most helpful places to install unions

Boon

Folks,

I like the idea of putting unions on the hot & cold lines on the boiler, the buffer tank, and the indirect DHW heater. Does anyone do this? Seems it would make service easier in the future. Other than expense, is there a reason not to do this? or good reasons to do it?

I did see other threads on the wall that talked about unions on gas lines (downstream of appliance shutoff) and not in concealed (or could be concealed) locations. I didn't see anything in the code under hydronic piping that said unions were either required or illegal.

Thanks
Boon

heathead

The cost goes up when you use unions. With that said the labor rate to change something is much more that the cost of unions. Di electric unions are great for dissimilar metals. I used Webstone Vales that work as valves and unions at the time of boiler install and when I had to disconnect my indirect water heater to replacing flooring it couldn't have been easier. The cost was higher the first time but with out them it would have cost much more to move the water heater that the cost of the valves with build in unions.

lchmb

I'm not a fan of them on copper piping in and out of a boiler or indirect..I see to many leak over time and honestly it only takes me 2 seconds to cut the pipe..why charge extra when it's not needed...we all do it a different way...;)

SWEI

We use them (mostly in the form of Webstone union ball drains) on boilers, indirects, and larger expansion tanks. Makes repair and replacement a walk in the park.

I still have a few of their now-discontinued union ball valves on hand. Anyone know another manufacturer for those? Legend has one press x NPT model but I haven't found a full line of them from anyone else yet.

ChrisJ

SWEI said:

We use them (mostly in the form of Webstone union ball drains) on boilers, indirects, and larger expansion tanks. Makes repair and replacement a walk in the park.

I still have a few of their now-discontinued union ball valves on hand. Anyone know another manufacturer for those? Legend has one press x NPT model but I haven't found a full line of them from anyone else yet.

Are you sure they're totally discontinued?
A lot of their stuff was discontinued as they came out with lead free versions. Or, is it still "low lead, just, lower" ? I never looked at the new standard.

hot_rod

Maybe now that Nibco owns Webstone, they will beef up the offering?
Nibco Northern Indiana Brass Company

Tinman

I rarely use them except when they come on the parts that I use like fill valve/back flow combos and hydraulic separators.

MikeL_2

I like to use unions when connecting cast iron radiators or base board, and sometimes it's helpful to have a union on the relief valve discharge piping. When prefabricating an iron pipe manifold, we'll include a union in a convenient location. We also use unions ( & swing joints ) when twinning oil tanks, on the fill & supply piping.
We use flare unions often while connecting copper oil line piping, and we always prefer to install tempering / mixing valves with union connectors.
Unions are handy for many plumbing installs - toilets, lavatory supplies, well tank pressure switches, tubular traps and wastes, disposals, washing machines, dishwashers, ice makers, sewage ejectors, dwv piping, condensate pumps, faucets, hand held showers, garden hoses, water filters, back flow devices & PRVs, check valves, and more...........

NY_Rob

Here's how HTP recommends you install their UFT boiler with an indirect... I count eight unions used.

ChrisJ

NY_Rob said:

Here's how HTP recommends you install their UFT boiler with an indirect... I count eight unions used.

Robert O'Brien,
Thoughts?

EzzyT

We install unions everywhere just like its noted in the picture

ratio

If I were doing that sort of thing with any kind of frequency, I'd make up a jig to hold all the outer ends of the unions in place, & carry shop made valve assemblies. Just about anything to make that 10:30 PM Friday service call go faster!

ChrisJ

Hatterasguy said:

EzzyT said:

We install unions everywhere just like its noted in the picture

I simply do not understand the purpose of copper unions. Sure, you can remove the devices in a second or two. But a replacement device requires soldering for 1/2 the union anyway. Might as well just use a coupling. Fraction of the cost.

Not only that, but something as simple as even a water heater needs things modified 99% of the time.

We swapped my dad's 2006 Bradford White 50gal power vent out for a 2013 Bradford White 50 gal power vent and needed to lengthen everything because they changed the bottom of the heater.

rick in Alaska

I have a harder time getting unions to stop leaking then anything else. I have tried tightening them up, then backing them off and re-tightening them, but they will still leak. Usually requires me to really tighten them and then smack with a hammer.
Not a big fan of them unless I have to use them.
Rick

ChrisJ

rick in Alaska said:

I have a harder time getting unions to stop leaking then anything else. I have tried tightening them up, then backing them off and re-tightening them, but they will still leak. Usually requires me to really tighten them and then smack with a hammer.
Not a big fan of them unless I have to use them.
Rick

I don't think I've ever had one leak?

ChrisJ

Hatterasguy said:

ChrisJ said:

rick in Alaska said:

I have a harder time getting unions to stop leaking then anything else. I have tried tightening them up, then backing them off and re-tightening them, but they will still leak. Usually requires me to really tighten them and then smack with a hammer.
Not a big fan of them unless I have to use them.
Rick

I don't think I've ever had one leak?

i'm with Rick. I've had more than one leak and sometimes they have to be replaced (brand new ones).

Had a small one leak on the oil supply line to the pump.

Strange.
All of the ones I've used I think were Cello brand or whatever Supplyhouse was carrying. I've used a few of their Elkhart brand ones as well, no issues. I think I recently used 5 or 6 at my dad's house.

Maybe I'm just lucky?

Tinman

For water applications, I put some Teflon dope on the male thread that the nut tightens to and I'm able to tighten it leak free all the time.

hot_rod

Unions used on liquids seem to perform better if they are the gasket or o-ring type. O-ring unions can seal with just a hand tightening, usually.

In that HTP drawing, most 3 way valves have union connections and the pump flanges are a mechanical connection.
A lot of copper unions end up soldered together anyways, on purpose, or by default.

Tinman

And if there's glycol in the system, all bets are off. I have seen that stuff weep through the most secure screwed fittings. If anyone has any bullet-proof suggestions for that, I'm all ears.

Solid_Fuel_Man

I'm in the boat that there is no better joint than a sweat/brazed one. On iron/steel pipe unions are a must to make up many different configurations. Copper is always as much sweat at I can (like those bronze circulator flanges), I try and avoid any mechanical joint wherever possible, which includes threaded and unions. So east to cut and sweat in a coupling when replacement comes, especially water heaters. Something that must be removed frequently for inspection or cleaning like FPHX I union, but that's the exception. Just my experience.

SFM

nicholas bonham-carter

Lubricate the mating faces of the union with dishwashing liquid, and it will slide correctly into place, without the need for excessive torque, and subsequent deformation.--NBC

Mark Eatherton

Unions are mandatory under all plumbing and mechanical codes that I am aware of. It is required around any appliance or vessel that will eventually need replacement.

While I am not a big fan of unions because the DIYer recognizes them as "velcro", they do serve a purpose and they do expedite replacement if properly applied. Seeing a 4" shorter 40 gallon tank on top of a bunch of stacked bricks is a consequence of unions mixed with DIYer mentality. I've also seen what happens when their kids rough housed into the tank, knocking it off and breaking the gas line serving the heater.

Blocking the tanks in with piping in front of them is not my idea of "conducive to service/replacement". Hold the piping high, keeping unions and isolation valves above the tops of the vessels with drops down to the tanks so that once isolated, and drained, that the units can be changed without having to dis-assemble a bunch of pipe. It's called craftsmanship and it seems to have gotten lost in the rush for the bottom line.

ME