Testing trap primers

[randynavarro]

I've asked before but wanted to see if there are any new thoughts or input from some of the newer members here.

Anybody have any good methods or even know if a test method exists for knowing if a trap primer is functional?

[Brandon Whitmore]

How about trying to suck the trap dry with a big syringe with a tube attached?

[randynavarro]

Hmmm. I'm going to have to think about that. . . .

[Jim Katen]

I've asked before but wanted to see if there are any new thoughts or input from some of the newer members here.

Anybody have any good methods or even know if a test method exists for knowing if a trap primer is functional?

Simple answer: look in the trap. If it's dry, the primer isn't working. If it's wet, the primer probably is working.

If you really want to verify operation of the primer, activate it. If it's a pressure-drop type primer (by far the most common out there), run water at the fixture associated with it and watch for a discharge of water into the trap.

If it's a continuous-drip type primer, likewise, run a bunch of water through it's line and watch it drip, drip, drip.

There are also some that are part of a toilet's flush mechanism. I have two of these in my house. You can just remove the toilet tank lid, and watch the water as it's directed into the trap primer tube. As long as little tube doesn't overflow, you know it's working.

Another thing to consider: I did a 1-year inspection of a new multi-family building a few months ago. It had terrible problems with sewer smells in the laundry room. The floor drain trap was bone dry, but the trap primer was working perfectly. It turns out that no one in the building had used the laundry sink in months. Since the trap primer only worked when someone ran water in the laundry sink, there might as well have not been a primer at all. The building owner was content to tell his maintenance staff to run water in the laundry sink now & then -- problem solved. Another alternative for him might have been this gizmo:

http://www.asse-plumbing.org/Articles/N ... 20Seal.pdf

- Jim Katen, Oregon

[Marc]

Had to google 'gas trap primer'. Just wondering if I'm the only forum member that didn't know what that was. Never seen one.

Marc

[Stephen D. Gazo]

No Marc, I googled it as well. I only read a little bit but am certain I have never seen or heard of it...until

[Greg Booth]

I have only seen them in hospital facilities--never observed in a residential setting.

[Jim Katen]

I have only seen them in hospital facilities--never observed in a residential setting.

Wow, I'm shocked. Even 100-year old houses around here have them (never still in working order, of course).

For those of you who've never seen them, how do your floor drain traps keep from drying out?

OK, I can see why Marc might never have seen one; in LA they probably don't have basements or floor drains. But in NY & Ontario?

[Bill Kibbel]

Never, ever in residential. I only see them in commercial and industrial buildings.

For those of you who've never seen them, how do your floor drain traps keep from drying out?

What traps? The only floor drains are in homes on a slope and they drain to daylight, not the sanitary sewer. Almost every other home has a sump pump system.

[Ben H]

Had to google 'gas trap primer'. Just wondering if I'm the only forum member that didn't know what that was. Never seen one.

Marc

You are not alone sir.

[Stephen D. Gazo]

My mom had the washing machine in the basement beside the drain, she kept it primed. My last house had the AC and Air Exchanger draining into it. Or when it drys out and you smell the yummyness emmiting from the basement, you get the water jug and top it up. Maybe the coolness keeps it from evaporating as well. I am on sceptic now and the drain goes into the big O tub and then pumped away...no smell on that one.

I have only seen them in hospital facilities--never observed in a residential setting.

Wow, I'm shocked. Even 100-year old houses around here have them (never still in working order, of course).

For those of you who've never seen them, how do your floor drain traps keep from drying out?

OK, I can see why Marc might never have seen one; in LA they probably don't have basements or floor drains. But in NY & Ontario?

[kurt]

..................... how do your floor drain traps keep from drying out?

A tablespoon of mineral oil in the trap each winter.

[Terence McCann]

For those of you who've never seen them, how do your floor drain traps keep from drying out?

Motor oil.

[Marc]

..................... how do your floor drain traps keep from drying out?

A tablespoon of mineral oil in the trap each winter.

Ya startin' to sound old. My grandmother would do that to the gutter-fed cistern to kill the mosquito eggs that would otherwise hatch in the drinking water. Or is it me that's old too?

Marc

[randynavarro]

Yes, trap primers are pretty common in the northwest.

The last one I saw a few days ago was for a trap serving a catch pan under a 2nd floor washing machine.

Thanks for the replies on suggested test methods.

[sophocles]

the multifamily building in Portland where i live has utility room trap primers. the traps serve the a/c and furnace and are also fed by a usage-based trap primer.
in winter and summer (assuming folks are home), those systems will keep the trap sealed. but some drains have been clogged by debris, and the floor drains back up. 

agree that testing the primer by monitoring water flow into the trap is necessary, since we cant know whether the trap is full due to condensate or priming.