Chasing a NPT fitting on a new oil tank?

MaxMercy

I just had a new 330 gallon oil tank dropped off and before I connect it this weekend, I was wondering if it was a good idea to chase the threads on the connections to make sure I don't get leaks. I read that welded in bungs can sometimes be slightly distorted on oil tanks, or are they cut after they are welded in?

Also, is it a good idea to install a ball valve in front of the fusible valve?

hot_rod

If this there is any paint or debris in the threads, clean them.  A large fitting brush may be enough.

Saw some grooves in a nipple to make a thread chaser.  

If they are damaged badly, a pipe tap may be required.

In_New_England

Can you do a pressurization test? I guess you'd need specialized equipment. I'd never have thought to check a new oil tank. I'd assume that an oil tank company would have tight quality controls on it.

MaxMercy

In_New_England said:

Can you do a pressurization test? I guess you'd need specialized equipment. I'd never have thought to check a new oil tank. I'd assume that an oil tank company would have tight quality controls on it.

The label on the tank said not to pressure test it as it had been pressure tested to something like 5psi. It also said to carefully monitor it on the first fill.. The tank is made in Canada and seems well made. Time will tell I suppose.

My plan is to put maybe 20 gallons of diesel in it to monitor the bottom connections. It will run most of the summer on that just for hot water.

STEVEusaPA

Indoor tank or outdoor tank?
Inside, by code, your first valve is supposed to be a firomatic.
Outside, firomatic valve where the oil line first enters the house, so you could have a ball valve at the tank on a gravity job.
That being said, I always put a ball valve at the tank. I've never had to replace a ball valve in over 30 years in the business. I've replaced far to many firomatics, involving having to do the vacuum trick-not something fun to do at night, very cold, snow, etc.
I've also never had a problem with having to chase the threads. Worse problem I ever had was the bung not being welded on straight, so when you screw a long pipe into the top it's way off of vertical (it's going to be off slightly when you pitch the tank).

Most important is to make sure there is no water in the new tank. I always put a bottle of additive in on first fill.

MaxMercy

STEVEusaPA said:

Indoor tank or outdoor tank?

Indoor.

Inside, by code, your first valve is supposed to be a firomatic. That being said, I always put a ball valve at the tank.

You mean you would put the ball valve before the firomatic anyway, correct?

I've replaced far to many firomatics, involving having to do the vacuum trick-not something fun to do at night, very cold, snow, etc.

I hope I never need to do that, but when you do that, do you block the vent or does that risk collapsing the tank? Do firomatics fail by leaking, or by closing off the oil that requires the replacement?

Most important is to make sure there is no water in the new tank. I always put a bottle of additive in on first fill.

Thanks, will do.

STEVEusaPA

I mean by code, for an indoor tank you can't have any ball valves, has to be firomatic at the tank, firomatic at the burner, jacketed oil line. But I'm putting a ball valve at the tank, then yes a firomatic.
Here's what I do on a gravity job:
Ball valve, expansion loop, firomatic into General Filter, Spin-on, OSV, then jacketed oil line to expansion loop into firomatic at the burner.
If I were in a state where the Fire Marshall had a say, I'd have to fight with him about the ball valve.

Apparently, they 'fixed' most of the problems with the firomatics. They'll fail close and wont open, fail open and won't close. Which is why I can close the ball valve, and swap it out-which is much safer than trying to replace it on the fly.
Actually, I've never had one leak. But I did have one fail at the burner at my house by almost entirely closing, and the high vacuum killed my fuel pump-on a night I was so tired I didn't get home until 11pm and didn't bring my service van home. So back out I go to the shop, get the van, fix my own burner, so I could get a shower and go to bed...lol.

ChrisJ

STEVEusaPA said:

I mean by code, for an indoor tank you can't have any ball valves, has to be firomatic at the tank, firomatic at the burner, jacketed oil line. But I'm putting a ball valve at the tank, then yes a firomatic.
Here's what I do on a gravity job:
Ball valve, expansion loop, firomatic into General Filter, Spin-on, OSV, then jacketed oil line to expansion loop into firomatic at the burner.
If I were in a state where the Fire Marshall had a say, I'd have to fight with him about the ball valve.

