I am new to this group.
I am looking for information concerning maitenance on tankless water
heaters. My daughter has one that needs flushing and the periodic
maintmence performed. The local plumbers don't work on them and the
big city guys want an arm and leg, stating that various items are
required. They want to replace the heater at a cost of $4,500. We
think before replacing, the flushing and strainer cleaning should take
place to see what happens.
I suspect there is a knowledge base concerning these things, but I
don't know where to find them. Can anybody help?
We have done what you recommend. My daughter was trying to get a
plumber to perform the mainenance, but one doesn't install nor wprk on
tankless heaters. Another didn't want to perform the maintenance, but
wanted to enlarge the gas line and install a new heater. The gas line
meets the guidlines shown in the manual.
It takes an hour to flush the heatexchanger and clean the strainers.
The heater has been neglected, but if a new one is required, the price
quoted was excessive, like $4500. I am looking for a plumber that
will work on it.
I watched the you-tube videos on flushing one and I am willing to do
it, but I would like better information before I start.
Thanks for responding.
You left off a bunch of important stuff here...
Like age of the installed tankless water heater for one...
How "neglected" is it ?
Some "neglect" can not be "flushed out" and would
require a replacement...
Why do you expect a plumber to come out and work
on something that is old and neglected and still be
able to guarantee their work?
If this "maintenance" ends up causing more trouble
than it solves I expect you would demand that the
plumbers fix it or replace it at their expense?
Get real... Call the OEM of your tankless water
heater and ask them who is factory certified on
that type of equipment in your area... Be prepared
to pay more than you think is reasonable -- your
calls around looking for someone to service it
have indicated that the knowledge of that specific
unit is rare in your area... That a
Perhaps to harry, who doesn't have much of a grip on lucidity.
He doesn't say where he's located, but $4500 to replace a tankless
water heater sure sounds high, but of course we don't know the
specifics,. And I don't see why he should just pay more than he
thinks is reasonable. Are plumbers so stupid that they can't handle
a tankless water heater, which is just a basic gas appliance, even if
they haven't seen that specific model before?
Also, why should he just pay more than he thinks reasonable, when he's
already learned that the plumber is feeding him BS, ie that the gas
line needs to be replaced with a larger one. The OP had enough sense
to go look up the specs and find that the existing line appears to be
correctly sized. I'll bet the plumber didn't bother to do that.
Did those big city plumbers look at the unit before telling you that
it had to be replaced? Or did they just do it based on the age,
description, etc over the phone? Seems a little strange that he has
a choice between big city plumber or small town plumber. Usually,
you're limited to one or the other for practical reasosn.
We live in a suburb of Houston.
The plumber I've used for 30 years declines to work on the tankless
I've come to the conclusion, he can't make money pouring vineger
through the heater for an hour. I don't blame him if that's the case.
The big city plumber my daughter called is onr that advertises and
covers the metropolitan area. His work probably is priced using
overtime rates and I suspect he was quoting a high price.
I inspected the heater and it is a clean installation and seems simple
enough to me. I was a little spooked by the attitude that traditional
plumbers don't have the knowledge to deal with them.
I understand the video, but am concerned that there may be
considerations I don't see.
When I undertake something I haven't done before, I do a little
research before I start.
Thanks for your feed back. I have the 5gallon bucket and will be
getting a small pump to proceed. :-)
If he just Pays Out The Money, without knowing whats needed, he is
most likely going to be ripped off. Would you pay $4500.00 US to do a
swap out of a tankless that costs maybe $1200.00 and is 1-2 hrs
work? Maybe you would. Cleaning one is easy, DIY, if it has the
flushing drains installed, and if not they can be installed in a few
try and flush it but have everything needed to install a standard tank
if flushing fails.
is the tankless a gas or electric model?
tankless in general cost a fortune to service, parts are costly,
rountine maintence is necessary, power failure often means no electric
no hot water at all......:(.
these are just some of the downsides of tankless instyalls
Is there a problem with it, does it not heat well, did it work better
before? How hard is your water, these units only scale up with hard
water. Do you have a water softener? On my unit my water output is on
the top so I put in a valve that I can pour in delimer and just let it
sit and it works. I have a handy man I trust that helped me set up
mine. You need to look around for someone that only wants a few
hundred at most, to do what yours needs. You dont give enough info on
what you have or the problems.
I have all the tools and aptitude to do the job.
I was seeking information about the system. The way the plumbers are
talking, there are technical things they are not comfortable with.
I will check the filters and then flush the unit. If we decide to keep
the unit, I will add service valves.
The problem is that when taking a shower, the water suddenly turns
cold. I imagine this could be a heat exchanger issue, a sensor issue,
or a flue gas issue.
The unit is a Bosch 125 natural gas . It has not been serviced for
five years. The daughter called local plumbers and they declined to
work on it.
A new unit will sell retail for 900 to 1000 dollars. If verical space
exists in the attic were the unit is located, we probably will buy a
Rinnai. I don't know what the additional cost will be.
I'm guessing at this stage if we get a plumber to replace the unit
costs will be $1500 to $2200. I am at the age where I really don't
care to work that hard, but I will.
The plan now is to flush and service the unit ourselves and then if
change out is required, a closely monitored contractor will be used.
Two days ago, I couldn't even spell tankless water heater. :-)
Would there be anytthing to be gained by backflushing the heater?
That is, reverse the flow of the water going through the heater.
just cause a spall to come loose and clog the heater or would it be
That is the one. I think the heater is 10 years old. My daughter and
her husband have been in the house 5 years. I'll look for a
My son in law has other irons in the fire and I'm retired, so I am
happy to take it on.
Thanks guys for chiming in.
I Have a Bosch 125 Ng 117000 Btu unit, ive had it about 7 years and a
few times have had that issue but it only lasted a few seconds and
only happened a few times. Is it power vent or direct vent. You need
to test the unit as this happens probably using a volt meter on
different sensors. Its not a clogged exchanger its a saftey or
temperature sensor or gas valve issue. It could be an overheat sensor
that is bad or poor draft causing causing it to trip.
I paid about US500 for mine and I see at Nextag they sell for 7-900
depending on model. A swap out will take a pro 1 hour so that 1500.00
price is way offand that is a 20-30 yr unit, its good till the coil
One way instalers screw up instalations is they dont test your gas
supply with a Manometer to see if you actualy have enough. Does this
happen in just winter, I could imagine in winter with lower gas
pressure everywhere and other appliances taking gas your pressure to
go to low to maybe operate right.
Try testing Temp Rise, measure incomming cold waters temp, then turn
the heater on full and measure how hot the water comes out, and the
GPM, to see if you get full temp rise. To low and it indicates
insufficient gas supply, or a calcified exchanger. Do you have hard
water? Do you or your neighbors use water softeners?
I would contact bosch, their trouble shooting site and probably a
forum if they have one. I think its an easy cheap fix once you find
the issue. www.heatinghelp.com is a boiler pro site you can ask
The key to this whole project has to start with what brand and
model the tankless unit is.
Go to the website. Find out who is a local supplier. Contact the
local supplier for a referral to one of their best plumbers that
does this type tankless installation. There is a good chance they
might know who installed the original.
While at the website, you can probably get the owner's manual with
the recommended maintenance procedures if you want to do them
If it is a top of the line Noritz, you won't need any tools other
than a Phillips screwdriver.
Keep the whole world singing . . .
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