# Any reason not to install a boiler pressure relief valve sideways?



## Olcrazy1 (May 28, 2013)

Most boiler safety valves are governed by same code section 1 and are designed with the inlet facing down and outlet at 90 degrees. Hot water boilers are governed by a different code I think section 4 of asme and designed differently. 

I work for a safety valve manufacturer and know valves very well. Not a good idea to mount it horizontally. They are designed to be vertical. Once it relieves chances are the stem and disc will mis align at reseat and leak. Best to install a 90 degree elbow and mount the valve vertical. Code recommends +\- 1 degree to keep proper alignment. Also be sure your valve is sized correctly to flow required capacity at relief and set pressure is equal to or less them mawp of the boilers vessel and inlet elbow is equal or larger then the valves inlet orifice size. Hope this helps. 

People have died for using mis sized valves on boilers. Be sure you know what you are doing.


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## Olcrazy1 (May 28, 2013)

Also since your are relieving steam and not water there is no reason to pipe the outlet away like a liquid valve on a water heater. It can Vent right to atmosphere. Just point it away from where someone could potentially be standing. Just curious, what manufacture safety valve you using?


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## ben's plumbing (Oct 6, 2011)

A Squared said:


> Most boiler pressure relief valves I've seen are installed upright. I'd like to install one horizontally, ie: screwed onto a nipple coming horizontally out of a tee, and with the outflow pointing straight down. Any reason why this shouldn't be done? Most water heater relief valves I see are installed this way, but I know that they're a different device.


 leave it up right and pipe it over and down ..keep pipe same size as relief opening....ben sr


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## ben's plumbing (Oct 6, 2011)

sorry for not explaining....upright because this allows opening to be piped in for areas that fall under code and that needs to piped to a drain...and because it will keep dirt and build up away from valve seat which could perhaps cause back pressure...ben sr


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## yuri (Nov 29, 2008)

It is illegal and not to code. the relief valve must be screwed directly into the boiler. if you have a nipple in between and it gets or will get plugged with rust or corrosion then it is unsafe and could turn into a bomb.


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## Canucker (May 5, 2011)

Olcrazy1 said:


> Also since your are relieving steam and not water there is no reason to pipe the outlet away like a liquid valve on a water heater. It can Vent right to atmosphere. Just point it away from where someone could potentially be standing. Just curious, what manufacture safety valve you using?


Where did they say that it was a steam boiler?


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## A Squared (Dec 19, 2005)

Thanks Oldcrazy and Ben, 

that was exactly the sort of info I was looking for. Guess I need a different plan.


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## A Squared (Dec 19, 2005)

yuri said:


> It is illegal and not to code. the relief valve must be screwed directly into the boiler. if you have a nipple in between and it gets or will get plugged with rust or corrosion then it is unsafe and could turn into a bomb.


I'm not convinced that is true. It's pretty much impossible to install a relief valve with female threads (and all the ones I've seen do) without it being on a nipple. On the boiler in question, there is no dedicated connection for the relief valve, the relief valve is currently installed on the fill connection which means that as a minimum, you have to have a tee and a nipple for the Relief Valve, unless you aren't going to have the fill connection connected so that you can fill the boiler. That has some obvious drawbacks. 

Even if there was a dedicated connection for the relief valve, and that connection had a welded nipple from the factory, it's still a nipple.


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## A Squared (Dec 19, 2005)

Canucker said:


> Where did they say that it was a steam boiler?



It's not. It's a residential natural gas boiler for hydronic baseboard heating. Relief Valve is a standard 30 psi valve.


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## Olcrazy1 (May 28, 2013)

ben's plumbing said:


> sorry for not explaining....upright because this allows opening to be piped in for areas that fall under code and that needs to piped to a drain...and because it will keep dirt and build up away from valve seat which could perhaps cause back pressure...ben sr


I have to disagree here. Crud build up at the seat will cause reduced flow and result in the valve not being able to relieve it's required capacity but it will not cause back pressure. Back pressure is present due to piping losses at the outlet of the valve not the inlet. Back pressure increases when you have many elbows or log runs of pipe off the outlet which is why I said its best to vent a steam valve to atmosphere without any discharge piping. If it is water then place a 4-6" pipe on the outlet with diameter equal to the valves outlet size then a 90 degree straight down. Long radius elbow will have reduced back pressure compared to a short radius. The whole goal is not to choke the valve if it has to relieve and use the bare minimum piping runs and turns. 

Please take a picture of the vales nameplate and post it, that will tell if the valve is designed for water or steam. Steam stamp is a "V" for asme section 1 water stamp is a "UV" for asme section 8.


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## ben's plumbing (Oct 6, 2011)

Olcrazy1 said:


> I have to disagree here. Crud build up at the seat will cause reduced flow and result in the valve not being able to relieve it's required capacity but it will not cause back pressure. Back pressure is present due to piping losses at the outlet of the valve not the inlet. Back pressure increases when you have many elbows or log runs of pipe off the outlet which is why I said its best to vent a steam valve to atmosphere without any discharge piping. If it is water then place a 4-6" pipe on the outlet with diameter equal to the valves outlet size then a 90 degree straight down. Long radius elbow will have reduced back pressure compared to a short radius. The whole goal is not to choke the valve if it has to relieve and use the bare minimum piping runs and turns.
> 
> Please take a picture of the vales nameplate and post it, that will tell if the valve is designed for water or steam. Steam stamp is a "V" for asme section 1 water stamp is a "UV" for asme section 8.


were talking safe practices for releif valves.....google kunkle safty & relief practices technical ref..pg 28.... read paragraph...reguardless of the technical crap... relief valve for this boiler is installed ... verticial.ben sr


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## beenthere (Oct 11, 2008)

As others said, it must be installed vertically.


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## Focused2 (Jan 2, 2013)

Just a city code from Milwaukee but shows everything all have suggested that you adhere to. If a strange angle to get to discharge area do not forget they make 45 degree elbows that have less restriction to flow?
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http://www.city.milwaukee.gov/ImageLibrary/User/dnscms/pdf/docs/SafetyReliefValveInstall.pdf
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Good Luck, Joe


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