Replies

1. 
   arrowpov | Aug 08, 2005 05:45pm | #1

   With the reducer valve there is no place for the water to expand, when the water heater kicks on the pressure increases. I had that problem, the pressure relief valve would blow on the water heater. I installed an expansion tank for potable water and the problem was solved.

1. 
   johnmocha | Aug 08, 2005 06:15pm | #2

   sounds good - where did you cut the water tank into the line at? I would think at the water heater one the "heated outlet" side of the line. How big a tank do you recommend?
   Thanks,
   John

1. 
   johnmocha | Aug 08, 2005 07:32pm | #3

   Just remembered, its a pressure reducing valve vs a pressure relief valve. Would this make a difference in that there is no "blowoff" of water as there is with a pressure relief?

1. 
   rasconc | Aug 08, 2005 08:35pm | #4

   He was talking about the temp & pressure relief on the water heater.

2. 
   arrowpov | Aug 08, 2005 08:50pm | #5

   The pressure reducing valve is like a check valve, when your water heater heats up the water expands. If you don't have an expansion tank the water pressure in your house lines will increase. Before I had an expansion tank I put a pressure gauge in the line, when the water heater was on the pressure would rise from 55# to 150#, at that point the t&p valve on water heater would release water. I blamed the dog for the puddle on the floor before I figured the problem out.

   The expansion tank cost less than $50. around ten years ago.

2. 
   arrowpov | Aug 08, 2005 10:27pm | #6

   I put the tank just past the reducing valve on the main line. In my new home it's just on the end of a line. As long as the water has a place to expand, I don't think placement is super critical. The tank is about 12 inches round and 14 inches high.

1. 
   Shacko | Aug 09, 2005 12:29am | #7

   Expansion tanks should be on the cold side, if it's anywhere  near the water heater it should be fine.  Tank should be charged  to the system pressure, whatever you are running past the prv, charge the tank to that psi. You should have a prv valve down stream of the reducing valve. Let me get back to the original post. Luck.

3. 
   JohnSprung | Aug 09, 2005 03:32am | #8

   The expansion tank should go on the cold side.  You don't want to cook the rubber diaphragm or pay for heat dissipating from the tank.  It should also be teed in after the shutoff valve.  You don't want it to be possible to close the valve and prevent it from doing its job.

   While the expansion tank is a good idea, it might turn out that hot water expansion isn't the problem.  Regulators are fussy beasts.  They can leak due to a small piece of crud or a nick on a seat, a scratch on a piece of rubber....  There are rebuild kits, but since this is a new one, see if it's under warranty.  I finally put valves before and after mine, since I had to pull it and mess with it so much.  It's also a good idea to put a permanent gauge somewhere on the low pressure side, like maybe near the water heater.  That way you can check easily if the regulator is effing up again.

    

   -- J.S.

    

1. 
   johnmocha | Aug 09, 2005 03:43am | #9

   Ok, here's where I lob in the dumb question. Is shutting the hot water down and checking the pressure jump or lack thereof a good way of pinpointing the problem as either thermal expansion or the pressure reducing valve? Also, what is the preferred location of the outside main shutoff - before or after the pressure reducing valve?
   Thanks,
   John

1. 
   BillHartmann | Aug 09, 2005 04:24am | #10

   You want an accessible (don't know how accessible your meter pit might be) before the PRV.And reguardless if the PRV is leaky or not you need the expansion tank.

2. 
   JohnSprung | Aug 09, 2005 08:53pm | #11

   Yes, you can eliminate thermal expansion by turning off the heater -- actually just turn it from "on" to "pilot" if it's gas.  Run a little water to release any pressure that might exist, and you start with a clean slate.  If the pressure still creeps up, then it's definitely the regulator.  The expansion tank is always a good idea, even if it's a separate issue.

   As for the shutoff, you want it ahead of the regulator so you can use it when you work on the regulator.  I put a second one after the regulator to make it more convenient, so I don't have to drain all the plumbing in the house.  Did that about the 3rd or 4th time I took the regulator apart.

    

   -- J.S.

