Last week we installed an electric tankless hot water system.
Everything worked as expected for several days, so we know things were
hooked up right. For the last couple of days there has been a strange
hot water problem that no one can figure out. Here's what's
happening:
Hot water will only come out of the kitchen sink, but only if the
bathtub is running full blast. Hot water will not come out of the
kitchen sink if the tub is not running. The hot water to the kitchen
sink does not cut out as long as the bath is running.
Hot water will not come out of the tub valve or the valve in the bath
sink at all now.
Hot water will go into the clothes washer for a few seconds and then
goes cold.
IOW, the only hot water in the house goes to the kitchen sink, and
then only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked
under the house to see if there is a hot water line leak, but there
isn't.
Does this make sense to anyone out there?

On Tue, 8 Jul 2008 08:58:28 -0700 (PDT), cyd
wrote:

Last week we installed an electric tankless hot water system.
Everything worked as expected for several days, so we know things were
hooked up right. For the last couple of days there has been a strange
hot water problem that no one can figure out. Here's what's
happening:
Hot water will only come out of the kitchen sink, but only if the
bathtub is running full blast. Hot water will not come out of the
kitchen sink if the tub is not running. The hot water to the kitchen
sink does not cut out as long as the bath is running.
Hot water will not come out of the tub valve or the valve in the bath
sink at all now.
Hot water will go into the clothes washer for a few seconds and then
goes cold.
IOW, the only hot water in the house goes to the kitchen sink, and
then only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked
under the house to see if there is a hot water line leak, but there
isn't.
Does this make sense to anyone out there?

Not to me, but it might to others.

Perhaps the unit is defective, so contact the manufacturer for advice.

On Tue, 08 Jul 2008 08:58:28 -0700, cyd wrote:

Last week we installed an electric tankless hot water system. Everything
worked as expected for several days, so we know things were hooked up
right. For the last couple of days there has been a strange hot water
problem that no one can figure out. Here's what's happening:
Hot water will only come out of the kitchen sink, but only if the
bathtub is running full blast. Hot water will not come out of the
kitchen sink if the tub is not running. The hot water to the kitchen
sink does not cut out as long as the bath is running. Hot water will not
come out of the tub valve or the valve in the bath sink at all now.
Hot water will go into the clothes washer for a few seconds and then
goes cold.
IOW, the only hot water in the house goes to the kitchen sink, and then
only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked under
the house to see if there is a hot water line leak, but there isn't.
Does this make sense to anyone out there?

Do you have debris in the line before the heater that it would restrict
the flow? How about checking for debris in all fixtures and aerators?
Are there any pressure switches or activators that need adjusting? Have
you consulted the manufacturer?



--

=================================================
Franz Fripplfrappl

On Tue, 08 Jul 2008 08:58:28 -0700, cyd wrote:

Last week we installed an electric tankless hot water system. Everything
worked as expected for several days, so we know things were hooked up
right. For the last couple of days there has been a strange hot water
problem that no one can figure out. Here's what's happening:
Hot water will only come out of the kitchen sink, but only if the
bathtub is running full blast. Hot water will not come out of the
kitchen sink if the tub is not running. The hot water to the kitchen
sink does not cut out as long as the bath is running. Hot water will not
come out of the tub valve or the valve in the bath sink at all now.
Hot water will go into the clothes washer for a few seconds and then
goes cold.
IOW, the only hot water in the house goes to the kitchen sink, and then
only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked under
the house to see if there is a hot water line leak, but there isn't.
Does this make sense to anyone out there?

http://www.seisco.com/pages/service-troubleshoot.html may not be your
manufacturer, make or model, but might give you some leads.

The one which caught my attention: pipes reversed.



