Which option is better for a steam oven drain?

[Rossn]

We are looking to add a small combi steam oven to our kitchen during remodel, and found a gaggenau highly discounted. Install manual calls for min 1.6 ID drain, which says to me 1.5" abs min.

Two options for running the drain:
1) extend a drain for a bar sink, which is downstairs... not the easiest, but possible. It is a 1-1/2" drain leading to a 3", and only the bar sink on it.
2) run drain from kitchen sink, through 8' of kitchen cabinets. That 2" ABS currently has planned 1 kitchen sink with dishwasher and one prep sink. Looks like IRC says 6 DFU's for a 2" drain, and a kitchen sink + dishwasher group = 2. I'm assuming a prep sink = 1, so we should be good.

Is there a preferred approach?

Can the ABS tee off the kitchen sink drain and be run through the cabinets (exterior load bearing wall behind cabinets is only 2x4 construction), after they are installed? It would ultimately run to a 'broom cabinet' next to the oven, and have a trap and air gap.

While I think I can get a mfg extension for this particular oven's drain, it seems like other mfg's have shorter hoses, so I would want to plan a permanent solution.

Thanks!!

EDIT: FWIW, Miele gives an exit temp of 160F, whereas Gaggenau does not... but both have about a 10' hose that they say should not be shortened, so I believe they are targeting the same cooling.

 

[Breplum]

To drain that type of appliance, it needs to go into a trap-protected, air-gapped drain receptor. We often use a simple p-trap and a pipe increaser from 2" to 3". However, a 2" trap arm can only run 5', not 8' unless you vent it at the 5' point.

 

[Sponsor]

 

[Rossn]

To drain that type of appliance, it needs to go into a trap-protected, air-gapped drain receptor. We often use a simple p-trap and a pipe increaser from 2" to 3". However, a 2" trap arm can only run 5', not 8' unless you vent it at the 5' point.

Thanks so much for your response.

It could be vented at 5', though I was thinking more about running a lateral from the main sink to the 'broom' cabinet next to the oven and having the trap and standpipe there, with an AAV... ?

If I was to run the mfg drain tubing (with extension) all the way back to the kitchen sink cabinet - how would I maintain the air gap at the kitchen sink stack, while also ensuring if there was a clog downstream, it did not overflow in the cabinet? This is probably rudimentary, but I haven't done it previously and was thinking a normal air gap probably doesn't apply here.

 

[John Gayewski]

I'm not sure what this appliance is. Does it drain steam condensate?

 

[Breplum]

For sure a clog inside a cabinet at the kitchen sink main drain would be a mess.
Air gap rules always applies. We never are allowed to connect directly to a drainage pipe without it due to clear health hazard.

 

[Rossn]

I'm not sure what this appliance is. Does it drain steam condensate?

Yes. It is an oven with a steam feature. The mfg requires the 10' of included flexible drain tubing, which they instruct should not be shortened. I believe that is so they can get the temperature to drop sufficiently to put it into ABS. I learned today that Gaggeneau is made by Bosch. I think the only other residential steam oven with built in drain is the Miele, and they mention not shortening their 10' drain tubing, and that it discharges at 160F

 

[Rossn]

For sure a clog inside a cabinet at the kitchen sink main drain would be a mess.
Air gap rules always applies. We never are allowed to connect directly to a drainage pipe without it due to clear health hazard.

Thanks. All that makes sense, and would definitely plan for an air gap. I figured out today how I could route a 1-1/2" drain off the bar... it is tight (there are 2 mini split line sets and a 250 SER cable within about a 6x6x6 area), but it will go. So, that will allow me to have a separate stand pipe of height coming off a different section of the main drain, and that will minimize the risk of a backup, as well as leave the flexibility to plumb in a second dishwasher, if ever desired. I think this will be the best approach.

Do you know how many DFU's a prep sink is considered?

 

[Breplum]

"Bar" sink is 1 DFU, Kitchen sink is 2.
Can you just dump the excess steam condensate to the outside?

 

[Rossn]

Ok, so a prep sink is considered a kitchen sink (in my mind, there is much less water going in that sink, which is why I wondered). I could dump it outside, but being under remodel, would probably prefer to send it down a drain if possible.