Closed Crawl, Radon, DHW Replacement, Sump, etc…..
I recently bought a house that is in general working order but needs some upgrades.
首先，问题：
– The current 30 gal DHW tank is probably on its last legs. It is located in the vented crawlspace and is not installed properly; it is sunk in the ground ~2 ft and has incomplete retainment surrounding it (see picture). This is the low point in the crawl and there is no sump pump currently installed.
- 房屋的ra子测试失败了，将需要缓解。
- 炉子位于爬行空间中，没有管道燃烧空气。
This is the work I am considering:
– Ideally I would like to replace the DHW tank with a closed combustion tankless unit. The cost may be prohibitive if the main gas line is too small, so I may need to go with a closed-combustion storage tank unit. The benefit of going tankless would be that I could use the existing hole that the tank sits in now as a sump. Additionally, bc it’s in the crawl, installing a bigger tank may be difficult if possible at all.
- 在主机上安装带有关闭阀的污水坑/泵或泄漏传感器。
- 向炉子提供高/低管燃烧空气。此时带有封闭燃烧炉的更换不在预算中，而该单位18岁时的工作状况很好。
– Install a passive radon mitigation system w/ perforated pipe per EPA specs. Vent using the current DHW exhaust chase but re-line with PVC. This assumes the closed combustion DHW can be exhausted through the wall, but I am not certain if that would work or is allowed. I plan to monitor the radon in the house and the system could be toggled to an active mitigation system by depressurizing under the poly via an exhaust fan installed in the attic.
- 密封通风孔，并携带缓解墙壁上墙壁的多层衬里到第一行砖（请参阅图片），然后用2英寸的XPS或Fire fire firet tater Polyiso将墙壁绝缘my water lines and mechanical equipment will no longer be ‘outside’.
DHW需要更换，但我觉得我需要一次做所有事情。我要在这里发布，以了解每个人在我建议的解决方案上的想法。另外，我计划自己做很多工作，因此，如果有人发现任何重要的代码问题/红色范围，请告诉我。这所房子在丹佛使用2006 I代码。期待你的回复！谢谢。
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Replies
您的处方是明智而全面的。
I don't generally recommend demand water heaters because of their expense, over-sized burners, and finickyness to hard water and low water flows - but in your case it may make sense. However, I see no evidence in your picture of water damage to the water heater so I'm wondering whether your concern is about ground water or a bursting pipe.
You might consider replacing the existing tank with an Energy Star power-vented tank and placing it in a more water-tight base, such as a concrete well tile with poured bottom. If there is a better location within the crawlspace, it's easy enough to relocate the plumbing.
Don't forget to air seal and insulate the rim joist area.
Thanks Robert. My concern is about a bursting pipe, there is no evidence of groundwater issues. If a pipe failed today it would be messy but may be OK bc the floor is dirt, once the poly gets laid out a leak becomes a much bigger deal I think.
From your picture, looks like you have black iron pipe for your gas line which would lead me to believe you have a 7" water column gas system. We typically need to run a higher pressure system for the tankless water heaters but can run 2 psi system and leave the rest of the house on the original low pressure system. The gas company will happily come switch out their meter for the higher pressure and you put a regulator at the meter to divide the two systems. Not a big deal at all, we do it all the time but I would leave this to the professionals. Everything else should be fine for a DIY if you pay attention to the details.
如果您关闭爬行空间，则必须提供某种通风。您的选择是；仅提供，仅排气或平衡系统。对于现有的爬网改造，我总是建议使用一个仅排气系统（连续运行的松下风扇） - 这也可能有助于您的rad rad系统。尽管稀释并不是高水平ra的绝佳解决方案，但人们在低水平方面取得了成功。