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    Navien 240 combi installed - I have concerns (51 Posts)

  • Tdubx Tdubx @ 12:04 AM
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    Navien 240 combi installed - I have concerns

    I just had a navien unit installed along with new pex piping and additional radiant in a back room. I've read a lot of posts that say I can run 2-3 showers with this unit. That's not what I am getting.

    At a set temp for domestic of 135, I can barely take a shower with the kitchen tap running.

    The radiant is not on at that time either. I don't have a recirc pump installed either.

    All pex lines, except for what's near the navien.

    A few questions:
    Curious, what people paid for professional installs?
    Am I missing something or setting somewhere?
    If I add a recirc line, will that shorten the life of the unit?
  • Snowmelt Snowmelt @ 12:11 AM
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    The 240 is there bigger unit
    There are a few issue on what's going on.
    Did you call navien yet?
    What's the water temp coming in?
    How many gpm do you have?
    Are you losing water pressure?
    Do you mix a lot of cold water, do you have it that high for dishwasher. If you have water temp down to 110 I bet it would still be hot.
  • Tdubx Tdubx @ 12:26 AM
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    No, I have not called them yet.
    Temp in is: 76
    Gpm: 2.4 with the tap on or off. Could it be the line into the house? It's only a 1/2"
    I lose pressure when I use more than one appliance or tap. I had the same issue as before, with my water boiler, but nothing like it is now.
    Yes I mix hot and cold. The guy who installed it has his water at 120. Maybe lower temp would be better?
  • heatpro02920 heatpro02920 @ 12:18 AM
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    We aren't allowed to talk price on this site...

    Did you call your contractor?

    Can you show us a picture of how its piped?

    Also get us the gpm reading on your shower nozzle..

    With a tankless system you want to be able to run your shower and faucets full hot with no cold mixing... Some systems and designs dont allow for this, but to me its ideal... 135 is too hot IMO, my tankless is set to 115 and 110 in the summer months...
  • Tdubx Tdubx @ 12:46 AM
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    I'll speak with my contractor tomorrow.

    Attached is a pic.

    Not sure about shower nozzle Gpm. It's a wand style. Waterpik brand.

    I changed my water to 120 for now.
  • Gordy Gordy @ 6:01 AM
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    1/2" waterline

    Is the problem. Are you sure about this?
  • HomeOwner1 HomeOwner1 @ 8:46 AM
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    We have 3/4 off well pump as water supply

    Our setup does indeed supply three showers with newer shower heads with the CH-240 unit we have running.

    Our supply line for water is much larger than yours though. We have a 3/4 supply line going directly into the unit.

    We also have our unit set to the well pump setting. Not sure if that is applicable on the newer units.

    Good Luck.
  • Snowmelt Snowmelt @ 9:45 AM
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    1/2 line

    I'm going with Gordy the 1/2 line is to small. In my house, the water line was 1/2 everywhere when we redid the kitchen that is when I. Had a chance to redo the water lines going in the wall. I I only wanted to do this once so I took 40 feet of 1" pipe then broke down to 3/4 then 1/2 at the fixture itself.
    Before when I was in shower I was in shower and flushed the toilet the shower loose pressure and became ice cold. Now I have shower 2 sinks and still flush toilet and get just a small pressure drop but no hot water loss.

    I don't like that set up, you don't need the pressure reducer and your suppose to use there own port for water going into the boiler. Also is the spiral vent getting air as water comes in or is it catching all the air every time it goes around the loop.
    There are 5 water ways 2 for heat 2 for domestic water and 1 for boiler feed which is 1/2".
    This post was edited by an admin on March 31, 2014 9:54 AM.
  • Tdubx Tdubx @ 10:11 AM
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    I keep re-reading your post but it's not clear to me what you've done. Can you re-explain.

    Are you saying, you ran 1" lines in your house, down to 3/4" then 1/2" to the fixtures? [That's a similar setup I have.]

    i dont get the same effect you do with the heat loss, mine's purely pressure drop.

