Hot water first floor, luke warm water second floor

Xmytruck

Hello

I have one navien ch 240 with a circulating pump for the second floor about two weeks ago we got luke warm water upstairs and hot water down stairs. For the last two days it has been consistent where upstairs I only get luke warm water, once in a while I will shut down the circulating pump and then I get hot water. But ten minutes later luke warm water with the pump off. I am completely baffled on what the issue could be. This did not happen last year.



thx

Snowmelt

Did

You call tech, did you ever have the unit serviced

Did you have any error codes.,

A few things come to mind, did you check your fixtures for bleeding?

Do you have servicing valves?

Xmytruck

temp

Had the tech come out in the winter because of a clog intake, I just notice that I only shut down the motor on the circulator pump not the value on the return. I am going to try that for a day and see what happens. My thought is that the aqua stat temperature is set to high and is pulling the hot water back to the unit, The unit is not adjusting the temperature because the return is already hot, so the water getting returned to the shower is luke warm. Note I am not plumber so let me know if I am even close.



thx

Snowmelt

Anything is possible

With that being said, are you able to read the water temperature comming out of the machine?

I was confused by last post. We have to start from original position of all valves and pumps.

Zman

Cross Connect

It i quite possible this has nothing to do with the Navien.

If you have a connection between hot and cold anywhere in the house, it can cause the problem you are having. Common causes are a hose "Y' going from hot to cold on a faucet. It could also be caused by a shower head shutoff valve or faulty appliance like a washing machine. What has changed?

Carl

Xmytruck

temp reading

Yup the reading from the navien is 135, I have the temp set to 120, the facet downstairs measures 121.

Xmytruck

Change

That the weird thing nothing was changed in the plumbing system. The only reason I thought it can not be the navien system is because the first floor is getting hot water and the hot water pipe that feeds the first floor does branch off to the second floor where the aqua stat and return to the pump is installed.



What does not make sense is that one out of 10 times we get hot water upstairs, I can not explain that. Pump seems to be running, navien is running, DHW pipe is hot, pipe going to the second floor is warm and the return pipe is warm.



Normal operation is I expect the DHW pipe is hot, the pump off and pipe going to the second floor to be hot and the return to the pump to be cold.



Shut off the value on the return to the pump and shut down the pump motor, had hot water this morning, I will see how that goes.

Charlie from wmass

is there a check valve

on the recirculation line? If so is it working? Run the water to the offending faucet and see if any hot water lines are running cold or any cold lines are getting warm.

Charlie from wmass

is the pump

installed pumping the right way? what style of pump are you using? can you shut the recirculating pipe and see if the water turns hot going to the second floor?

hot_rod

3 way mix valve?

in the piping?

Zman

Picture

I think a picture of the circ pump piping would help...

Charlie from wmass

Hot Rod I bet it is just

a mixing valve like the AM10.

Xmytruck

Shut off

I did shutoff the return to the pump and so far I have hot water. I am going to check when I get back home.

Charlie from wmass

buy a brick

http://www.heatinghelp.com/products/Buy-a-Brick/32/172/Buy-a-Brick



then buy a new check valve for the return line.

Xmytruck

Pics

Pic of the work,

Charlie from wmass

please read item #2

in the following link.

http://www.taco-hvac.com/uploads/FileLibrary/102-054.pdf

Xmytruck

Awesome

Quality work

Charlie from wmass

it is an easy fix at least

direction are included in the link above to fix that.

Snowmelt

The two

Thinks I don't like .



1. The cheap air scoop instead of a nice air seperator

2. No potable expansion tank.

3. Why the black pipe.

Charlie from wmass

the cheap scoop I can explain

I know many people who suffered from leaks from the "good" air separators, including my self. The iron pipe was to keep it neat and save on material costs. the recirculator motor not turned properly and I am guessing no check valve in it or on the line is a clue the burner was not checked with a combustion analyzer either.

icesailor

Working, then not:

It worked for a year, now it doesn't. The motor being backward/upside, down shouldn't matter. If the arrow on the casting is going the right direction, shut off the water so there is no pressure on the mu,p. Take a 5/16" nut driver and undo the 4 nuts. flip the motor assembly 180 degrees. While you're at it, check the vanes on the impellor. They are usually a white plastic. They can be worn or broken off. That will keep it from circulating properly and not develop enough head pressure.

