there is a ball in the cold inlet that acts as a check valve and gets stuck causing low hot pressure.. disconnect female adaptor and pull out ball with needle nose pliars. can be a bit of a ***** but it will come out without damaging dip-tube .. sorry, just noticed you said its a JW.. not sure if they have the same design.. easy to look into it though


----------



## rocksteady (Oct 8, 2008)

AKdaplumba said:


> This is what I found....
> 
> Low pressure on the hot side, took the vac breaker off and lots of pressure so it's not the ball valve or supply. Low pressure coming out of the T+P.
> 
> Something is wrong with the tank itself. It's a John Wood, gas supplied tank. It's under manufacture warranty so i am leaning toward the HO getting a free replacement.


What could be wrong with the tank? It's a tank. How is the HO going to get a free tank unless you lie and say it's leaking? 

I'm not familiar with John Wood tanks but heat trap nipples or check valve nipples can cause these problems. I'd pull the cold connection and check for a ball. It'll be flat on the tank side and have a stalk on the other end so you can grab it with a pair of needle nose pliers and pull it out. They are notorious for getting stuck and restricting flow.




Paul


----------



## jredman45 (Mar 30, 2012)

I have found on a coupleof ocassions that the dip tube has disentigrated. After this happens all the little bits of plastic will travel through the system and clog aerators and shower heads and shutoff valves. Also gets into cartridges and balls of delta faucets. 
Fixed the problem by replacing heater and flushing the lines really well and making sure everything was unclogged. Takes some time.


----------



## plumbtekkk (May 19, 2012)

mabey take out the heat trap in the w/h


----------



## johnlewismcleod (Apr 6, 2012)

markb said:


> Check temp on Hwt outlet, faulty mixing valve and high tank temp will dissolve minerals in water and clog up arrators, check-stops, and basin supplies. Softner doesn't help either. Seen in a few homes before.
> 
> Sent from my iPod touch using PlumbingZone


Tub spouts don't have aerators.


----------



## bizzybeeplumbin (Jul 19, 2011)

johnlewismcleod said:


> Tub spouts don't have aerators.


Some expensive ones do. Even some of the Kohlers have aerators.


----------



## futz (Sep 17, 2009)

AKdaplumba said:


> This is what I found....
> 
> Low pressure on the hot side, took the vac breaker off and lots of pressure so it's not the ball valve or supply. Low pressure coming out of the T+P.
> 
> Something is wrong with the tank itself. It's a John Wood, gas supplied tank. It's under manufacture warranty so i am leaning toward the HO getting a free replacement.


Take the tank connections apart, one at a time, and look for corrosion junk clogging the inlet or outlet. They have those heat traps in there that tend to clog up. Last one I fixed I had dielectrics on it, so I just took one apart (cold side) and poked in there with a screwdriver to free it up. That cured it, and I haven't heard back from them (the landlord there is a regular customer, so I would hear from him if there was a problem). I was surprised that it was so easy to fix.


----------



## futz (Sep 17, 2009)

Indie said:


> That is against code to not have some kind of dielectric on the heater, and a union has to be within 12".


Might be against code where you live, but it's not required by code here in B.C. (where AKdaplumba works). They haven't been required since I was a very young apprentice, many decades ago. I use dielectrics mostly just to impress the inspectors, and because I like them. They're junk, but no worse than copper FIP adapters on the nipples, which is what most plumbers around here do.


----------



## rydinhood (May 22, 2012)

Hey you guys.. We've had problems w/ tempering valves installed where they're inaccessible, no one knows they're there, and there's major restriction in the hot water delivery..If there are no heat trap nipples, I'd be looking for a concealed tempering valve.


----------



## MTDUNN (Oct 9, 2011)

rocksteady said:


> Pop the the t&p. If water runs out at full pressure, it's clogged on the hot nipple. If it runs out at the same pressure you're getting at the fixtures, it's the cold nipple.
> 
> Paul


I agree but if you pop the T&P, be prepared to replace it.


----------



## MTDUNN (Oct 9, 2011)

Juice said:


> If its a rheem, there is a ball in the cold inlet that acts as a check valve and gets stuck causing low hot pressure.. disconnect female adaptor and pull out ball with needle nose pliars. can be a bit of a ***** but it will come out without damaging dip-tube .. sorry, just noticed you said its a JW.. not sure if they have the same design.. easy to look into it though


Or just replace heat trap nipple with brass


----------

