Water Heaters - dielectric fittings?? what are they exactly?
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handigrguy
12-07-04, 02:56 PM
hey all thanks for the replies to the earlier question about the flow control valves, what i ended up doing was removing them and installing (both sides) stainless mesh flex lines to tie in with the existing plumbing. these flex lines are attached directly to the water heater, i take it there is some type of small fitting that should go inbetween? what are these dielectric fittings and what purpose do they serve on a gas water heater?? i thought they were more for electric heaters and other electrical equip. in contact or holding water?
majakdragon
12-07-04, 03:39 PM
DIELECTRIC FITTING - This specialty fitting is used to connect two dissimilar metals together. If a dielectric fitting is not used, then electrolysis will set in, and the weaker of the two dissimilar pipes will fail. PVC is a natural dielectric fitting.
This is a dictionary type definition. If you want to see what electrolysis is, look at a copper to steel connection. You should see white mineral deposit type corrosion. This starts IMMEDIATETLY when 2 dissimilar metals touch.There is also DIELECTRIC GREASE for electrical components in your car and other electric items..This keeps the connections from corroding.
Hope this answers your questions
This is a dictionary type definition. If you want to see what electrolysis is, look at a copper to steel connection. You should see white mineral deposit type corrosion. This starts IMMEDIATETLY when 2 dissimilar metals touch.There is also DIELECTRIC GREASE for electrical components in your car and other electric items..This keeps the connections from corroding.
Hope this answers your questions
594tough
12-07-04, 05:10 PM
A dielectric union is a mechanical union which uses an insulating bushing to prevent direct metal to metal connection of the two pipes is is joining. This prevents stray electrical currents from passiing between the pipes.
A dielectric nipple is a steel nipple which is lined with plastic so that the galvanized steel on the inside of the nipple is never touched by water, hence it cannot corrode.
The flex connector you describe probably has a brass male threaded end which screws into the water heater, this obviating the need for a nipple of any kind.
This whole business of dielectrics is for me at least the most confusing and least understood topic in all of home plumbing. I don't believe I have ever heard what I consider an authoritative and well researched explanation of whether you need brass nipples, dielectric nipples, or dielectric unions.
Two things I know on my own:
1. Some manufacturers include dielectric nipples with the unit, so they nmust think it does some good.
2. Every plain galv. nipple I have seen was thourougly corroded inside and out.
A dielectric nipple is a steel nipple which is lined with plastic so that the galvanized steel on the inside of the nipple is never touched by water, hence it cannot corrode.
The flex connector you describe probably has a brass male threaded end which screws into the water heater, this obviating the need for a nipple of any kind.
This whole business of dielectrics is for me at least the most confusing and least understood topic in all of home plumbing. I don't believe I have ever heard what I consider an authoritative and well researched explanation of whether you need brass nipples, dielectric nipples, or dielectric unions.
Two things I know on my own:
1. Some manufacturers include dielectric nipples with the unit, so they nmust think it does some good.
2. Every plain galv. nipple I have seen was thourougly corroded inside and out.