CPVC for tank nipples?

The Tank CPVC for tank nipples?

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  • #12803
    arcdust
    Participant

    I’m rebuilding a Kenmore Power Miser 12 Electric and was wondering if there are any issues with using a nipple of schedule 80 CPVC to connect to the tank on the cold water port and the drain as well. I bought a brass ball valve with a hose adapter for the drain to replace the plastic valve but need a nipple to connect it to the tank. Per the Plastic Pipe and Fitting Association’s FAQs:

    (found here http://www.ppfahome.org/cpvc/faqcpvc.html)

    Should special considerations be taken to connect CPVC to a hot water heater?

    In some instances, yes. However, these considerations are based on concerns regarding external sources of heat. The hot water from the heater will not affect the CPVC.

    When connecting to a gas water hear, CPVC should not be located within 6″ of the heater’s flue, if the flue has no insulation. A metal nipple or flexible appliance connector should be used. This measure eliminates the potential for damage to plastic piping that might result from excessive radiant heat from the flue. If the flue is insulated, the instructions of the flue manufacturer should be followed.

    Since my tank is electric I should be good and it seems as if it would make an excellent dielectric. I received both anodes I ordered from here and there is an issue with the combo rod. Its the same issue as originally on the unit. The threaded end (or any part) of the nipple does not extend above the 3″ of insulation on top of the tank. It is recessed but there is enough room to get the female end of the flex line on it. I’m concerned because the plastic inside the male end of the anode does not come out and over the top of the end to provide the dielectric properties. Is the top male end of the combo anode rod steel and do I need to worry about dissimilar metals? I was thinking I could use another CPVC fitting on top of the anode rod to overcome that but I’m afraid the more connections I use the more chance that something will leak. The design of the hot water port anode is poor because there is no easy way to remove it. It is in a recessed port and you can’t get a wrench on it easily. I removed it by taking the top off the water heater and digging all the foam insulation away to make room to get a wrench on the fittings. On the cold water port I was simply going to replace it with a 5″ galvanized nipple so I could get a wrench on it next time and put a dielectric nipple on top of that with a coupling but it means more joints to leak. That’s another reason the CPVC seemed like a good idea! I hope that’s a clear enough explanation.

    #12804
    Randy Schuyler
    Keymaster

    I am not sure about the CPVC issue, but as to the combo anode, they seem to all have that kind of nipple. I got together four combos from different makers and the nipples were all the same. I’d prefer they had an FE nipple where the plastic insert covers the lip of the nipple, but that kind doesn’t seem to be a problem. Nobody has ever come back and complained, and Larry Weingarten used many of them for years in the heaters he serviced without problems.

    Randy Schuyler

    #12805
    arcdust
    Participant

    Thanks Randy…can you tell me how to connect to the combo anode? Is the male end of the anode steel and is it OK to connect copper to it even though the liner doesn’t cover the lip?

    Also, do you know of a wrench or tool that can get down inside the recess to grab and remove the secondary anode when its time to check it? I’d hate to have to remove the cover on top of the unit and dig out all the insulation to remove and check the condition of the anode every year or so. Its in my garage now and its easy while refurbing it but once its installed in my basement it would be a pain to do that on a yearly basis. Maybe its easier to just forget the secondary one and keep an eye on the primary anode? The original was the same way so it seems like a poor design from the get go. Maybe putting a nut on the bottom threads of the anode next to the tank would allow me to get a deep socket on it to pull it out.

    Thanks for your help and putting together all this great info!

    #12806
    Randy Schuyler
    Keymaster

    It’s simpler than that. Seeing as how the combo anode is anode/hot-water outlet/nipple, you just unscrew the nipple, pull the anode up as far as you can, and look it over. Corrosion is usually the most active at the top and bottom, so you can expect more to be gone in those places and gauge the condition by the rest. Rule of thumb for replacement is a total of six inches of core wire exposed.

    After I posted, I gabbed with Larry for awhile on the phone. I really hate shooting off my mouth here when I’m not sure what I’m talking about. I said as much to Larry, adding, “I don’t know what the reason is for not using CPVC for nipples, but I’m sure there IS one.”

    He replied, “There is. CPVC will shrink away from the tank steel with heat and leak.” So there is the rest of the answer. Stick with plastic-lined steel nipples for the drain valve and anywhere else. Or get used to leaks.:P

    Randy Schuyler

    #12807
    arcdust
    Participant

    This should give you a clearer Picture (Ha ha). This is the top of the water heater with the new hot water anode installed. I have removed the cover of the heater and dug out all the insulation in order to remove the old anode. I could not figure out how to remove the old one without doing this as I didn’t have a wrench or tool to reach down inside the recess to grab the anode. As it is circular and not hex shaped I couldn’t get a deep well socket or anything like that on it. The circumference of the recess is not large enough to allow and type of pipe wrench in there. I’ll post additional pictures and views below.

    I did a little more research on the Plastic Pipe Fitter Association web page and found where they indeed do not recommend installing CPVC to a metal water heater without using a metal to CVPC transition so Larry’s advice on the shrinkage/leakage issue with CVPC looks spot on!

    Attached files

    #12808
    arcdust
    Participant

    Here is a top view showing the room to maneuver around the combo anode on the left, in red of course. On the cold inlet I installed a long nipple, I think its a 5″ so I could remove it without having to take the top off and remove the insulation next time. This nipple is not dielectric so I was going to use a galvanized coupler to attach a dielectric nipple on top of it before connecting the copper flex pipe.

    Attached files

    #12809
    arcdust
    Participant

    This is what I had to do to get the old combo anode, cold water nipple and primary anode off. I took the cover off and dug out the foam insulation to get access. Otherwise there was no room to get a wrench on anything except for the primary anode with a socket and extension. I do not have any type of tool to reach down inside the recess and grab the nipple. I asked about using great stuff insulating foam to replace it when I put it back together and I think I got the nod from Larry on that approach in another post.

    Attached files

    #12810
    arcdust
    Participant

    Lastly this is the original combo anode. It has the plastic coming up and over the top lip of the nipple but it is also a heat trap. I wanted to avoid this type of trap and use the copper flex connection and inverted “U” to create the heat trap. I was hoping when I was done with the project it would be in a state to provide easy maintenance but I can’t see how to remove the combo anode without de-installing the water heater, removing the lid and digging out all the insulation again. Maybe there is a wrench that would get me down inside the recess to grab it?

    Attached files

    #12811
    Randy Schuyler
    Keymaster

    You had actually said all that in the previous string and I just forgot about it. That’s dreadful, and I really don’t know what to say. Maybe somebody else who posts here will have a creative solution.

    Randy Schuyler

    #12820
    Larry Weingarten
    Participant

    Hello: About dealing with the anode later; the way I do it is to use a coupling and lined nipple, tightly screwed to the anode. Use a pipe vise or two pipe wrenches to really snug this down. Install the unit in your heater, but don’t get it quite as tight. This way when you go to remove it later, the joint between tank and anode will come loose first. As for overhead clearance, it’s hard to change geometry 😛

    Yours, Larry

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