Things are what they are Linus 
Somebody call Meeker, he can explain this in more detail:D
TPR is what we call all valves on the water tank! Not all work on temperature and it would be correct to call it TPR according to what I have seen.
To say that it is not is what will create a problem.
It either works on pressure or temperature and I’m sure not everyone here can read the TPR tag so the only time we need to watch out is when there is a WATTS 210 unit installed where the TPRV used to be.
TPR has a specific meaning Kevin. Period.
Temperature
Pressure
Relief
And it is Watts 210 :roll:
OPPS! thanks for the correction 110. I will still call it a TPR on my report unless I can see the tag say PR and you should only see this with this type of set up.
The CA Code requires a pressure-relief valve to be used in conjunction with the Watts 210 gas shutoff, regardless whether or not an expansion tank exists on the system.
Exactly
Same here Jeffrey!
Certified and listed by CSA approval.
and please tell us where your area is by adjusting your profile.
Ok will do
Must see for those who haven’t seen this clip on water heats…
In looking at the manufacturer’s installation instructions supplied by Jeff Pope in post #2, I do not see an option for an expansion tank. They specifically refer to a PRV in each of their 3 illustrations, not an expansion tank.
[FONT=Helvetica-Bold][size=2]2009 IRC SECTION P2803[/size][/FONT]
[size=2][FONT=Helvetica-Bold]WATER HEATER RELIEF VALVES[/FONT][/size]
[FONT=Times-Bold][size=2]P2803.1 Relief valves required.[/size][/FONT]
[FONT=Times-Roman][size=2]Appliances and equipment [/size][/FONT][size=2][FONT=Times-Roman]used for heating water or storing hot water shall be protected by:1. A separate pressure-relief valve and a separate temperature-relief valve; or
[/size][/FONT]
[size=2][FONT=Times-Roman]2. A combination pressure-and-temperature-relief valve.
[/FONT][/size]
Where is the exception for the Watts 210 device?
More important question is.
Does the 2009 IRC or any code trump the WATTS 210 Installation?
The most important question is what does your local AHJ require?
Where the code is less restrictive than the listing or manufactures instructions then you follow the listings and/or instructions.
I would say Watts is taken on quite a risk to take the place of a Temperature pressure relief valve but I guess this is just me.
The Watts 210 valve in conjuction with a pressure relief valve is a TPR valve and in my opinion a better setup.
Think about it --It an over temp condition occurs with a tradtional TRP the valve opens and lets out water, it will let out water as long as the condition continues. With a Watts 210 if an over temp condition occurs it shuts the gas off, condition stopped until proper repairs or replacement.
Pressure conditions a TPR and PRV both work the same. Remember a PRV MUST be installed with a Watts 210
Watts is one of the leading manufacturers of TPR valves
Not enough info on WATTS 210 to make a stand on if it is a better set up then the WATTS TPRV. I do agree with your last statement however some have had problems with the design and I can’t figure out why they would change to this when they could design TPRV together with a shut off for gas.
JMO
That would be option 1 from the IRC (same basic provisions in the 2000 thru 2012 IRC). Most areas are on IRC based codes, and they can be used as a guide for an HI even if they are not adopted.
The watts 210 is classified as a separate temperature relief valve (TRV), as it shuts off the gas when high temperatures build up, relieving the system from any further build up. The valve is designed to shut off the gas before pressures get excessive, generally before a pressure-relief valve (PRV) activates. But a PRV is still required. Attached is a diagram from Code Check explaining the options.
I think the Watts 210 temperature-relief valve (TRV) installed with the required pressure-relief valve (PRV) is a better option than the combination temperature-and-pressure-relief valve (TPRV) which can flood a basement if the water heater control fails (and they do fail sometimes).
JMO & 2-Nickels …
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