# High limit switch on closed chamber water heaters



## Chadillac80 (Dec 22, 2012)

Is it just me or are these things crap?? Bradford Whites intake screen is so fine that the smallest amount of condensation will clog it up once calcium builds. Give me some reasons as to why not to bypass. I know it poses a fire hazard but there are many closed chamber units that don't have them.


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## rjbphd (Feb 5, 2010)

Chadillac80 said:


> Is it just me or are these things crap?? Bradford Whites intake screen is so fine that the smallest amount of condensation will clog it up once calcium builds. Give me some reasons as to why not to bypass. I know it poses a fire hazard but there are many closed chamber units that don't have them.


Replace them with Rheem.. no cleaning needed.. problem sloved.


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## Redwood (Sep 8, 2008)

Did you undersize the water heater and that is why you are having a condensate problem?


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## Chadillac80 (Dec 22, 2012)

Redwood said:


> Did you undersize the water heater and that is why you are having a condensate problem?


Huh? I'm talking about servicing a w/h not installing one. W/h's condensate regardless of there size. The venting has to be a min of 5' to allow that condensation to evaporate. And that response was far from answering my question. If it isn't the the intake screen getting clogged its the heat in the attic that make those switches pop. My question is what's so wrong with just bypassing it if the w/h is already out of warranty? It's not in any code book nor is it on all closed chamber wh's.


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## Redwood (Sep 8, 2008)

If your Code & AHJ allows you to alter appliances so they no longer meet the ANSI Specs they were designed to meet, and install & repair appliances counter to the recommendations and instructions of the manufacturer without assuming liability then God Bless Ya Go Right Ahead!

IMHO the Bradford White Defender FVIR System is by far the best one available from the Big 3 Manufacturers.

The Rheem/Ruud/Richmond comes up 2nd best as it draws combustion air from the side like Bradford White but the flame arrestor has a smaller area so there is a higher tendency for the higher velocity flow to draw in more dust and lint to foul the flame arrestor. In addition they use a glass vial of oil which breaks in the event of an FVIR event instead of a easy to reset thermal switch.

The FVIR water heaters made by the AO Smith Companies State, Reliance, American, GSW, John Wood... Well they draw in combustion air from the bottom somewhat like a Hoover Vacuum Cleaner so we'll just stop right now and leave it as a stupid idea...

As far as condensation, cold water in the tank makes condensation, when the temperature and the dew point meet, moisture in the air condenses. In a water heater when the water heater is new and the tank is filled with cold water is normally when you will see condensation. In normal usage condensation is usually not a factor unless there is a heavy draw of hot water which depletes the hot water enough in the tank enough to make condensation a factor. If this happens routinely the water heater is probably undersized for the demand...


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## Chadillac80 (Dec 22, 2012)

Redwood said:


> If your Code & AHJ allows you to alter appliances so they no longer meet the ANSI Specs they were designed to meet, and install & repair appliances counter to the recommendations and instructions of the manufacturer without assuming liability then God Bless Ya Go Right Ahead!
> 
> IMHO the Bradford White Defender FVIR System is by far the best one available from the Big 3 Manufacturers.
> 
> ...


Ok. Well what do you do when one keeps popping? Example.. 7 year old b/w, worked like a champ till now, combustion chamber keeps getting to hot, used an air compressor on the screen, changed the switch, and even installed attic fans. ( Vent is proper and w/h isn't undersized) Here in Texas the attic get pretty hot. I like your books...solution..GO!


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## Redwood (Sep 8, 2008)

> *Gas Water Heater and Attic Installation Model (s) Affected: All Atmospheric Vented Gas*
> 
> In some areas of the country, water heaters, both gas and electric, are installed in attic spaces. As with all gas water heater installations, it is very important to have sufficient combustion and dilution air to insure proper drafting of the exhaust products and safe water heater operation.
> 
> ...


If you still can't get the temperature low enough in your part of Hades...
Maybe consider a Power Vent Water Heater...


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## Chadillac80 (Dec 22, 2012)

Redwood said:


> If you still can't get the temperature low enough in your part of Hades...
> Maybe consider a Power Vent Water Heater...


I know about the heat in the attic and proper ventilation. I've been installing solar fans. The big question from h/o's is why did it work like a champ for 7 years??


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## Phat Cat (Apr 1, 2009)

Chadillac80 said:


> I've know about the heat in the attic and proper ventilation. I've been installing solar fans. The big question from h/o's is why did it work like a champ for 7 years??


What I want to know is why your avatar has three? :blink: Carry on.


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## Redwood (Sep 8, 2008)

Phat Cat said:


> What I want to know is why your avatar has three? :blink: Carry on.


Because some of us....
Sit a little taller in the saddle...
Or have 2 strikes and still have a full count....:laughing:


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## Redwood (Sep 8, 2008)

Chadillac80 said:


> I've know about the heat in the attic and proper ventilation. I've been installing solar fans. The big question from h/o's is why did it work like a champ for 7 years??


You probably did not successfully clean it to "like new."


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## PlungerJockey (Feb 19, 2010)

Has the gas valve been replaced?

You cannot or atleast I cannot get the right gas valve for the early FVIR B/W wster- heaters. You have to use the new ICON valve.

The non-icon gas valves they send out have a slightly longer nipple attached to the gas valve. Once this is installed it pulls the burner from the center of the chamber to closer to the front. Where the limit switch is. It will cause it to pop everytime.

If that is not the case. Then your probaly missing something. Are you using the correct limit switch? Is the vent clogged?

I went to a house last week that 2 other plumbers had looked at, because the W/H kept tripping. I found some small pieces of asphalt shingle stuck on the draft diverter.

In my experience the Bradford Whites are pretty solid. I think the Rudd/Rheem family is better in my area.

I see alot of propane W/H that have NG limits on them, and they don't work.

Cover your bases, but do not bypass the FVIR. Change the unit, but don't open yourself up to liabilty


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## Tommy plumber (Feb 19, 2010)

Phat Cat said:


> What I want to know is why your avatar has three? :blink: Carry on.


 







What sharp little eyes you have......:detective:......I never paid much attention to his avatar 'girl'.


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## Bill (Jun 17, 2008)

Keep it clean please.


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## Chadillac80 (Dec 22, 2012)

Thx for y'all's help. I know better to bypass it I just needed some other point of views on the subject. And I got them ;-)


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