    What do you mean by your 3rd paragraph "i don't like that setup..." it's not clear to me what you're saying there.
  • Tdubx Tdubx @ 10:04 AM
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    1/2" Line

    Yes i am sure about the 1/2" line. The houses in my area were all built that way and some of my neighbours have ungraded them from the main to a 3/4".
  • Snowmelt Snowmelt @ 10:11 AM
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    I would invest in 1 inch cooper and install that everywhere you can. Also get a 1 inch sediment filter (clear filter housing) the more one inch line you have in basement the better your water pressure would be. It's all about volume .
  • Tdubx Tdubx @ 10:15 AM
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    1" line

    I just had my lines re-done in the house. You're saying that PEX isnt good enough, and that the pressure from a 3/4"->1/2" sont suffice?

    I should also note, I am in a rancher house (1300sq ft) with radiant flooring that only touches 1000 sq ft of that area.
  • SWEI SWEI @ 10:20 AM
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    PEX is fine

    As long as it's sized and installed properly.  Underground, it's far better -- especially in acidic soil.  Watch out for the fittings and rings in that case.  ProPEX EP fittings and rings have higher flow and are immune to corrosion and dezincification.  You'll need PEX-A pipe to use them.
  • Tdubx Tdubx @ 10:08 AM
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    I'll check the unit for a "well pump" setting. Unfortunately there is nothing I can do with the 1/2" line unless I dig up a new run from the main on the street to my house; which I am almost tempted to do at this point to get my shower not to lose pressure.

    For me, I dont lose heat, just pressure, but after I run a tap, the shower barely stays on, but it does stay hot.

    The new pex that we ran in the house is 3/4" runs, down to 1/2" to the taps/appliances, so I doubt it's the new piping. Something tells me more and more it's the pressure from outside the house.

    Also, no one commented on my thoughts about a recirc pump shortening the life of the units. I read a post claiming that indeed it does just that since the it'll put more stress on the unit.
  • SWEI SWEI @ 10:14 AM
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    1/2" mains

    that I have seen were installed before WWII.  Run hard water through them for 60+ years and you get something more like a 3/8" line -- or worse.
  • Snowmelt Snowmelt @ 10:21 AM
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    Well tank

    What or should I say what size water tank do you have. Your well tank will be around 40 to 60 that will be the cut in and cut out. It's all about volume if I was using pex I would go 1-1/4 to the first few fixtures and to the water heater it sellf .

    For now I want you to just put all the hot water on and et the gpm off the remote.

    You can't really change water pressure coming in the house or at the tank, but what you can change is the volume of water after the water filter.
  • KC_Jones KC_Jones @ 10:17 AM
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    Just another homeowner here, but I will add the 1/2" is suspect.  I have 3/4" coming into my house, but the previous owner redid the whole inside with 1/2" everywhere.  Just having the 1/2" inside the house caused major pressure issues.  I had the scalding shower toilet flush issue.  I redid all the main "trunk" lines in 3/4" copper with 1/2" going to fixtures and it completely cured all the problems.  i can now pretty much open anything flush any toilet and not affect the other appliance (that a human can notice).  In my opinion 1/2" just isn't up to supply a whole house from my experience.
    Just another homeowner trying to find his way through.
  • Tdubx Tdubx @ 10:42 AM
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    Contractor and pressure.

    I just tested - 3 taps open on Hot only (kitchen faucet, bathroom faucet, and tub faucet) i was only getting 3GPM. I just had my contractor come over and he said for sure it's the service coming into the house. So looks like I may need to start doing some digging!

    Any thoughts on the recirc line shortening the life of these units?
  • icesailor icesailor @ 10:55 AM
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    Before you dig:

    Before you dig, check the service pressure like I told you in a previous post.
    If you have metered water, where is the meter? At the curb or at the house? Have it checked for flow. It can be "hanging" and not flowing as fast as it should. When the house was built, did they use 3/4" poly pipe? Is it 160/200# poly and did they use compression fittings or insert fittings? Some cheap installers back when used some galvanized steel insert fittings that if screwed into a brass  curb stop, will develop rust at the connection and slow the flow. Is there a curb stop just outside of where the water service enters the house? If the meter is at the property line and it is a distance away, is there a bib pressure drop from the meter location to inside the house? It will show that the curb stop needs to be replaced. Or you could have a big rock crushing the plastic/poly water service because someone was too lazy to hand backfill the trench to cover the pipe, Then finish with a machine. If it is rocky soil, it may not have clean sand under the pipe.
    If its a long run, really consider a booster pump.
  • icesailor icesailor @ 10:42 AM
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    Another take on your problem:

