Do you really need a pipe out for potential harmful gas for pump
Do you really need a pipe out for potential harmful gas for pump?

Not in an otherwise properly plumbed system, but you should consider adding a stand pipe to help protect yourself from an overflow during a system failure.



As long as there's a check valve on the discharge pipe that would mean there's no chance for sewer gas, just moldy bucket smell after a while, possibly. With a sink also tapped into it you might want to pipe it to your stack, but with just a washing machine and all the soap going through it, it should be fine.

They're talking about an air admittance valve, which you don't need necessarily but you could add one if the bucket starts to smell. Here's a picture showing a piece of pipe open to the air, doing absolutely nothing as far as odor mitigation, which is fine because the system has a check valve and probably doesn't see much kitchen waste or the like.

That additional length of vent pipe would however allow you to fill the sink without flooding the floor in the event of a pump failure, before you realized it had. It also additionally increases the holding capacity of the pump to the size of the sink. So if you have a similar setup and you do install an AAV, you might as well put a length of pipe on it too. Also, should the check valve ever fail, having it elbowed into the sink would help prevent more catastrophes, and unless it at least has a stand pipe you won't get that extra holding capacity.



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