House is 62 yrs old... Water heater went out. Replaced it.
Now, the hot water won't flow to the kitchen, bathroom sink, or
bathtub. Cold water runs fine.
The debris in the pipes has blocked the flow (water heater is running
Is there a way to back flush or blow the pipes out.
Or, do I need to repipe? I now live in a cold water flat :)
You should be able to flush it out by reversing the flow. There's a good
chance it will work since the blockage is very recent. The debris will go
back into your brand new heater but there shouldn't be much of it - you'll
get rid of it next time you flush the heater in a few years.
* Shut down the heater, especially if it's electric
* Close the heater's cold water inlet valve
* Do *not* open the pressure relief valve
* Connect a garden hose to the drain valve at the bottom of the tank and
put the other end of the hose into a toilet or outside where noone can
come in contact with the hot water that will come out.
* Open the drain valve
* Go to the faucet that does not work and block it. If it has an aerator,
you can unscrew it, put a dime coin and screw it back. Else just wet a rug
and hold is against the faucet's outlet really tight.
* Open hot water, then cold water at the faucet, both all the way.
* It will probably take a just couple seconds of cold water entering the
hot water lines through the mixer in the faucet to push any
debris/sediment in the lines out. You should hear water rushing through
the faucet, hopefully not much of it fountaining all over the kitchen :)
* Close the cold water valve on the faucet but not the hot.
* Restore the faucet (i.e. remove the dime etc.).
Another way to reverse the flow might be to do this, assuming you have
the proper set up.
If you have an exterior cold water spigot that is at street pressure
and a laundry sink with a hose adaptor, you can run a hose from the
spigot to the sink, then turn on the spigot and the hot water side of
The street pressure should over-power the hot water house pressure (of
which you probably have none at this point, anyway) and push cold
water into the hot water pipes.
I know this because I have a street pressure cold water spigot and a
house pressure hot water spigot outside my garage. I have a Y hose
that connects them to a garden hose. If both exterior spigots are on
and the hose is off, opening any faucet in the house will reverse the
flow in the house. I'll get warm water from the cold faucets and cold
water from the hot faucets.
It really, really confused me the first few times it happened, but
once I figured it out, it all made perfect sense.
I've seen some success in using compressed air to
do it. However the other factor is, if it's that bad, what
condition are those pipes really in and is a flood in
the future? First question, are the pipes galvanized?
If they are then I'd say it's time for a re-plumbing.
Another factor is if the water flow is good or is it
noticeably weak. Those pipes decay inside, with the
passage getting smaller over time.
Yep..thought of that too! You know that pesky red shut-off right above
the WH to stop water from draining down when the pipe is removed from
the heater? I wonder if that has been turned back on.
I trusted the OP when he said "The debris in the pipes has blocked the
flow (water heater is running perfectly)."
I also wondered what that meant and how he knew.
I'd like to hear from the OP to verify that that he is not in the US.
The term "cold water flat" may just be a blast from the past as that
was a common term for low-end apartments here in the US.
I could quote Wiki, but I avoid that at all costs, so I'll point you
Cold water flats were common in the tenements of NYC, Chicago,
Detroit, etc. in the early-to-mid 20th century. They were referred to
I'm not sure what you mean by "local".
If you Google around, you'll find mention of them existing NYC,
Detroit, Chicago, Boston, New Jersey, San Francisco, London, Paris,
I guess you could consider it a local term same as you might consider
"tenement" a local term. You'll only find them in cities, so I guess
the term would be local to a number of cities.
I think anytime you disrupt the normal flow of water
whatever obstructions there are can then dislodge,
travel down the pipe to a place where it's almost
blocked, and lodge there. Kind of like what happens
to us with coronary artery disease.
I've seen houses where similar happened, like draining
the water for winterization. In this case, the pipes were
partially drained, air introduced, probably restarted with
a surge instead of slowly, etc. producing turbulence,
which then can dislodge all the debris inside.
Not a bad idea. Very likely the aerators will need to be
cleaned anyway, so taking them off to check now would
be a good idea.
You probably have to go to each faucet and clean out the aerator and
cartridge, or washer depending on the type of faucet. Back flushing
won't catch that stuff. Try one at a time, easiest first and see how
it works out.
Once the facet is apart, open the shut-off valve and flush a bit of
water before assembly to clean anything else in the pipe leading to
On Fri, 6 Jul 2012 09:54:38 -0700 (PDT), DerbyDad03
shutting off the service valve to the water heater and opening the
drain, THEN connecting from the hot to cold will do it. Just cap the
laundry tub faucet, open the hot water tap, then open the cold, and
the cold water fill force it's way back into the heater, forcing water
out the drain of the heater (which you should have a hose on, running
to the laundry drain).
On Fri, 6 Jul 2012 08:29:55 -0700 (PDT), 7 LAMPSTICKS 7 FEASTS 7 AGES OF
You did clean out the aerators on those faucets, right? Those clog
right away. If you dont know what they are, they're the screens on the
ends of the faucets. They unscrew. Unscrew them and clean them. Let
the water flow for a few minutes before you put them back on.
If it's actually the pipes, shut off the cold water valve at the water
heater. Unscrew the union for the hot water pipe above the tank. Hook
your garden hose to an outdoor spigot, or laundry tub in your house.
Hold the hose tight against the faucets, with the aerator removed, and
faucet HOT turned ON, or use a hose with clanmps to get a tight seal.
Have a helper turn the water on and off at the spigot (water source).
Do this at all the faucets that are clogged.
Besides the aerator, the other thing that regularly clogs are the
shutoff valves under the sinks, and the supply tubes. Sometimes just
removing them will solve it. Replace these shutoff valves and supply
tubes if needed, or just unclog them.
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