    Here's another take on your problem.
    First of all, that is a really nice professional installation. Be proud that you hired someone that knew what they is doing.
    You need to get something (or someone) to check the static (nothing running) and the flow (something running) at the water in the house. You have town supplied water. Piping houses with 1/2" copper is wrong, but if you go by the fixture unit valves in piping, it is OK, but you still need a minimum of a 3/4" water service where it may split and go 1/2" each to the water heater and the hot water, If the service entrance is 3/4" and reduces to the whole house from there, it is wrong. Put a pressure gauge device on the service entrance and measure the pressure, If it is under 40# static (not flowing), it will never work properly. If it drops below 30# when flowing, it will never work properly. If you have a single lever pressure balance shower valve, it will never work properly because the valve is constantly doing its job and protecting you by trying to balance the hot and cold water. If the Navien is set to 120 degrees, it probably can't over come the lack of hot water pressure and the volume of cold water.
    If you want, the easiest way to solve your pressure problem is to install a booster pump on the water service as it inters the house. You can buy stand alone units or make up your own. But it will raise the pressure and volume available in the system. Remember, when you raise the system pressure by sucking on a water service, you are theoretically increasing the street pressure by making the system use atmospheric pressure to push harder on YOUR system. Mother Nature HATES a vacuum.
    Where do you live?
  • Tdubx Tdubx @ 10:49 AM
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    Thanks Icesailor.I'm pretty sure you nailed it on its head here. My contractor is coming back later and putting my system to the pressure test. He said for sure it was the outside lines, as these homes I am in were build just post WWII and haven't had their services upgraded since.

    I live in the Vancouver, BC area, Canada. I'm at the bottom of the mountain so you figure my atmospheric pressure and gravity fed pressure would be good being so low. But that s not the case with my house. I remember speaking to my neighbours last year and they had to upgrade their services when re-doing their houses for upgrades/renos.

    And yes, I am super happy with the install. The guy who did it, has installed over 90 of these units in the Vancouver area and took his time with another friend and managed to install the unit, run new water lines in my house, new radiant lines and washer lines to my extension, add a gas bbq hookup outside, all in 2 days. Very happy.
  • icesailor icesailor @ 11:13 AM
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    You should be able to go to the water supplier and find out what you have for a service. Copper was cheap post WW ll, but if the builder had a surname that is often common in the northern British Isles, galvanized steel was cheaper and would be working fine when the deeds were signed over. If it is galvanized, there is definitely plaque problems with brass valves. Unless the pipe is galvanized wrought iron. If you have high dissolved iron in your water, definitely.
    If you replace the service, go with a minimum of 1" SDR/200# Poly. It will equal 3/4". I always used 1 1/4" with compression couplings to equal a 1" flow.
    If you get the water service fixed, you'll think you died and went to heaven.
    One good way to spot bad services without a gauge is to open a tap that is at the service entrance like a boiler drain, and open it up as wuickly as you can, note if the flow is high and then drops off to a steady, slow flow. Stop it, then repeat it. If the pressure goes back up and does it again, there is an obstruction. Sometimes, you can actually hear the water filling the pressure back. The slower the refill, the worse the obstruction.
    Where I worked, the water provider was a very old company started in the late 1800's.They had records going back to then. If you wanted to find out of an old house had a lead service, you could look in a 1890 service record and see the fittings they used to connect it.
  • Tdubx Tdubx @ 12:36 PM
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    I just spoke to the city and my water main was upgraded in 1989 to a 3/4" line from the city side. At that time, the pressure was noted as being 110# at the main. So I basically need to run new lines from the main to the house. Sounds like that is where my pressure problem is stemming from!
  • Paul48 Paul48 @ 1:20 PM
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    Not Yet

    As said....Check the pressure in the house. Is there a PRV on the supply where it enters the home from the street? With that kind of pressure at the main, you should not be having the problems you're having.
  • Tdubx Tdubx @ 1:32 PM
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    Yes there is a PRV that is on the line just before it enters the house. I was told to change that if I did my water lines from the main to the house.
  • Gordy Gordy @ 1:20 PM
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    Ditch the 1/2"