--

=================================================
Franz Fripplfrappl

On Tue, 8 Jul 2008 08:58:28 -0700 (PDT), cyd
wrote:

Last week we installed an electric tankless hot water system.
Everything worked as expected for several days, so we know things were
hooked up right. For the last couple of days there has been a strange
hot water problem that no one can figure out. Here's what's
happening:
Hot water will only come out of the kitchen sink, but only if the
bathtub is running full blast. Hot water will not come out of the
kitchen sink if the tub is not running. The hot water to the kitchen
sink does not cut out as long as the bath is running.
Hot water will not come out of the tub valve or the valve in the bath
sink at all now.
Hot water will go into the clothes washer for a few seconds and then
goes cold.
IOW, the only hot water in the house goes to the kitchen sink, and
then only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked
under the house to see if there is a hot water line leak, but there
isn't.
Does this make sense to anyone out there?

Sounds like a mis-adjusted, mis-sized, or failed flow sensor. When
you have a lot of flow from both tub and sink on, the unit heats, but
not when you have lower flow. A complaint with many early tankless
units was that the flow sensor wouldn't detect small flows, such as
when you have a sink tap only slightly open. I think this has mostly
been corrected by most manufacturers, but it sounds like your sensor
isn't working right.

HTH,

Paul

On Jul 8, 1:19 pm, franz fripplfrappl wrote:
On Tue, 08 Jul 2008 08:58:28 -0700, cyd wrote:
Last week we installed an electric tankless hot water system. Everything
worked as expected for several days, so we know things were hooked up
right. For the last couple of days there has been a strange hot water
problem that no one can figure out. Here's what's happening:
Hot water will only come out of the kitchen sink, but only if the
bathtub is running full blast. Hot water will not come out of the
kitchen sink if the tub is not running. The hot water to the kitchen
sink does not cut out as long as the bath is running. Hot water will not
come out of the tub valve or the valve in the bath sink at all now.
Hot water will go into the clothes washer for a few seconds and then
goes cold.
IOW, the only hot water in the house goes to the kitchen sink, and then
only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked under
the house to see if there is a hot water line leak, but there isn't.
Does this make sense to anyone out there?

http://www.seisco.com/pages/service-...eshoot.htmlmay not be your
manufacturer, make or model, but might give you some leads.

The one which caught my attention: pipes reversed.

--

=================================================
Franz Fripplfrappl

Thanks. I printed out their trouble-shooting guide and I'll show it
to my contractor when he shows up today.

The pipes aren't reversed, because it all worked fine for several days.

On Jul 8, 1:12 pm, franz fripplfrappl wrote:
Do you have debris in the line before the heater that it would restrict
the flow? How about checking for debris in all fixtures and
aerators?
Are there any pressure switches or activators that need adjusting?
Have
you consulted the manufacturer?

Yes, there could have been debris in the line. We've had lots of junk
coming out of the faucets and aerators, including one pea-sized rock
out of the tub valve. The plumber opened up all the lines yesterday
and blew pressurized air through the pipes. Also, when the plumber
was soldering one day, he used one of those dissolvable gooey beads to
stop water from coming up the pipe and bothering his soldering...
anyway, this slime keeps coming out of the kitchen sink, which I'm
sure is that dissolved bead.

The manufacturer is sending us a replacement heater, in case that's
the trouble.

That makes sense to me. Hopefully the new unit will work better. But
how would that explain the fact that hot water will not come out of
the tub, which has good flow?

On Jul 8, 8:51 pm, Paul Franklin
wrote:
On Tue, 8 Jul 2008 08:58:28 -0700 (PDT), cyd
wrote:



Last week we installed an electric tankless hot water system.
Everything worked as expected for several days, so we know things were
hooked up right. For the last couple of days there has been a strange
hot water problem that no one can figure out. Here's what's
happening:
Hot water will only come out of the kitchen sink, but only if the
bathtub is running full blast. Hot water will not come out of the
kitchen sink if the tub is not running. The hot water to the kitchen
sink does not cut out as long as the bath is running.
Hot water will not come out of the tub valve or the valve in the bath
sink at all now.
Hot water will go into the clothes washer for a few seconds and then
goes cold.
IOW, the only hot water in the house goes to the kitchen sink, and
then only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked
under the house to see if there is a hot water line leak, but there
isn't.
Does this make sense to anyone out there?

