Continuous gas hot water addition to existing solar storage

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• Plumbers Quote Request #274281

Philip requested 3 quotes from Plumbers in Yarra Glen

  I'm considering getting a continuous gas water heater and putting it on the outlet of our existing electric-boosted solar hot water tank so that we don't have to use electric boosting anymore.

We will then be able to turn the gas unit on when necessary to add heat to any solar heated water we use on days when there hasn't been enough sun to get it hot enough (or if there have been too many showers and loads of washing). Currently we use electric boosting but it's getting very expensive to use.

We don't need a big unit - 21 l/minute will do because we don't want to make a habit of relying on it all the time.

Important points:
- we have a 20 mm copper gas line from the meter to the central heating, a distance of about 15 metres.
- our central heating uses 105 MJ/hr
- we have a gas cooktop on a 1/2 inch pipe branching off the 20 mm pipe, it would use about 60 MJ/hr if all burners were running but they rarely do.
- the water heater we're considering would use 170 MJ/hr (Bosch Professional)
- our gas meter seems only capable of delivering 269 MJ/hr if I have read it properly (7 cubic metres per hour with 38.53 MJ/cubic metre), but our gas is at high enough pressure to run the central heating through that 20 mm pipe (which was originally installed for LP gas)

We would probably get a Bosch heater because I can buy one at a special discount day this weekend, so that wouldn't have to be included in the quote.

There is space for the gas unit near the hot water tank and central heating - should be enough clearance to satisfy regulations about ignition sources, windows, vents etc. A powerpoint is available too.

I'd just like to know whether a gas line and/or meter upgrade might be necessary and therefore what the total cost of all the installation would be. If it's too expensive to upgrade the gas supply, it won't be worth installing a gas unit.