Hopefully this is a fairly easy question...

I'm going to replace the main water shutoff valve in our home, that no longer shuts off the water, it's an old gate valve with a ball valve.

2 questions...

- Can I use a threaded ball valve to make the connection or does it require to be a sweat connection? Is there a code requirement for this connection?

- If it requires a sweat in valve how do you keep the ball valve seal(s) from melting while heating the fitting?

Thanks for any input.

Your question is confuseing because it is either a gate valve or a ball valve. Replace the Gate valve with a ball valve for best results.

Sorry... I'm replacing a gate valve with a ball valve. Just wondering about the connectivity can it be a threaded ball valve, does it matter?

My experience as a DIYer is you can use threaded connections or sweat connections or compression connections.

Don't get just a "ball valve", get a "full port ball valve".

Depends on where your valve is located might kind of dictate the method of connection. If it's inside the house's basement and you have space all around it, you have more options. Down here in south Florida most shutoff valves to the house are placed on the riser tight against the house exterior wall. This makes it impractical to do a threaded valve because there just isn't room to swing the valve all the way around to make the connection, so if someone wants to use a threaded valve, they end up threading onto it a short piece of copper with a male adapter on each end, then solder on the "extended ends" so you end up sweating anyway.

Ball valves have teflon seats that can be subjected to higher heat. Some people would remove the handle, and wrap a wet rag around the middle to cool that area while sweating, while others would do it without any issue by controlling where the flame is directed to and not heat the area any longer than necessary. Yes some DIYers use threaded connection ball valves to extend each end so the soldering joints are not as close to the valve.

Thanks for the great info. this DIYer was about to use a standard ball valve but will now be looking for a Full Port Valve thanks to your input. Although, a gate valve seems to have even less flow than the ball valve I have now.. going Full Flow now though.

I don't mind sweating joints, I just have a problem getting larger pieces hot enough for the solder to wick, user error I guess. So, I'll be sweating a threaded end on the line from the street, which is in my basement (KY), then a threaded Full flow valve to another threaded end and then a union.

Thanks for the guidance.

1 more follow up question...

Do they make a 3/4 Full Flow FIP with a drain? Just wanting to make sure I'm not looking for a Unicorn.



Edited 1 times.

"making one" and locating one without it being a special order may be two different things, since very, VERY few people actually use one, so they will hot be stocked.

Thank you.

Seems like they are available for sweat version but no the threaded...

What would be the purpose on the main shutoff valve?

Going without.

the standard port ball valve has a slight restriction in it's design.

see if you can order a 3/4 Cu X 3/4 (m)NPT union:



install on the DOWNSTREAM (house) side of the valve

the union will act as the 'waste' instead of buying a 'stop and waste' valve

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Is a union the preferred connection type for this type of situation as opposed to a threaded male end?

you will need EITHER:

2-adapters + 1-union

OR

1-union/adapter (what i showed) + 1-adapter





what i showed is merely is a 'combination' fitting to reduce the number of separate fittings required

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

bernabeu,

if he has a union just downstream of the shutoff valve, is there still a need to have a drain on the valve? I can't think of one.

@ sum

Quote

..... the union will act as the 'waste' instead of buying a 'stop and waste' valve .....

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

The union I think makes the most sense...

I assume on the union threads any sealant is permissible like teflon tape, pipe dope or joint compound?? No issue with any of those...

for the union threads (the 'separable' part) you want ONLY a lubricant such as plumbers grease or nevr-seez

for the (m)NPT threads (going into valve) standard 'pipe dope' or PTFE (teflon)

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Plumbers grease, should that also be used on the matting surfaces of the union to fill any imperfections?

One last question... since the full flow valve isn't marked for "flow" I assume it can be installed in either direction?





Edited 2 times.

yes, either direction is A-OK


for the union 'halves' - lube the threads on the ring and the bearing 'shoulder' of the ring/body surface - the actual 'face' should mate and seal PERFECTLY with or w/o lube (the lube is to ensure tightening so the face WILL mate under 'high' pressure)

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Thanks... just want to avoid any leaks and having to revisit.



Edited 1 times.

the union 'halves' must 'mate up' (align) 'squarely' and straight AND 'make contact' BEFORE the ring is even engaged with its threads


the ring's ONLY purpose it to press the halves together NOT pull them into alignment


installing unions PROPERLY is one of the 'tricks of the trade'




barring a defective one (which usually would be spotted BEFORE installation) they NEVER leak at the 'joint' of the mating surfaces IF INSTALLED AND TIGHTENED PROPERLY



ps. you want a 'heavy' CAST adapter union, NOT a big box store thin-walled POS

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



Edited 2 times.

Cast union being similar to the following... ?

[www.nibco.com]



Edited 2 times.

PERFECT

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Also I would add that if you have a clearance problem it could determine which end of the valve you install. I hope you understand what I am trying to say. You need clearance for the valve. Just be aware if you evwr need to disassemble the valve.

Appreciate all of the advice... a cast union, similar to the one I posted, is not a common item in KY (we must be a bunch of hillbillies). Since this is the main water line I went ahead and ordered a cast unit, simply because it's cast and more substantial.

I got the clearance suggestion as well, glad there isn't a "Flow" direction as that does help with the install.

Should be apiece of cake.. thanks to all of your inputs.

Many thanks,