Water Heater Questions

[MarkSLSmith]

Folks, 

My old water heater lasted 24 years, but now appears to have expired.  I could really use your help in deciding how to replace it.  I'd like to know the following information before contacting a plumber, so as not to be on the receiving end of disinformation.

The target is a 40 gal natural gas water heater.  It is on the first floor and easy to replace (near the back door of the house).  Fancy bells and whistles are not needed.  

Problem: this water heater, and the one preceding it, had top mounted T&P valves and a drain pipe to the outside of the house through the wall.  So far I am unable to locate a new water heater with a top mounted T&P valve.  Is this no longer available?  

If I'm forced to use a side mounted T&P valve, it will be very difficult to use the existing drain pipe to the outside.  There is no floor drain.  Is it acceptable (code-compatible) to route the T&P valve outlet to the drain pan ?  My limited reading of the codes indicate this is ok, as long as the pipe terminates above the rim of the drain pan and is at least 6" gap above the floor.  This would be a whole lot easier than making a new drain to the outside of the house.  

Is there any other information I need to know?

Thanks,
Mark

[Roly]

Folks, 

My old water heater lasted 24 years, but now appears to have expired.  I could really use your help in deciding how to replace it.  I'd like to know the following information before contacting a plumber, so as not to be on the receiving end of disinformation.

The target is a 40 gal natural gas water heater.  It is on the first floor and easy to replace (near the back door of the house).  Fancy bells and whistles are not needed.  

Problem: this water heater, and the one preceding it, had top mounted T&P valves and a drain pipe to the outside of the house through the wall.  So far I am unable to locate a new water heater with a top mounted T&P valve.  Is this no longer available?  

If I'm forced to use a side mounted T&P valve, it will be very difficult to use the existing drain pipe to the outside.  There is no floor drain.  Is it acceptable (code-compatible) to route the T&P valve outlet to the drain pan ?  My limited reading of the codes indicate this is ok, as long as the pipe terminates above the rim of the drain pan and is at least 6" gap above the floor.  This would be a whole lot easier than making a new drain to the outside of the house.  

Is there any other information I need to know?

Thanks,
Mark

You may need to install a expansion tank,  most new water meters have a back flow device in them which may cause the t&p to bleed off the excess pressure.   Roly

[Snipe Hunter]

Your TP Valve is to release steam if it overheats. It's perfectly acceptable to have it discharge straight down into the pan. It should terminate about 6" from the pan. The idea is to prevent steam from blowing into your face. The discharge end of the pipe can't be threaded, pipe can't be PVC. CPVC and copper are ok.

[geek2me]

 The discharge end of the pipe can't be threaded, pipe can't be PVC. 

Is that a code requirement?  Around here builders typically do use the white PVC.

[Snipe Hunter]

Is that a code requirement?  Around here builders typically do use the white PVC.

I'm not sure about code, I'm not a code inspector. All I know is that PVC is waste pipe and can't handle much heat or pressure. The question is on the National Home Inspector's licensing test (not all states adopt the national standard) and in my training materials. If PVC pipe is inside the home, it can only be drain/waist pipe. Anything supplying water under pressure has to be CPVC or Poly (Pex) as far as plastic pipe goes. Steam blowing through a pressure relief valve is certainly under pressure. PVC is rated to be used to carry water under 73 degrees but as far as I know, not inside a home. Steam is at least 212 degrees and under pressure.

[Bob10]

Folks, 

My old water heater lasted 24 years, but now appears to have expired.  I could really use your help in deciding how to replace it.  I'd like to know the following information before contacting a plumber, so as not to be on the receiving end of disinformation.

The target is a 40 gal natural gas water heater.  It is on the first floor and easy to replace (near the back door of the house).  Fancy bells and whistles are not needed.  

Problem: this water heater, and the one preceding it, had top mounted T&P valves and a drain pipe to the outside of the house through the wall.  So far I am unable to locate a new water heater with a top mounted T&P valve.  Is this no longer available?  

If I'm forced to use a side mounted T&P valve, it will be very difficult to use the existing drain pipe to the outside.  There is no floor drain.  Is it acceptable (code-compatible) to route the T&P valve outlet to the drain pan ?  My limited reading of the codes indicate this is ok, as long as the pipe terminates above the rim of the drain pan and is at least 6" gap above the floor.  This would be a whole lot easier than making a new drain to the outside of the house.  

Is there any other information I need to know?

Thanks,
Mark

I don't know of any reason you can't just connect to the existing line going out

[Snipe Hunter]

I don't know of any reason you can't just connect to the existing line going out

Not suppose to run uphill

[Bob10]

Not suppose to run uphill

on the pressure valve?  I didn't know that, learned something new.  I was under the impression it just had to exit the structure

[MarkSLSmith]

on the pressure valve?  I didn't know that, learned something new.  I was under the impression it just had to exit the structure

Mr. Hunter is definitely correct.  The code calls for it to be free draining, ie sloped downhill.

Mark

[Snipe Hunter]

It's still a drain pipe