    You will never have decent flow to multiple fixture simultaneously until you increase your line size from the main. I don't care how much city pressure you have. I would size 1" since you will be doing it.
  • Paul48 Paul48 @ 1:37 PM
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    I guess 22 or 23 GPM to the house would not be enough.
  • Tdubx Tdubx @ 1:46 PM
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    Acceptable GPM

    What would be the acceptable GPM. I already know I'm low, but what's a good number to get. Maybe i can get away by just changing my PRV instead of the entire run?
  • Paul48 Paul48 @ 1:57 PM
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    I sound like a kid- OMG

    Maybe the PRV is adjusted to 20 psi? Buy a $20 sillcock gauge. Make sure the sillcocks are piped after the PRV, and CHECK  THE  PRESSURE.
  • Snowmelt Snowmelt @ 4:35 PM
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    You didn't give us any pressure yet, go to the plumbing supply house and buy a water pressure guage that you can hook up to your hose bibs or faucets. Then tell us what it is when running then after running pressure is not volume so giving us g.p.m. Doesn't tell us what pressure is coming in home .

    Here is what may be happening, your in the shower and you have 1/2 pex and someone runs another fixture, then your stealing the water in the shower line to feed other fixture. If you increase pipe size you will increase volume of water in line and pressure (running pressure) won't drop as much.

    Your boiler
    Look at bottom of boiler is there 2 one inch tappings for boiler water, 2 3/4 tappings for domestic water and 1 1/2 feed all the way to right for boiler feed.
    Then there is 1 3/4 tapping for gas and 1 1/2 tapping for condensation (ran in PVC)
    This post was edited by an admin on March 31, 2014 4:40 PM.
  • icesailor icesailor @ 4:51 PM
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    1/2" piping:

    It is perfectly acceptable to pipe a house 3/4" and 1/2" copper and the house must have a 3/4" service into the house. And then, a 3/4" pressure reducing valve. You split the copper into 2 halves, one going for the cold and the other feeding the water heater. That way, you have equal hot and cold water pressure and volume on both sides of the shower valve. Good money is on a bad PRV. If you have 110# at the street, and the house isn't on a hill, 100' above the street, 110# is enough to blow a glass out of your hand.
    We always talk about the need for digital combustion analysis on heating equipment. You need pressure gauges to tell you what's up. You need one on the street side and the house side of the PRV. To see if the street side is 100#+, and stays there when t runs, or drops appreciably while running, and see that the house side is adequate for the height of the house and how much it drops.
    For smelly toads sake, all the hot shot plumbers are now running home run 1/2" PEX CTS tube in all the new and old houses. 1/2" CTS PEX has a smaller ID tha 1/2" Copper Tube.
  • Tdubx Tdubx @ 5:09 PM
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    Snowmelt - correct about the boiler setup and water. 1/2" lines go to a 3/4" then to a 1". Domestic is PEX all around the house at 3/4" then small runs from the attic to the fixtures themselves. My contractor said the low pressure could also be from rust and debris in the lines that may be caught up in the filter. We have yet to investigate that either. I have had issues with sediment and other rust in my copper pipes and has to constantly clean out my kitchen and bathroom faucets to get pressure back and clean them out.

    The house isnt on a hill, in fact it's at the bottom of one. That pressure test was done back in 1989, but even still, the fire hydrant across the street, from what I'm told, is holding a pressure of 100#. So I too suspect a faulty PRV since the valve and copper has rust and has been problematic before. i dont plan on digging anymore than i need to. My PRV and the line into the house is easy enough to change so i plan on doing that first before any digging.

