View Full Version : Dresser coupling on hot water heater

12-14-2008, 09:54 AM
Hello all..... I am a new to posting here but have been reading others' postings for the past five years, and I have to say it has been very, very helpful.

My current issue is with the line out from my Millenium hot water system back to the boiler. [Link to photos is included below.] When my father (86 years old, God bless) and I installed this, he chose to put in dresser couplings on the two lines such that exchange would be simple when I need to change the hot water system again (I suppose in ten years or so -- prior homeowner had a Milleniumin place when I bought the place and that was there for 14 years before it started leaking from a seam in the stainless tank).

That was two years ago. And he kept slowly tightening the top dresser nut because I had the tiniest of drips.... and after last winter the drip go a slight bit worse -- I presumed due to the expansion/cooling cycle of the copper pipe. As I have a very large tank, I only run the system every 4-5 days in the summer, so it barely leaked at all this past summer. However, in the past week, now that the temps are done to the twenties and the boiler is on a lot, plus the basement is toasty warm, it has started to really drip -- at the rate of about an ounce an hour.....

I have to empty the plastic container in the photo at least twice a day for the past four days.... so my question is this -- I read somewhere that there is a lot of pressure exerted on a dresser coupling if it is close to a 90 degree ellbow such that the coupling should be clamped to counteract the pressure, and I am wondering if that is my problem or if it is merely the expansion and contraction... either way, I need to resolve this as I cannot go with water leaking onto the floor.... I would like to keep the dresser couplings in place, so please provide your thoughts on a solution....

The top coupling in the photos is the one that is leaking....


I also would like to know exactly what the dresser coupling I am using is called -- I have looked at Wal-Rich's catalog of various couplings and am not sure which exactly is mine.... I'd like to get a spare on hand just in case....

And I would like to have some insight on how best to tighten it -- my father warned me about overtightening it, and has not let me tighten it -- insisting that he come over and do it for me, but I'd like some instructions I can print out and leave in a ziplock bag down there so I can somewhat "idiotproof" my diy.... With good instructions I can do just about anything.....

Thanks in advance for your guidance,

Gary Swart
12-14-2008, 12:35 PM
I believe those couplers are actually unions. If that is incorrect, I'm sure some of the real pros on the forum will quickly correct me.:D I hate making hard connections to a water heater. I use the flexible copper connectors that have female screw ends. These give you some latitude in pipe lengths and allow you to make minor position adjustments if needed.

Gary Swart
12-14-2008, 02:50 PM
I did a Google search on Dresser couplers, and I was correct, those are unions.

12-14-2008, 02:56 PM
Gary is right those are unions...if they are leaking and tight it may be because they are not straight...if you look at them before they are tightened there should be an even space between the two when they are touching before you thread the large nut on and tighten it...if the space is not even this may be your problem...

Gary Swart
12-14-2008, 08:37 PM
I this was mine, I sweat male adapters on right after the 3 valves and screw a male adapter on the nipple coming out of the tank. Then I use two flex tubes to replace the pipe and fittings.