    

2. 
   HealeyBN7 | Aug 09, 2005 10:32pm | #12

   John -

   Sounds like your Wilkins valve is bad.  I just replaced the three year old valve in my father's house with the same symptoms.  There was a pin hole leak in the diaphram.  

   Dean

1. 
   JohnSprung | Aug 09, 2005 10:35pm | #13

   You can also get rebuild kits.  Regulators aren't cheap, and if you can save the brass and just replace the soft stuff, you can save some money.

    

   -- J.S.

    

1. 
   johnmocha | Aug 10, 2005 10:14pm | #14

   While I will test first to ensure its not the pressure reducing valve, I'm betting that the problem will be solved by an expansion tank. I picked one up at Lowes last night and the diagram on the package indicated that a vacuum relief should be installed between the tank and the water heater. Have the folks that put in an expansion tank put this valve in also? On a separate topic, what is the preferred method of connecting ABS to cast iron? I have some galvanized drain that needs to be replaced and it eventually connects to cast iron. It will be a two step project. The first is hooking up a sink whose drain I removed to existing galvanized. It would connect at an existing Y that has a threaded female opening (1 1/2"). I'm thinking about using an ABS male pipe thread to ABS 1 1/2" hub as the connection. I have a call into the local inspector (Seattle) but wanted to get thoughts here. Would you use teflon tape or something like Rectorseal on the threads or both to ensure a tight and leakproof connection?Thanks!
   John

1. 
   arrowpov | Aug 10, 2005 10:20pm | #15

   I don't recall a vacuum relief being required in the instructions. I currently have the tank installed without one and it functions ok.

2. 
   Shacko | Aug 11, 2005 01:06am | #16

   Yes we have installed a vacuum rellief valve in this situation [its usually required by code; its not that expensive].  The second question's answer is that you can do what you want with connecting ABS to to a threaded joint; use tape and dope,or use tape without dope, or dope without tape. Pick one, you should have no problems either way.  I hope that your future plans are to get the galv. out  That stuff is old, old, old! .  Luck.

1. 
   johnmocha | Aug 16, 2005 06:54pm | #17

   Thanks Shacko,
   I installed the tank on Saturday and things went just fine. I tried to find a vacuum relief valve but neither HD or Lowes had one - just very puzzled looks went I asked for one and skeptical looks when I showed them the diagram on the box for the expansion tank. Also a call to the plumbing inspector help line in Seattle didn't help much either. It was pretty comical in that the inspector couldn't offer an opinion on just about anything and when I asked about the code for connecting ABS to galvanized he said why don't I just replace everything. Granted the fellow I was speaking to covers an area with mostly new construction. Given that I can't get to a good plumbing supply house during lunch, I installed the tank without the valve. It seems to work fine. Pretty interesting when I shut the system down and then drained it. You could definitely tell that the tank drained after I shut down the main. The main was a bit warm from the hot water draining off the tank. My thanks to everyone for their superb advice. You make the job enjoyable and encouraged me to undertake more!Ok, a few more questions. I will be changing out some galvanized for ABS, probably more than I anticipated. It seems as though it would make sense to change out the vent through the roof with ABS also. Given ABS' reaction to light what is standard practice? Also has anyone done a remodel and left the last "leg" through the roof galvanized. It would probably be an eight foot section and if I did this I am concerned about the weight the ABS might potentially be holding up. Of course I would secure the galvanized to the studs beforehand, but....

2. 
   JohnSprung | Aug 16, 2005 10:22pm | #18

   If the roof penetration isn't leaking rain, leaving the old galv there is probably a good idea.  That's what they did on my re-pipe.  Sections that serve as venting only last far longer than those that have water running through them. Look at the cross section and interior where you cut it.  If it's not rusting away, and the roof doesn't leak, don't make trouble for yourself.  Leave it alone. 

    

   -- J.S.

    

3. 
   Shacko | Aug 17, 2005 12:50am | #19

   The vent through the roof  is fine make sure you support it where it connects to the ABS.llike I said on the original response, get rid of the most galv. that your budget will allow.  Luck