No hot water Remeha boiler

Hello!

I've been using tado conntected with my Remeha boiler about 3-4 months and very happy with it. I've installed Tado myself.

Then the problem starts..

Occasionally there's no hot water when I want to take a shower. The boiler shows an error message. On the app, the hot water is on. I have to turn the boiler off and on in order to get hot water....

Has anyone experienced a similar issue? My boiler maintenance guy said that it's a frequent issue for tado & Remeha boiler user. and they suggested me to install "by-pass", which costs 250 euro..!


I wish there's a cheaper solution!!


Look forward to hearing your wisdom...


Thanks,

Ohyoon

Answers

  • A bypass valve allows hot water to circulate through the boiler when there is too much resistance in the pipework. The resistance increases when TRVs close, causing the flow of water to slow or even stop. This causes the heat exchanger to overheat and the boiler locks out until it is reset.

    If fitted you may have too many TRVs, or your motorised valves are closing prematurely. Your heating engineer is right to suggest a bypass is fitted, and a lot of boiler manufacturers now mandate the fitting to protect their boilers from damage.

  • gary333
    gary333 ✭✭✭

    Do you have the model of boiler, and the error code by any chance?

    It's a good idea to have a bypass valve fitted however most modern combis have these already. I would say the cheapest option is to ensure you have one (or maybe a couple) of smaller radiators that do not have TRV's fitted. This will allow the water to pump around.

    If it's built in to the boiler, did the heating person check it hasn't been wound right down (i.e. not setup correctly?)

  • ohyoonk
    ohyoonk
    edited March 2021

    Thanks both! What's TRV? Does it refers to Tado thermostat attached to each radiator? My house 80m2 and we have one floor heating (has one tado valve) and 2 radiators. And all have Tado products.

    If I understand correctly, The problem may occur there's too much hot water available but there's no way to go out because all radiators are closed.

    My boiler model is installed in 2019, Remeha Tzerra Ace.

    The error codes are H.01.05 and H.01.14

    In my Tado app the hot water temperature sets as 55 degree, perhaps lower the temperature can help?

  • TRV = Thermostatic Radiator Valve.

    The problem occurs because the heat exchanger needs a constant flow of water. When the water stops flowing the heat exchanger becomes a kettle and the water boils, leading to increased pressure. Lowering the temperature will not help. The only solution is to keep the water circulating. This means removing one of the radiator valves are fitting a bypass valve.

    This is what the two error codes mean:

    H.01 - .05

    Temporary Fault - Maximum difference between the flow and return temperature exceeded. Non-existent or insufficient circulation. Sensor error.


    H.01 - .14

    Temporary Fault - Maximum flow temperature value exceeded. Non-existent or insufficient circulation. Non-existent or insufficient circulation.

  • Thanks! I understand. The error codes indeed indicate the issue. Then what happens in summertime, when all radiators are closed....

    I assume that Tado triggers this problem. Is it true?

  • In the summertime you should not have a problem when hot water is only required for shower/taps. This type of problem normally only affects heating circuits. The heating engineer who visited your home will give the best advice.

    Any brand of smart valve is likely to trigger this issue. Not a specific problem with Tado.

  • In the summertime when you are only using hot water for shower/taps there should not be a problem. This type of error normally only affects the heating circuit.

    Tado is triggering the problem, but the source of the error is the absence of the bypass valve. Changing the brand of smart thermostat is not going to the problem.

  • Hi there,

    I had the same problem with my new cv Remeha Tzera Ace, there was no bypass for water to circulate after the cv goes off. So I left one radiator always open. And it sims to me that my old cv worked better with tado, as I had all valves closed and then the water would still circulate somehow.

    But I am still not sure if the tado and Remeha are communicating properly as I can’t control my hot water for taps in tado. With my old cv I could tern off and on hot water for taps/shower with the new cv I can’t.

    Suggestions?

    Kind regards,
    Vova
  • kkupe
    kkupe
    edited December 2021
    Hello
    I replaced my old boiler with Remeha Tzerra Ace and have the same issues.
    I think I had it with the old boiler too, but I thought it has some other hardware problem (like sensor error) and is not worth to repair it, so just replaced with a new one.

    I also realized that the bar pressure gets low suddenly rarely. I would expect that it only changes 0.2-0.3 but it went from 2.4 to 1.5 today
    I turned on one room with tado and the bar increased to 2.3 in one minute.

    I contacted the installer and still waiting for a reply. Btw I have 6 TRV radiators in total, only the one in hallway has no tado (it has a manual TRV). I think I have to have a bypass valve or convert the hallway to a regular non-thermostatic valve but it is harder since a plumber should replace it and drain the system etc.

    Would replacing the manual TRV in the hallway with tado fix the problem?

    Can the bar pressure problem be related to that?

    (There is no any room that has tado room thermostat but no tado smart radiator thermostat.)

    Thank you in advance.
  • I have the same problem with the Remeha Avanta. This weekend i have installed TVR's on all my radiators and one Thermostate for 2 radiators in the living room and this morning I didn't have warm water from the tap in the bathroom and pressure in CV systems was low, 1.2bar

    The trouble sign on the Remeha E2 E10 is refering to low water pressure so i fill the Remeha up with water till 2.0 bar. Didn't help, still having the same problem

    after discussing tjis with the Remeha installer he told me that Remaha always need a little bit of flow of the water between the in and out going water lines. After removing one Tado TRV (the heater fitting goes open) and resetting the Remeha the problem was solved. The Installer adviced me to use one manual TRV and leave it open for a bit or install a Bypass.

    I find it strange that this problem that seems to be known for longer time by Tado is not mentioned in all the technical and installation manual. Now i have 1 Tado TRV that I cannot use anymore :-(

    Isn't there another solution from Tado? opening 1 or 2 TRV for a short time in a time frame to get the water circulation normal so the Remeha system thinks it is OK

    Regards Edjo

  • I have the same issue with both error codes. I have a radiator without a normal TVR, as I already removed the Tado one. I have a bypass installed, but still I have these error codes. The WAF is currently at 0% as cold water only seems to happen when she takes a shower........