Sounds like a mis-adjusted, mis-sized, or failed flow sensor. When
you have a lot of flow from both tub and sink on, the unit heats, but
not when you have lower flow. A complaint with many early tankless
units was that the flow sensor wouldn't detect small flows, such as
when you have a sink tap only slightly open. I think this has mostly
been corrected by most manufacturers, but it sounds like your sensor
isn't working right.

HTH,

Paul

On Jul 8, 11:58 am, cyd wrote:
Last week we installed an electric tankless hot water system.
Everything worked as expected for several days, so we know things were
hooked up right. For the last couple of days there has been a strange
hot water problem that no one can figure out. Here's what's
happening:
Hot water will only come out of the kitchen sink, but only if the
bathtub is running full blast. Hot water will not come out of the
kitchen sink if the tub is not running. The hot water to the kitchen
sink does not cut out as long as the bath is running.
Hot water will not come out of the tub valve or the valve in the bath
sink at all now.
Hot water will go into the clothes washer for a few seconds and then
goes cold.
IOW, the only hot water in the house goes to the kitchen sink, and
then only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked
under the house to see if there is a hot water line leak, but there
isn't.
Does this make sense to anyone out there?

When you say "hot water will not come out of ...", do you mean that
water comes out, but it is not hot -- or do you mean that no water at
all comes out?

On Jul 10, 7:17 am, Pat wrote:
On Jul 8, 11:58 am, cyd wrote:



Last week we installed an electric tanklessho****ersystem.
Everything worked as expected for several days, so we know things were
hooked up right. For the last couple of days there has been a strange
ho****erproblemthat no one can figure out. Here's what's
happening:
Ho****erwill only come out of the kitchen sink, but only if the
bathtub is running full blast. Ho****erwill not come out of the
kitchen sink if the tub is not running. Theho****erto the kitchen
sink does not cut out as long as the bath is running.
Ho****erwill not come out of the tub valve or the valve in the bath
sink at all now.
Ho****erwill go into the clothes washer for a few seconds and then
goes cold.
IOW, the onlyho****erin the house goes to the kitchen sink, and
then only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked
under the house to see if there is aho****erline leak, but there
isn't.
Does this make sense to anyone out there?

When you say "ho****erwill not come out of ...", do you mean tha****ercomes out, but it is nothot-- or do you mean that nowaterat
all comes out?

Cold water comes out.

On Jul 13, 11:29 am, cyd wrote:
On Jul 10, 7:17 am, Pat wrote:



On Jul 8, 11:58 am, cyd wrote:

Last week we installed an electric tanklessho****ersystem.
Everything worked as expected for several days, so we know things were
hooked up right. For the last couple of days there has been a strange
ho****erproblemthat no one can figure out. Here's what's
happening:
Ho****erwill only come out of the kitchen sink, but only if the
bathtub is running full blast. Ho****erwill not come out of the
kitchen sink if the tub is not running. Theho****erto the kitchen
sink does not cut out as long as the bath is running.
Ho****erwill not come out of the tub valve or the valve in the bath
sink at all now.
Ho****erwill go into the clothes washer for a few seconds and then
goes cold.
IOW, the onlyho****erin the house goes to the kitchen sink, and
then only when the tub is running.
Other info: the bath valve is a single-control type. we tried
replacing the mixing valve in the tub twice; no effect. we looked
under the house to see if there is aho****erline leak, but there
isn't.
Does this make sense to anyone out there?

When you say "ho****erwill not come out of ...", do you mean tha****ercomes out, but it is nothot-- or do you mean that nowaterat
all comes out?

Coldwatercomes out.

UPDATE: PROBLEM SOLVED

It turned out that most of the problem was with the water heater
itself. We swapped a new unit in and sent the old one back. CL here
was right--the problem was with the flow sensor. The unit couldn't
tell when a low-flow faucet wanted hot water, so the tub had to be
running so there was enough hot water draw to kick in the heater. But
there was also another coincidental problem. When the contractor took
the tub valve off to replace the mixing valve, it was put back in in
such a way that the faucet handle couldn't be turned far enough to
"ask" for hot water, so that's why the tub faucet wasn't kicking out
hot water when we thought it should/could. Thanks for all of your
theories and suggestions.