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New tub shower install. Small issue.

djc2232djc2232 Posts: 113Member
Well not really a small issue but I had a standup shower removed and a tub shower combo installed. Everything works just fine but Ive noticed when just when the tub spout is on and into hot it will turn our tankless on and run. After a few seconds the water will be cold and the control panel on the tankless is showing a 11 error code. It is a Richmond tank and that is an issue with the gas flow. Odd right. Only happens with that, everything else in the house when running hot water is fine.

So i found out if i let the tub run on cold for a few seconds and build pressure then into the hot range, no issues. Doesnt seem to be causing any issue with the shower head.


  • Intplm.Intplm. Posts: 1,047Member
    The tub spout may have triggered the 11 error code and it might be a false flow code when transitioning from tub spout to shower head.
    This issue might be more accurately discussed if you can post some pictures here of your new shower tub combination, the shower valve and the water heater.
    With those pictures, we "might" be able to help.
  • djc2232djc2232 Posts: 113Member
    At this point it only throws that code 11 when initially turning on the tub spout all the way to hot. I just shut the water off and the tankless resets.

    Running on cold for a few seconds then onto hot, stays hot.
    Turn on all the way to hot and immediately pull plunger to activate shower head and stays hot.

    Its like there is low flow to the spout causing it to trip the tankless but it seems ive found the quirk to make it stay hot. Ill post some pics when i get home. Will be calling the place i had install it to get the guy back out here to take a look.

    Everything was fine prior to the install, and every other appliance that uses the tankless works just fine.
  • HVACNUTHVACNUT Posts: 2,824Member
    I'm not very experienced in tankless water heaters, nor do I want to be. But I'm aware of one manufacturer who's rep said to turn the hot 'On- Off- On'. I dont know if it's a common resolve but it worked
  • djc2232djc2232 Posts: 113Member
    Highly doubt it's an issue with the tankless. Everything worked fine up to the bathtub install. Only seems to be an issue when the tub faucet alone is opened to hot.
  • djc2232djc2232 Posts: 113Member
    Here's a few pics of the faucet valve and tankless. The tub and shower fixtures are all delta.
  • Leon82Leon82 Posts: 653Member
    edited June 2019
    The can it be trying to ramp up too fast before the flame is fully established? The faucet may have a higher flow rate than the old one.

    I would look for the viewport while you have someone open the faucet to see what the flame is doing
  • djc2232djc2232 Posts: 113Member
    That was what I had in mind. Something with the flow rate of the spout.

    But what puzzles me is if I let it run on just cold for a few seconds then on to hot, no issue. Or turn on to hot and have shower head on, no issue.

    Does seem like some sort of flow problem, but you'd think my well pump would keep up.

    Would not having a pressure tank be part of it?? It's on my list of things to do. Previous owner never had one put in when house was built.
  • djc2232djc2232 Posts: 113Member
    Now I can't seem to replicate the issue. It happened when I initially opened the faucet up then off again. Them it stayed hot. I tried to adjust the incoming water temp but that didn't really tell me anything since I couldn't get it to happen again.

    Seems like when it's been off for a long period of time it happens.
  • Leon82Leon82 Posts: 653Member
    The combustion chamber is probably still warm vs cold from a long period inactivity. Maybe it needs a small mixture adjustment
  • Jamie HallJamie Hall Posts: 12,100Member
    Ah now that's interesting...
    "Does seem like some sort of flow problem, but you'd think my well pump would keep up.

    Would not having a pressure tank be part of it?? It's on my list of things to do. Previous owner never had one put in when house was built.

    No pressure tank on a well pump system? You do like to live dangerously. First, check to see that you really don't have a pressure tank. Some shallow well jet pump designs have the pressure tank built into the pump. If you in fact do not have a pressure tank, get one on there to match the pump as soon as you can. Not having one is very very hard on the pump, particularly bigger submersibles, and can shorten their life a lot.

    Now -- how does that possibly tie in? Try this experiment: open the hot only very slowly, rather than quickly (as most of us do!). Does the problem persist? If not, I'd be looking at a momentary pressure drop in the system when you open the tap. With no tank, when you open the tap there is a time delay between when the pressure switch senses the pressure drop and when the pump starts and another until the pump builds any pressure. It's not long -- a few seconds -- and you might not notice it at the tap.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • Intplm.Intplm. Posts: 1,047Member
    Good pics. Thanks for sharing.

    I am not very familiar with the richmond brand tankless water heater. However I do believe that the water heater is reacting to the newly installed tub spouts flow rate. It's the only thing that has changed as you did have a shower and only a shower before this started.?? It seems to be the only thing that's new that makes the water heater show this code 11.

    Low flow on tankless water heaters will commonly make a tankless shut down. This most often can be a intermittent problem because water flow can fluctuate dramatically in a home for any number of reasons.

    In your case. Not having a pressure tank is a big issue. The pump to your home, as you probably know, turns on every time you turn water on. Without the pressure tank, the water heater will get fooled as to what pressure it is sensing and shut the water heater off "code 11". ??

    The pressure tank is important for many reasons. One is it helps to maintain a constant continued amount of flow to your system.

    You do not have that.

    May I suggest installing at a minimum, a Amtrol WX-202 tank or equivalent in your home.

    This will help maintain a constant flow of water. And once you do this, your water heater should stop showing code 11. This will also save you some money on your electric bill because of the contant short cycling of your pump. Your pump will live a longer life too.

    If you like. Call Richmonds' tech support line to see if they have any other suggestions.
    I'm pretty confident that they will suggest what I have.

    Good luck and PLEASE post back as to what you have done to correct this.

  • djc2232djc2232 Posts: 113Member
    No I don't believe there's on in the pump or well as the pressure switch kicks on and off quite frequently. Previous owner who built the house I don't believe had one installed. It's on my list to do. Hopefully soon.

    I talked with the guy who installed the shower and tub. He believes that because the tub spout is demanding more water flow this requiring the tankless to demand more gas to heat the amount of water. And there might lie the problem. Not enough gas flow to heat the water demand at the time thus tripping the code 11 gas flow problem.

    I have my gas company coming in to take a look at my propane regulators and possibly adjust tomorrow morning. Next step is to call richmond and possiblyy HVAC tech to take a look at the heater and adjust accordingly. And estimate the pressure tank install.
  • Intplm.Intplm. Posts: 1,047Member
    Usually when a pressure switch kicks on "quite frequently" as you say, that means that you either have a waterlogged storage / pressure tank or no pressure tank at all.
    This can make a flow sensor in your water heater shut the water heater off as a safety precaution. This type of problem is not uncommon with this type of water heater.
    So whenever you have inconsistent flow you run the risk of having inconsistent water heater function.

    Again. Try tech support. They may tell you the same thing but you never know.
  • djc2232djc2232 Posts: 113Member
    Service tech for my propane company came out and took a look at my gas regulators. All good to go. He turned the secondary one up just a tad but said that the pressures he was getting was just over what is required fore my home's application.

    He also tested the incoming gas pressure at the tankless heater when the tub faucet was running. The tankless is getting more than enough gas. So no issue there. He did say though that the gas pressure was ramping up and down. We took a look at the tankless and the manual for it and there isnt a way to adjust the gas flow within itself. I thought there would be? So at this point its pointing to just the fact that there is no pressure tank.

    Have my hvac/plumbing tech coming out Wednesday to give me an estimate. Installing a pressure tank seems easy enough but just dont have the time with work and a baby.
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