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they break it down fairly well here - full list of HIUs availableI'm just curious really. I did do a quick calculation based on 1500 apartments with the same heat loss and DHW requirements, plus a rough loss through pipework and it was like you say megawatts. I did have a quick Google on size of pipes required to carry this power but wasnt very successful. Like I said my experience is only on domestic properties, I would love to experience larger systems and definitely want to gain experience with commercial and industrial oil fired appliances. I'm not gas trained, oil is all we ever did.
Reply to the thread, titled "HIU - how do they work?" which is posted in Gaining Plumbing Experience on Plumbers Forums.
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