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New build hybrid heating system - badly configured?

Discussion in 'Plumbing and Central Heating' started by CSTB, 25 Aug 2021.

  1. CSTB

    CSTB

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    Hi,

    I've moved into a new build, built by CALA Homes. Overall, the house is great, but I'm not so sure about the heating system.

    Outside there's a Daikin air-source heat pump. In the garage there's a gas boiler. Upstairs there's a hot water storage tank.

    Concern 1: The heat pump only heats water for the radiators, and is set to only come on when the outside air temperature is above 11 degrees C. This seems strange to me, as at this outside temperature we're hardly ever going to have the central heating on.

    Concern 2: To maintain the warranty for the heat pump, we are required to have it serviced annually. This feels like it's going to be expensive, and will cost a lot more than the cost saving we'll get from the current heat pump configuration.

    Concern 3: Our combined gas/electricity bills are £180+ per month, which is about £50 more than the upper end of my anticipated spend.

    Concern 4: The gas boiler kicks in as soon as any hot water outlet is used. If I run the hot tap for 5 seconds, the boiler comes on to heat the water in the tank. In my last house the hot water was set to come on twice a day, and we never had a shortage of hot water. The developer told me that it was more efficient to have the boiler fire every time hot water is used. Again, this seems odd.

    I'm keen to get a professional opinion on this. Does it sound correct, or should I be going back to the developer to have it configured more efficiently?

    Many thanks,

    CSTB
     
  2. dilalio

    dilalio

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    Well it certainly doesn't sound right, from your description. However, it would be wise for you to have an engineer (who knows their way around heat pumps) to visit and appraise the installation.

    Too many organisations are speccing and fitting these incorrectly.

    See if there is a Heat Geek near to your area and get them in to assess what you have and if it will work.

    https://www.heatgeek.com/find-a-heat-geek/
     
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  4. jeff the gasman

    jeff the gasman

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    It’s all in the name of saving the planet but doing just the opposite.
     
  5. ScottishGasMan

    ScottishGasMan

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    If the boiler is coming on after 5 seconds of running water its either very wrong or its a combi boiler and the heatpump is only there for heating radiators.

    if its anything like a typical new build then the equipment will be there but nothing setup correctly so as suggested get a 3rd party who knows their onions about the heat pump and get them to look over the install and ensure its setup how it should be.

    FYI at 11 degrees outside your heating should be on providing a low grade heat nearly all the time, the reason they have it set this way is heat pump efficiency is dependent on outside temperature, it will work much more efficient when its a bit cold outside compared to less efficient when its very cold out outside.

    If the system was actually correctly designed with a heatpump in mind on a new build then you wouldnt need the gas boiler, but again on a new build I'd be amazed if it had been designed properly.

    have you any pics of the boiler and the water tank you could upload
     
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  7. picasso

    picasso

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    The water tank maybe a buffer vessel for the heat pump. as said probably a combi boiler , any chance of a few pics ?
     
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