Gas Hot Water, 15mm (1/2 Inch) Gas Line

Hi guys,
I have a dicky continuous hot water system (Bosch H13), which worked well until the start of this winter. I need to replace the unit, but have come to realise that the gas line into it is 15mm (1/2 inch). Unfortunately, it looks like someone bodged it, as the unit requires a 20mm (3/4 inch) gas line in. Looking at all the continuous modern systems, it looks like they all require a 20mm line in, which is a big problem for us, as there is no access to the gas line itself (it is concreted through the floor below the unit, and runs the length of the house under sealed floorboards (with no meaningful access, apart from in one room). This means that replacing the gas pipe to the meter (at the front of the house) is all but out of the question. I live in a terrace house with other houses on both sides, so I can't run it on the outside walls.

Does anyone know of a hot water system that uses 15mm gas lines? It doesn't matter what kind of system, as long as I can get reliably hot water. The less gas usage the better obviously.

Is an electrical system an economic option?

Comments

  • Kelvinator uses ½ nom pipe.

    • Hi nocure, looking at the link you provided, every kelvinator unit appears to use 19mm gas pipes? That I assume is the 3/4 inch pipe isn't it?

      • Yep sorry , its 20mm gas in and 12mm water out.

  • +2

    You might want to give one of the manufacturers a call. Obviously yours was working with the smaller pipe. Perhaps the 20mm is just maximum size, and a reducer fitting at the connection is all that is required?

  • Need some more information.
    Is it working but not hot enough or dead?
    The previous winter did the unit perform satisfactory?

    You will find that all units specify 3/4" minimum but you can sometimes get away 1/2". If your problem is gas flow, it does not matter what unit you buy, heating water takes a certain amount of energy and if there is not enough gas flow the output temperature will be low.

  • Thanks guys, ended up getting a storage system fitted, worked out only a bit more, and has no problems with the smaller gas pipe

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