Water heater drain pan pipe

[Qwertyjjj]

I have a 1.5" waste pipe that I have cut near flush with the floor.
The drain pan has one of these white connections with a gasket. It seems to take either a 1.5 or 1" pipe.
Firstly, when you tighten the gasket does it need silicone on the inside? Doesn't seem like the gasket would be water tight.
Secondly, how do I make the connection to the 1.5 floor waste whilst leaving an air gap? 1.5 to 3/4 reducer? I don't have much space to play with, maybe 3" from pan exit to floor drain.

 

[Jeff H Young]

the pans are pretty cheezy . the gasket may seal it may not silicone if you wish and test when dry. The pan is just a little bit of insurance often times the flex lines leak and spray to side with no or little water going in pan. if the water heater gets a huge leak pan overflows.
to connect to your dwv system requires a p trap and that trap needs to be primed. no airgap required . If floor drain is there just dump on floor over the grate

 

[Sponsor]

 

[Qwertyjjj]

The floor is wood, I don't really want to dump water over a grate as it could go anywhere. The p trap is already plumbed in under the floor

 

[Qwertyjjj]

So no air gap needed?
I can just glue in a 1.5 pipe with 90 degree and connect straight into the floor drain all sealed up?

 

[Jeff H Young]

how does floor drain recieve a prime? in other words floor drains need water to keep the trap from allowing sewer gas inside. if you seal pipe to floor drain then where does water go that gets on foor? You can cut part of grate and just run 90 into there. but no need to seal it or lose the use of floor drain

 

[Qwertyjjj]

I was thinking I would just pour water in the pan when it needs priming. Actually I was going to add a small layer of oil on top.
If no seal, then I'm back to what size to use. A 1.5 to 1.25 bushing then a 90 bend?

 

[Jeff H Young]

ok well you were never clear . in other words your floor drain sole purpose is as a receptor for the pan. I wouldnt plumb it that way.

 

[Qwertyjjj]

It's in a cupboard with no other water outlets. How else would you plumb it

 

[Jeff H Young]

I was thinking you might be able to just cut the grate and put the 90 down in there. there by still having use as a floor drain as well