PDA

View Full Version : Is a "T" ok off pressure valve



Peter Drougas
01-12-2008, 05:24 PM
On a boiler heating system a section of pipe comes out for the pressure release valve by about 6". But it goes to a "T" fitting. At the bottom of the "T" it is capped, at the top is the release valve. I don't know why they didn't just connect the valve directly to the first pipe and let it face down. Now with the "T" it faces out.
Aside from a discharge line missing, is this "T" allowed? I put in the report that the "T" should be removed.

James Duffin
01-12-2008, 05:32 PM
I believe Jom Is correct with his post below. In my original post I was thinking of an Apollo system not a boiler. Sorry for the error!

Jim Robinson
01-12-2008, 09:11 PM
A boiler relief valve will be pressure only. A TPR is used on a water heater or storage tank. I can't think of a good reason why the T would make a difference, although it should be piped outside or to a drain, air gap, etc.

Donald Merritt
01-12-2008, 09:54 PM
The pressure relief valve is in the wrong location and the sensor probe has been removed. A new pressure/temperature relief valve should be installed. The new valve should have male threads and be installed directly into the tank with no piping extension. There should also be a drain line for the pressure relief valve to with in 2 to 4 inches of the floor.

Don Merritt

Brandon Chew
01-13-2008, 10:14 AM
The pressure relief valve is in the wrong location and the sensor probe has been removed. A new pressure/temperature relief valve should be installed. The new valve should have male threads and be installed directly into the tank with no piping extension. There should also be a drain line for the pressure relief valve to with in 2 to 4 inches of the floor.

Don Merritt

It sounds like you are talking about a TPR valve for a water heater. The original question is about a pressure relief valve on a boiler.

Pressure relief valve

http://www.watts.com/prod_images/174A.jpg

Temperature and pressure relief valve

http://www.watts.com/prod_images/100XL.jpg

Nick Ostrowski
01-13-2008, 10:29 AM
Based upon the pictures Brandon posted, the valve Pete pictured sure looks like a pressure valve only. It seems recommending the valve be replaced with a TPR valve would make good sense.

As for where the discharge line for the valve should exhaust, it will vary by region. Being as Pete is up in New Hampshire, exhausting a line to the exterior would make it susceptible to freeze-ups. Around here in Pennsylvania, these valves exhaust indoors and onto the floor. I've never understood how having these valves exhaust into a drain line or to the exterior is supposed to help the homeowner determine if there is a problem with the unit. If you see water beneath the valve on the floor, you know it may need repairs. If you can't see anything, a problem stands to go unknown and uncorrected for a longer period of time.

Brandon Chew
01-13-2008, 10:38 AM
The original post is about a hot water boiler heating system. The relief valve is only for pressure. In homes, I've seen some installed directly into the boiler, and some installed on the piping system close by the boiler, between the boiler and the pressure reducing valve. As far as I know, either way is acceptable, and Jim's post above is correct.

Nick Ostrowski
01-13-2008, 11:04 AM
That's right. I'm forgetting that a boiler should have a limit switch installed to safeguard the system against excessive temperature rise.

Jerry Peck
01-13-2008, 12:29 PM
*To me* it looks like a T&P relief valve, if so, it was probably one of the ones with a short probe, which is why it is installed into a tee like that (the probe is down in the tee).

The next question, then, becomes: Is it acceptable to install and T&P valve were only a pressure relief valve is needed?

I would say 'Yes, provided that the T&P pressure setting is at the same pressure setting as the pressure relief valve would be. "Provided that" is the key, like saying *IF*. :)

Peter Drougas
01-14-2008, 03:04 PM
Nick is correct, in NH the discharge line simply terminates within 6 inches off the floor. Slow dripping valves can lead to freeze up if the termination point is exposed to freezing temps, as they are today.

I understand the point about exactly what type of valve it is.

So Jerry are you saying with "which is why it is installed into a tee like that (the probe is down in the tee)."; that it is acceptable to have this "T" fitting?

Jerry Peck
01-14-2008, 05:50 PM
Peter,

I don't see a problem with that tee fitting as that is only required to be a pressure relief valve, but what I am really saying is 'if the correct valve was used, the tee would not have been necessary'.

Plus, I was alluding to 'that T&P valve might not have the proper pressure setting' if it is a T&P relief valve.

Did you read the label on that valve? What was the pressure setting - 150 psi?

What is normally used on a boiler heating system like that?