# Tankless water heater TPRV **URL:** \ **Category:** Plumbing Inspections\ **Created:** [April 18, 2018, 1:36am UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412 "2018-04-18T01:36:52Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![jsedillo](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jsedillo/32/171790_2.png) [@jsedillo](https://forum.nachi.org/u/jsedillo)\ **Post date:** [April 18, 2018, 1:36am UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/1 "2018-04-18T01:36:52Z")
I was standing near this tankless water heater when I heard the TPRV make a little spurting noise, I looked over and there was a drip of water coming out of the discharge pipe. (I had already been in the house and the hot water was functional.) Is this a normal discharge for a tankless water heater? ---
**Author:** ![sstanczyk](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/sstanczyk/32/175851_2.png) [@sstanczyk](https://forum.nachi.org/u/sstanczyk)\ **Post date:** [April 18, 2018, 3:27am UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/2 "2018-04-18T03:27:34Z")
Most likely a PRV, not a TPRV. Did you check? ---
**Author:** ![jsedillo](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jsedillo/32/171790_2.png) [@jsedillo](https://forum.nachi.org/u/jsedillo)\ **Post date:** [April 18, 2018, 1:19pm UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/3 "2018-04-18T13:19:08Z")
Ok, thanks, PRV. The question still is : why did it emit a puff of water. I have never seen one do this. The house was vacant and the utilities were on. ---
**Author:** ![jfrederick](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jfrederick/32/58314_2.png) [@jfrederick](https://forum.nachi.org/u/jfrederick)\ **Post date:** [April 18, 2018, 1:39pm UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/4 "2018-04-18T13:39:23Z")
> [@jsedillo](#): > > Ok, thanks, PRV. The question still is : why did it emit a puff of water. I have never seen one do this. The house was vacant and the utilities were on. That’s what they do when the temp or pressure exceeds the ratings;-) ---
**Author:** ![jsedillo](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jsedillo/32/171790_2.png) [@jsedillo](https://forum.nachi.org/u/jsedillo)\ **Post date:** [April 18, 2018, 3:06pm UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/5 "2018-04-18T15:06:52Z")
So maybe the unit needs adjustment? ---
**Author:** ![rlewis5](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rlewis5/32/337040_2.png) [@rlewis5](https://forum.nachi.org/u/rlewis5)\ **Post date:** [April 18, 2018, 3:07pm UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/6 "2018-04-18T15:07:53Z")
> [@jsedillo](#): > > So maybe the unit needs adjustment? Replacement. ---
**Author:** ![mgratton](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/mgratton/32/58251_2.png) [@mgratton](https://forum.nachi.org/u/mgratton)\ **Post date:** [April 18, 2018, 3:20pm UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/7 "2018-04-18T15:20:14Z")
It may need an expansion tank, was there a one way valve or pressure regulator at supply valve area? ---
**Author:** ![dcossar](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/dcossar/32/1880_2.png) [@dcossar](https://forum.nachi.org/u/dcossar)\ **Post date:** [April 18, 2018, 4:21pm UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/8 "2018-04-18T16:21:13Z")
These units require regular flushing/cleaning but almost never are. That may be the cause. Cheers ---
**Author:** ![jwalter5](https://avatars.discourse-cdn.com/v4/letter/j/c4cdca/32.png) [@jwalter5](https://forum.nachi.org/u/jwalter5)\ **Post date:** [June 10, 2018, 6:31am UTC](https://forum.nachi.org/t/tankless-water-heater-tprv/123412/9 "2018-06-10T06:31:30Z")
Usually there is two obvious or inconspicuous reasons that the T and P (Temperature and Pressure) valve will leak one is that the pressure is to high and thus causing the T and P valve to leak . 2. Check the incoming pressure to make sure it isn’t to high . You check with a _water heater_]([http://jonsguide.org/best-top-ao-smith-water-heater-reviews/](http://jonsguide.org/best-top-ao-smith-water-heater-reviews/)) test gauge by screwing on to the Hose bibb. When the pressure is above say maybe 80- 90 + Lbs. it will cause wear and tear on the plumbing fixtures. Like the toilet Flush valve or what is called the Fluid master in the toilet tank. Another factor or problem thus caused by excessive pressure is that the shower valves and or the faucets can wear out faster and would need to be changed or replaced much more frequently than if you have it at 55 - 60 lbs. which the normal water pressure…