    Yes, toads are everywhere Icesailor.
  • icesailor icesailor @ 6:21 PM
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    If the line coming through the foundation is copper, and what the water supply company replaced was connected to copper (they should know), you do NOT have a plugged up or obstructed copper water service. Unless it is common in your locality, it just doesn't happen and you're not the one. They make inline filters. CUNO makes an excellent one with high flow and replaceable cartridges. I would install them on new well water systems because one driller where I worked, never developed his wells to get all the fine sand and drill mud out of the casing. You sound like you have an iron issue. Like it is precipitating out of suspension and into a solid. There should be a small screw in filter on the water inlet to the water heater part of your Navien. I'm not familiar with Navien's, but all the others I have worked on, have this filter. Look for it. Pull it out and check to see of it is plugged up. Sometimes, you have to blow it with air. But if it slows down the water flow, it turns down the gas flow so as not to overheat the unit.
    As this string goes on, I personally think that you have a service issue and not a mechanical issue. I promise you that if that Pressure Reducing valve was set at 75#, and you got in the shower, it would hurt a lot. Like most people can't take the pressure. Even at 60#, it still hurts in the second floor. And the first floor, you'd be backing off the pressure.
    Check out the filter I am posting (I think). I always connect them up with McDonald MPT X CTS compression adapters for underground use with the big clamp and stainless steel bolt to keep it from blowing off.
    This one:
    This post was edited by an admin on March 31, 2014 6:33 PM.
  • Gordy Gordy @ 6:30 PM
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    psi, and 1/2" line, and volume.

    Cmon really fellas You need the volume to go with the pressure. Only get so much through 1/2" pipe.

    Paul where are you getting that high of GPM in 1/2" pipe of any type?
  • Snowmelt Snowmelt @ 7:34 PM
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    Pressure reducer

    Where is the pressure reducer on the boiler, you don't needed one

    For your domestic we don't know what the pressure us yet
  • Paul48 Paul48 @ 7:41 PM
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    Not 1/2"

    He's got 3/4" from the main at 100+ psi. The drastic drop in gpm with multiple fixtures can't be attributable to that. I believe he said he had 3/4" with 1/2" to the fixtures. I don't know for sure, but there is the possibility that when he had a tank type water heater, turning the PRV down may have been someones answer to a dripping relief valve, in the absence of an expansion tank. Just a W.A.G.
  • Snowmelt Snowmelt @ 8:03 PM
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    I think he had 3/4 pex we don't know how many gpm he is using could very well be that. Still have to get a gauge and check water pressure.
  • Paul48 Paul48 @ 8:22 PM
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    Long Post

    "I just spoke to the city and my water main was upgraded in 1989 to a 3/4" line from the city side".
  • Paul48 Paul48 @ 8:23 PM
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    Long Post

    "I just spoke to the city and my water main was upgraded in 1989 to a 3/4" line from the city side".
  • Gordy Gordy @ 8:13 PM
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    1/2" to house

    1/2" from water meter feeding house either way the distribution line needs up sized to 3/4" min.

    Im confused. By the op Around here when the city recons a street with new sewer, and water new water lines get run to the house. So maybe I'm misunderstanding when he said he had to dig up the line a few posts back.
    This post was edited by an admin on March 31, 2014 8:21 PM.
  • Paul48 Paul48 @ 8:25 PM
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    Long Post

    "The new pex that we ran in the house is 3/4" runs, down to 1/2" to the taps/appliances, so I doubt it's the new piping. Something tells me more and more it's the pressure from outside the house".
  • Tdubx Tdubx @ 8:54 PM
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    Here's an update, i didnt get the pressure valve tester (yet), my plumber is going to get me one and i'll test what I currently have to the house this weekend. As for the water lines. The water main sits on the city's side, so it was their responsibility to change and upgrade it. At that time (1989) they did a pressure test and concluded 110# at the main.

    More recently, i went around the house to check my PRV and noticed that I actually have a 3/4" line from the city side to my PRV, then a 1/2" into the house, and ultimately connecting to the navien. So, my plan is to upgrade the 1/2" line that site just outside my house, I wont have to dig up and concrete or foundation since the line is actually run on the outside of the house in contained area, so this should be relatively easy to upgrade. At that time i'll re-test and see what I have for pressure. Everything seems to lead to the 1/2" line coming into the house and/or the PRV.

    And yes, in the house I have 3/4" to 1/2" PEX to the fixtures.
  • Gordy Gordy @ 9:28 PM
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    Thank you

    I knew ther was a 1/2" bottle neck in there somewhere from the street to inside the house.

