On Tue, 23 Aug 2016 05:33:09 -0700 (PDT), trader_4 wrote:
I took apart another water heater today, and found interesting thigns.
The anode was white and mostly gone.
It took an 8-foot long pipe to get the 27mm plug out (but the water heater
was spinning which made it harder).
Both the hot and cold water nipples have some kind of plastic restrictor in
The flue had a spiral pipe going through it.
The safety valve has a spring inside and was gunked up.
The output valve was all gunked up with white creamy stuff.
The thermostat screws off (using a hammer!) and it had a six inch or so
long tube going into the water tank which was all gunked up.
Rust is everywhere.
But I was easily able to remove the thermocouple from this water heater
(but not from the AO Smith water heater).
On Tue, 23 Aug 2016 20:12:50 -0000 (UTC), Jerry Peters wrote:
I'm not sure of anything but that's what the AO Smith technical support
told me on the phone.
Taking the suggestion from others, I measured the headroom to only be about
10 inches above the water heater - so I don't really think I can get the
old anode out without removing the entire water heater, which I don't
really want to do.
Doesn't seem like it, especially if it's part of the water inlet tube.
For low clearance separate anode rod applications there's a special
replacement rod that has periodic narrow sections, so you can bend
it to get it to fit.
On Sat, 20 Aug 2016 08:24:06 -0400, Retired wrote:
Thank you for locating that training information as it sure does seem like
they designed the $10 thermocouple to not be replaced easily!
The existing thermocouple is attached at two points, one of which is
screwed on at the S-shaped 180 degree C thermoswitch (which seems easy to
remove) but the other of which is seemingly firmly attached to a plate that
also has the pilot light tube just as firmly attached.
So it seems that the thermocouple can't be 'wiggled' out, although I
haven't tried using real force yet.
It's only slowly dawning on me that the thermal cutoff switch (TCO) is
making the thermocouple not "universal".
That manual was *fantastic*.
Thank you for finding that!
I'm not sure how you knew I had an AO Smith hot water heater, but I do.
I called the residential service number listed in that manual at
800-527-1953 (x2 x2 x2 x1) and spoke to a very nice support person who
explained that there are two filters that need to be cleaned just as
described in that wonderful training manual.
1. Cordorite (she called it chromatic) anti-flame filter
2. LDO (she called it metal mesh) dust and anti-flame filter
The lady at AO Smith asked for my serial number, and given that, she told
me what you said, which is that the thermocouple with Thermal Cutoff Switch
is not replaceable.
She said I need the $88 MSRP pilot assembly PN 9003455005 which she said I
should be able to get in San Jose at:
- Slinky Brothers 408-494-7948 (7-4:30 M-F)
- RV Cloud 408-378-7948 (they don't sell AO Smith anymore they said to try
a place named "rubenstein on monterey highway who is not open on weekends)
- TW Smith 408-249-9880 (they're not open on weekends)
On Sat, 20 Aug 2016 14:02:54 -0400, Retired wrote:
That manual was great. Nice color pictures. Nice explanation.
And it had the all-important AO-Smith 800 number which is really good (and
far better than Sears and Honeywell, both of which were horrid).
I'm amazed that your image search worked, but I appreciate you doing that
as the sticker on the side of the AO Smith water heater had a sears number
so I had called them first (and wished I had not) since they gave me the
wrong part number (which I could tell was wrong from looking up what it
I called the AO Smith people back and got another nice person, who kindly
is sending me, gratis, an AO Smith Filter cleaning kit PN 9006477005.
Googling, here is a picture of what I think they're sending me:
That google search also found this 2015 AO Smith parts catalog:
This seems to show two part numbers for the propane pilot assembly:
9003455005 & 100109243
I wonder if I should add the sacrificial anode to my list of parts to get?
Mine is under the hot water nipple, where the part number includes the hot
water nipple where a minimum order is $50 at (800) 433-2545
AO Smith Sacrificial Anode 9009148005 $38 + $10 UPS Ground
Do you guys replace anodes at around 10 years?
On Sat, 20 Aug 2016 06:00:10 -0700 (PDT), trader_4 wrote:
Thanks to Retired, the moment I talked to the nice lady at the AO Smith
phone number in his training manual, I realized that the thermal fuse is a
180C thermal cut off which self resets after a few minutes.
But I don't think the TCO is my problem. I think my problem is the
thermocouple but sandpapering the 2-inch thermocouple last night seems to
have helped keep the pilot going so I am ok until Monday when I can call
local suppliers for the $88 AO Smith pilot assembly part number 9003455005.
However, what I didn't know was that the nice AO Smith lady told me that I
should be cleaning two filters on the water heater every six months, which
are the flame arrester (non replacable) or filter screen (replacable) which
she said is explained in a video here:
She also referred me to a filter-cleaning PDF here:
On Friday, August 19, 2016 at 9:21:44 PM UTC-4, Danny D. wrote:
Why do you think the resistance matters? Did you put a replacement one
without the thermal fuse in and does it work? If it does, end of story
on the resistance part.
The real issue I see is if this is just additional protection or is it
protection in place of other protection that a typical WH would have?
I would guess it's probably additional, but IDK and it's your WH.
I'm not a plumber so I don't know if the resistance matters or not, but I
do know that the thermocouple generates 30mv which is puny so any
additional resistance to the 24 inches of wire could make a difference and
I don't know what the resistance of the 180C thermal cutoff (TCO) is.
If the 180C thermal cutoff adds appreciable resistance, then the resistance
of a 24-inch universal thermocouple will be different than the resistance
of this 24-inch thermocouple with TCO such that it won't be 30mv anymore.
But putting a replacement thermocouple seems to be far more difficult than
people make it out to be, simply because AO Smith designed this as a
non-replaceable part. It can only be replaced as a "pilot assembly", part
On Sat, 20 Aug 2016 05:58:32 -0700 (PDT), trader_4 wrote:
I think resistance matters because we're talking millivolts here, but most
people, from what I've read, seem to match resistance simply by matching
length - so for me - that part is easy since it's a 24-inch long
I'm ok without the "additional protection" which, as I understand it, only
comes into play when the bottom of the water heater is at a certain
temperature high enough to blow the thermal fuse.
Since I can read a "180" on that thermal switch, for now I'll assume it
triggers at 180 degrees although I don't know if that is C or F.
Given 180C = 356F and that 180F = 82C, I guess it could be either way as
neither temperature should happen in a house - but it's probably C.
Rest assured, I would love to put in the $10 24-inch 30mv Honeywell
CQ100A1013 "universal" replacement thermocouple - but it just will never
fit unless I entirely rebuild the bracket assembly.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.