I think the way you're wording it is confusing.
You must have a firomatric at the tank regardless of other valves, not just a ball valve.

But I get what you're saying.

Curious, does anyone ever use WYE strainers at the tank before the filter? Is there ever a reason?
I'm on a strainer kick right now........

MaxMercy

ChrisJ said:

I think the way you're wording it is confusing.
You must have a firomatric at the tank regardless of other valves, not just a ball valve.

That's the question: can I go from the tank > ball valve> firomatic > General filter without running afoul of the code, or by code does it demand I eliminate the ball valve and only use the firomatic?

Right now I have a firomatic and a filter at the tank and a firomatic at the burner.

I don't see how a ball valve would leak externally even if it's in a roaring inferno, or can they?

pecmsg

Nothing wrong running a tap for 1 ou 2 turns and chasing the threads

ChrisJ

If I wanted good clean NPT threads, I'd run the nipple or valve I'm going to use in and see how it feels and looks. I.E. how far is it going to go in without me removing any material. If it's not tapped too deep already and I had room to breath I'd remove the nipple or valve and run the tap in by hand until I felt resistance. Then put the wrench or tap handle in and run the tap in a turn or so after it starts cutting.

Or.... until you feel it's tapped deep enough to get a good match with what you're using. I've had radiators and fittings that only gave me 2 turns, so I fixed them.

STEVEusaPA

ChrisJ said:

I think the way you're wording it is confusing.
You must have a firomatric at the tank regardless of other valves, not just a ball valve.

But I get what you're saying.

Curious, does anyone ever use WYE strainers at the tank before the filter? Is there ever a reason?
I'm on a strainer kick right now........

Close, but no, by code ball valves are NOT permitted, fuseable link only. But like I said, I've never replaced a ball valve, but many fuseable links. I still put a ball valve at the tank on a gravity job, then a fuseable link, because if there ever was a fire and that valve wasn't there, and could've prevented some kind of a catastrophe if it was there, I'm sure I'd be sued.

It's more for my convenience in the event of a fuseable link valve failure at the tank and how risky & time consuming it is to replace one.

I wouldn't bother with a strainer, just double filtration. Even better, an oil/water separator/filter like on my diesel trucks that I could drain the water (and in the case of heating oil tanks) sludge out of the bottom.

STEVEusaPA

MaxMercy said:

That's the question: can I go from the tank > ball valve> firomatic > General filter without running afoul of the code, or by code does it demand I eliminate the ball valve and only use the firomatic?

Right now I have a firomatic and a filter at the tank and a firomatic at the burner.

I don't see how a ball valve would leak externally even if it's in a roaring inferno, or can they?

This is the point of my angst with them. I've asked for many years, to many top experts in the field, "can anyone point me to a case where there was a fire, and the fuseable link valve 'saved the day' "?
No one has a real life example.
My cynical guess was whoever makes them, got them into the code, more for their profit.

To throw another wrench in the mix, you need a fuseable link switch to cut off electric above the burner. Now that one I agree with, even though if I ever need one I have to special order it from any supply house near me, so now I just order it online.

EBEBRATT-Ed

Yes, I saw a house that was saved by a Firomatic valve. The burner was an old Gilbert and Barker with the old Webster pump with the two square caps and the 1/4" shaft (forgot the model "W"?)

Well, the burner had "settled" and the blast tube was pitched back toward the burner instead of towards the boiler.

When the burner shut down the PRV in the pump didn't close tight and oil continued dripping out of the nozzle. Ignited by the hot end cone or shut down the oil dripped backwards in the blast tube burning as it went and out onto the basement floor.

The customer had some trash on the floor, and it caught fire the firomatic at the burner oil pump melted shutting down the oil and saving the house

STEVEusaPA

Well that’s one. I was hoping for a story about one at the tank