Replies

1. 
   Guest_ | Nov 17, 1999 07:24am | #1

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   I believe that is a water source for keeping water in the drain's trap in case it is syphoned out or evaporates. The importance of keeping water in a trap is to prevent sewer gases from flowing through into the house.

   Pete Draganic

1. 
   Guest_ | Nov 17, 1999 07:26am | #2

   *How does a "primer" work?

1. 
   Guest_ | Nov 17, 1999 07:42am | #3

   *Are you sure they don't mean PVC primer? I know in some townships around here they look specifically for the purple color of the purple PVC primer on drains.

1. 
   Guest_ | Nov 17, 1999 07:50am | #4

   *For a short product sheet on a drain primer (these are in Adobe Acrobat format, so you need that on your computer to view these) see:http://www.mifab.com/usa/mi-tsp.pdfFor the installation instructions and diagram see:http://www.mifab.com/usa/M-500-INSTR.pdfAnother diagram is at:http://www.repwars.com/detdwris.html

1. 
   Guest_ | Nov 17, 1999 08:11am | #5

   *Just goes to show, you learn something new everyday.

2. 
   Guest_ | Nov 17, 1999 09:40am | #6

   *I've only seen them on commercial jobs. It is essentially a supply line with a spigot over the floor drain. I reckon that ever so often you give it a squirt to make sure you keep the floor drain trap full. I suppose it is there for floor drains that don't get much use otherwise.I'm pretty sure their not talking about the purple stuff. If they are concerned about primer on the joints, wouldn't a pressure test be suitable for testing the integrity of the drain system?Pete Draganic

3. 
   Guest_ | Nov 17, 1999 06:57pm | #7

   *I'm no plumber, but I've been told that the purple primer is not necessary when doing drain lines, "a waste of money". I used it anyway (not that much money).Rich Beckman

4. 
   Guest_ | Nov 17, 1999 08:52pm | #8

   *Drain primers are code here in SoCal, even for residential work. They are fairly typical in residential applications such as laundry rooms, where the homeowner does not want an overflow tub installed around the washer. But because the floor drain will not be used daily (or at all for that matter), some arrangement must be made to keep water in the trap. I have also been required to use them for kitchens and bathrooms, where the drain will not be constantly used. It is a judgment thing in the inspector's discretion.A floor drain's trap must remain wet. If the water in it evaporates (in any low use application, not a floor sink), there will be no water in the trap to prevent sewer gas from entering the home. So, I install a 1/4" line, sweated in from the nearest source down the joists to the drain, and it enters the floor drain below grade, and just barely drips into the trap. The valve/spiggot is generally on the wall in an unobstrusive place. The homeowner controls the flow, and can shut it off if he/she desires, but it is desirable to keep the traps wet.Hope this helps.

5. 
   Guest_ | Nov 18, 1999 05:29am | #9

   *I noticed the same thing that Scooter describes in my new house, just now getting plumbed, near Portland, OR. I have an attached greenhouse with a drain in the floor, and I saw flexible copper tubing attached to the trap. The plumber told me it was to ensure water remains in the trap in infrequently used drains, just as described above. Don't know whether it's code in Oregon or I just have a good plumber. Had to be a cheaper fix than buying that Mifab attachment. Except I can see an owner forgetting to control the flow. Now I'm curious...gotta go find where this spigot is.

6. 
   Guest_ | Nov 18, 1999 06:19am | #10

   *There must be some sort of device involved to prevent a cross connect or waste water could be drawn into your potable water if there was ever a water main break.

2. 
   Jack_Durre | Nov 19, 1999 12:16am | #11

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   On commercial installations, it's common to see the supply line originate from the flush valve of a water closet. That means that each time the toilet is flushed, a small 'shot' of water is delivered to the trap. If you can find some sort of similar "automatic" method to keep the trap filled, you're home free.

   With the spigot mentioned, I would be concerned that the homeowner would forget his/her "duty" and allow sewer gas to enter. It _could_ be a safety hazard; in a laundry room, for example, with a gas dryer or water heater...those sewer gases could ignite.

1. 
   RCman | Nov 19, 1999 05:37am | #12

   *Here in our chemistry lab in Delaware, these primers do not exist (building 8 years old, $$$$$$, very hi-tech) Every so often, someone upstairs drops a sulfur compound down the drain and fumes us out. Out come the buckets to fill the traps in the floor drains. . . So much wasted time calling HVAC people, plumbers, OSH,evacuating etc. You would think they would have put them in!

3. 
   Guest_ | Nov 21, 1999 07:19am | #13

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   Watts makes an automatic drain primer valve. It is for floor drains that will be mainly unused. The valve connects to the cold water supply line for the utility sink, tub, toilet, etc. Every time the pressure drops or surges (don't remember which) from a valve opening and closing it sends a small shot to the drain. The valve is fully automatic, basically reliable (install behind an access panel) and not too expensive. There is a small copper line plumbed to the drain and usually just drilled into the side of the drain fiitting above the water level. Seal it with caulk and then pour concrete. For non-slab applications, get a brass drain fitting and solder the copper in. For PVC drains tap the side of the fitting and install a compression fitting. The valve takes care of the vacuum break as well.

   -Rob

4. 
   Jody_Siegner | Jan 04, 2000 11:38pm | #14

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   I just got busted because the floor drain does not have a primer. What the heck is that?