    Still a little confused when you say 1/2" runs off the prv to the Navien. So the cold side is 1/2" to Navien, and all cold side on fixtures. So when you ran new 3/4" pex you tapped into the 1/2" for your distribution lines of 3/4, and then back down to 1/2" to the fixtures?
    This post was edited by an admin on March 31, 2014 9:32 PM.
  • icesailor icesailor @ 10:06 PM
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    Getting confusing:

    This is getting confusing.
    First of all, no matter what size water pipe you have going to a fixture (except shower valves and tub valves), they all reduce down to 1/4" ID Tubing. The current El Cheapo PB spaghetti risers are even smaller. Even if you ran 2" copper to under the sink, the fixture is still fed by 1/4" ID tubing.
    Although it is nice to have 1" run all over, it is commonly accepted installation practice to use a majority of 1/2" tube/piping in residential installs. Its nice to go bigger if you can afford it. Its nice to be competitive for jobs.
    Massachusetts is as middle of the road as you can get. The minimum water service size is 3/4", even if it only serves a toilet. I don't know how cold it gets where this house is but if Canada, I'll bet the service is 4' down. Not a recital of the Earth Guitar Band. As far as checking the pressure, go to your local supply house and pick up a 0-160# 1/4" Bottom gauge and a 1/2" X 1/4" Reducing coupling or ell and a 1/2" boiler drain. Plus a washing machine hose. Connect it to any boiler drain you can find and turn it in. That will be the pressure. Let it flow, check the pressure. Its not expensive science.
    Before you go nuts and start re-piping the house, check the PRV. It isn't working properly.
    My Florida place is all 1/2" copper with a 3/4" copper service. The city maintains at least 60#. The pressure doesn't go up or down. But because of El Cheapo Moen 1982 Moen single lever Non-Pressure balance valves, if anyone turns on a faucet, you immediately feel it in the shower. Like I said in an earlier post, the Pipe Du Jour is now, 1/2" PEX, with home runs from a fixture to a manifold. Plumbing, heat and gas. 1/2" piping is the rule of the day.
  • Snowmelt Snowmelt @ 10:28 PM
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    I'm going to have to disagree
    Take your 1/2 pex and take my 1 inch copper
    Open 4 fixtures in your home
    I know what will happen but I want you to tell me?
  • Tdubx Tdubx @ 11:35 AM
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    ICESAilor: Your thought process... the same as my plumbers too. He said we can run 3/4" in the whole house, then 1/2" down to each fixture It's all about volume, which will give you the right pressure.

    If we are already getting low volume from a 3/4" line from the city side to our final run of a 1/2" line to the Navien, then we've already lost volume, resulting in lower pressure. No matter what we do inside the house, won't help.

    My area doesn't get colder than 30F (or minus 10C) and my lines run down about 2ft, not 4ft so I can access them quite easily.
    This post was edited by an admin on April 1, 2014 11:35 AM.
  • Tdubx Tdubx @ 11:38 AM
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    Let me explain..

    From the street the lines are 3/4", then on the outside of the house (before the PRV) they change to 1/2". At that point the 1/2" line goes into the PRV, then inside the house. So, ultimately, the 1/2" gets connected to the Navien (as per my picture above).

    What I meant was, the new lines from the Navien were all 3/4" (those are all in the attic), then the runs down to each fixture are 1/2" (those are smaller runs of no more than 10ft).

    Hope that makes sense.
  • Snowmelt Snowmelt @ 9:40 PM
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    In the mean time

    Are you going to do the work yourself, I suggest you look up static and dynamic pressure.

    Also whatever you replace use one inch copper or 1-1/4 pex you want volume
  • Gordy Gordy @ 10:55 PM
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    So if your 3/4" line

    Has a 1/4" kink in it from the street to the house that does not make a difference?

    This could go everywhere. My point is if your using multiple fixture simultaneously you need volume to the fixtures the closer to the fixture you reduce down the better. It would drive me nuts to have to use one fixture at a time or there will be war crystal from the shower stall.
  • RobG RobG @ 11:49 AM
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    Don't forget

    Don't forget the pressure drop through the Navien. The 1/2" main and the pressure drop through the heat exchanger is a recipe for dissatisfaction.

  • HDE HDE @ 6:25 PM
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    Not on a combi

    Domestic flow is through a plate heat exchanger so, pressure drop is minimal, maybe 5 psi at 5 GPM?
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