Gas line for tankless hot water heater


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Old 04-20-18, 11:37 AM
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Gas line for tankless hot water heater

Hello,

My traditional gas water heater is approaching the end of its life. I want to replace it with a gas, tankless hot water heater. I think I understand how to route the water into the tank, but I wanted to ask about the gas line. Can I remove the pipes after the shut off valve and attach a flexible hose to the heater ? I’ve attached a picture. The tankless one would be mounted on the foundation wall behind the current tanked water heater.

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Last edited by PJmax; 04-20-18 at 08:23 PM. Reason: reoriented/enlarged pic
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Old 04-20-18, 03:29 PM
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The line going to the current water heater will have to be modified. The bottom tee will have to be turned so the gas line stayed tucked up against that duct. It will also need to be supported. The gas line will have to be run in black iron or a gas-tite material which will have to be cut to length.
That run will be too long just to throw on a flexible line. And the flex line would be exposed and susceptible to damage.
 
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Old 04-20-18, 03:48 PM
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A tankless water heater will likely need a larger gas line/volume of gas then a traditional water heater. Make sure you check the manufactures specs on the size of gas line required. It appears you also have another appliance off the same line that will have to be taken into account.
 
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Old 04-20-18, 05:05 PM
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Sounds good. I thought I could tackle this myself but gas lines scare the crap out of me. The other appliance is our basement furnace. I’ll let the pros handle his one.
 
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Old 04-20-18, 05:36 PM
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Also you will need a new , very expensive, vent pipe.
 
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Old 04-20-18, 05:50 PM
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why can't I just use my existing system? I have a concentric horizontal venting PVC pipe.
 
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Old 04-20-18, 08:32 PM
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My previous post was based on incorrect knowledge. You can use PVC.
 
 

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