If you have a Moen shower valve on the second floor, take the cover off and see if the valve is hot or cold when it isn't running. The check/stops may be bad.

Charlie from wmass

no Ice the motor mean nothing to the problem

I just pointed it out to gauge the installers lack of detail as when the seal goes it will leak into the electrical box and cause issues. The poster closed the valve on the recirculating line and the water got hot. I am betting on a bad check valve.

Xmytruck

Check valve

Is this the check valve

Snowmelt

Nope

That's a flushing port with what looks like it had a shut off handle on it. I would be embarrassed with that on any system that I install.

If you have to ask if that's a check valve I will suggest you get a professional over there to fix the initial Problem. then show you how your recirc works.

Zman

Narrow it down.

First, do you have a water production problem or a cross connect problem?

Is the piping at the heater hot when you are having the problem? If so, you have a cross connect.

To eliminate the recirc loop as a culprit, turn off the circ and close the purge valve below it (you will have to find the handle or turn it 90 degrees with a wrench.)

If that is not the cause, keep looking. Sometime the best tool is just feeling the pipes around the house until you find something that doesn't make sense.

Carl

Xmytruck

Air

Is it possible that their is air in the system that is cause this issue? Would it benefiting I flushed the system?

Zman

Guessing...

Air would make sense if you had hot water after waiting for it.

Diagnose the problem, don't just guess.

Carl

Snowmelt

Here

Is the first thing you have to do seriously



On your remote you can see the exact temperature that's comming out of the machine.



You have to do that first to see if the machine is producing the temp that your asking for.



The secound thing you look for is if it doesn't keep up with temp is check the gas pressure, there been a job where I went & the gas pressure in the house was low, me and customer called the gas company, they came out the next day and found out that the main in the street comming to the home was rotted, they dug the street up I assume emergency repair with the city, then found the rotted pipe. I'm also going to assume they were smelling gas.

Xmytruck

Pump off

I have had the return off and the recirculate motor off for the last two day and no issue. I am going to assume it is the check value. Thanks for the help this board is awesome. Is this the check value ?

Charlie from wmass

yes

You found it! Look up spring check and use that to replace it. Yours is a swing check.

icesailor

Springing The Swing:

Me personally, I would be taking the cap off that check and looking for some debris inside. And whomever installed it, must be some form of rookie to have used street fittings to solder it together. You have to find a socket to fit the cap head. Whether a 8 Point or a 6 Point socket. You need to seriously back up the valve. You have to crank really hard on the cap. It will move 1 degree and you can get it off with your fingers. If you put it back, use generous amounts of carefully applied Teflon tape and paste. The best part of spring checks is that the spring breaks or debris gets behind the poppit. IPS Checks rule because you can put a union on them and unscrew them for cleaning, repair or replacements. The best part of soldering checks is that you can invertantly solder the check open or closed. And because that cap fits with a ground joint seal, you can easily solder the cap in place, permanently.

If memory serves me right (failing memory), check valves go in the return of circulation lines. Therefore, unless the picture is off by 90 degrees, the flow is down. Which way is the arrow on the valve facing? The direction of the flow or against the flow. If the flow is down and the arrow is up, the valve flapper is closed. If the arrow points down and the flow is down, the flapper is always open.

Best check that out. And put it in a horizontal position so gravity holds the check shut when the pump is off.

Recirculation pumping can be a hair puller to fix. You might need that hat that George Will wears on the Sunday Talk Shows.

RobG

Check

Ice, the picture is 90 degrees off. If you look at the boiler photo you can see the electrical box on the upper left.



Rob

Charlie from wmass

tired of swings

I gave up on trying to repair a swing check a long time ago.

icesailor

Check Fix:

They must have not been IPS checks with unions and the caps removed before installation for easy removal and repair.

hot_rod

check on discharge side

of the pump? it should be. Also a spring check with a cone, or soft seat is better.



Swing checks need a lot of flow to open fully, high Cv valves. They are prone to water hammer due to long travel distance, best for debris laden water like sump and sewage pumps.



Check valves SHOULD be sized by flow rate, not pipe size.



A swing check needs some back flow to shut tightly, a spring check is closed as soon as the pump stops. Consider a properly sized recirc pump with a built in check.