The galvanized pipe stubs are
extended and dielectric unions attached. Copper pipe is
soldered to the hot and cold connections.
Bruce W. Maki,
Connecting a new water heater is not a difficult job, but it does
require some plumbing skills. This article follows some of the
procedures used to connect a water heater to existing copper pipes.
The location of the water heater can depend on several
factors. This heater is gas-fired so it needs a chimney for exhaust
fumes, but it has a "forced draft" fan, so the vent can be
directed out the basement wall. Electric water heaters need no
exhaust venting, so they can usually be placed anywhere that makes
||The water heater is connected to
the plumbing system by a pair of threaded pipe stubs. I
applied a generous coating of pipe thread compound.
|Then I installed a galvanized
||I installed a 6" galvanized
nipple (short piece of pipe). There was not enough space to
put the union fitting directly on the stub, so I used
the 6" nipple as an extender.
|On the cold side, I did the
same, but used a 3" nipple.
||This device is a dielectric
union. It electrically separates the water heater
from the household piping.
Read more about dielectric
unions, and why they are necessary.
||A short piece of pipe was soldered
to the brass part of the union.
|Next I soldered a threaded male
adapter fitting onto the other end of the pipe. This end will
connect to a shutoff valve.
Why not use the cheaper valves, which are soldered
directly to the pipe? Personally, I'm not that good at soldering
pipe joints, and in the past I have melted the plastic components on
a few valves, especially ball valves. I probably apply more
heat to the joint than most professional plumbers do, but I don't
solder pipes every day, so I get out of practice.
(I've learned over the years that wrapping a wet rag over
the valve body helps to prevent the plastic parts from melting.
Also, using a MAPP gas torch, which burns hotter than propane, gets
the soldering done faster so there's less time for the plastic parts
to heat up.)
||One union was connected to the hot water side.
||On the cold water side, I installed a 3/4"
diameter ball valve, which only requires a quarter
of a turn to shut off the water.
The Existing Supply Lines:
||This house had been plumbed several months
before, and the plumber had tied the hot water line in with
the cold. I used a pipe cutter to remove this section.
|Even though the water had been shut off for over
an hour, I still had quite a trickle.
||With both hot and cold sides
trimmed back, I let the system continue to drain while I
prepared the other sections of pipe.
|I cut the lengths of pipe needed
to connect the cold water supply to the inlet side of the
water heater. Where possible I solder the fittings on a
||I soldered the fittings in place. I
put a metal heat shield behind the pipe to protect the
floor joists from the flame.
|The cold water line was very
close to the PVC vent pipe, so I squeezed the heat shield in
Be careful with heat shields. Make sure the heat
shield does not cause the torch's heat to build up, as in this rather
||Looking up from almost floor level...
This is a view of the pipes that connected the water
heater. Note the furnace duct directly above the water heater.
This kind of obstruction is quite common.
||A typical soldered fitting.
There is a small ring of solder visible around the joint.
By wiping the joint with a wet rag a minute after soldering, a
clean-looking connection can be made. This also removes most
of the solder flux, which can corrode the copper surface after
a few months.
|But... I used to wipe the joints
immediately after soldering, because I had worked with
experienced plumbers that did that all the time. Except
that I wasn't quite so experienced, so I ended up heating the
joint a little more than necessary (not a problem in itself)
and when I wiped the excess solder off, the solder hadn't
hardened yet, so the fitting would move, and then
harden, and this motion would disrupt the pool of liquid metal
as it solidified, or something.
Anyways, too many of these connections would leak. So I
stopped wiping the joints right away. I now spray some water
on the joint, then I wipe it.
||We used perforated steel strapping
to support the pipes. This was held in place with 1/2"
sheet metal screws.
There are many different types of pipe hangers available.
This method is probably the cheapest but takes more time than
others. Plastic pipe hangers are better because they won't
corrode and they don't make noise when the pipes expand.
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What's New Project
- Pipe Cutter
- Pipe Cleaning Brush
- Propane Torch
- Pipe Wrenches
- 15" Adjustable Wrench
- Tape Measure
- Dielectric Union Fittings
- Galvanized Nipples,
- Copper Pipe, 3/4"
- Copper Pipe Elbows,
- Silver Solder