Hello all--
based on prior discussions 'round here about how modern-made expansion tanks seem shorter-lived than the ones in past decades, but that the solar-rated ones seem to be longer-lived, even though more expensive, I picked up a Caleffi/ Zilmet solar-rated 18 liter tank from Houseneeds.com, which is about a half hour from me
(I should say, too, that Houseneeds in general, especially Gil there in sales, were very patient and helpful with me and that they stock a lot of interesting stuff like Caleffi, Laing DC pumps, and other things that are still a bit off the beaten track in much of the US plumbing industry).
but tonight as I was doing some more preliminary layout and trial fit-up of parts of my system, I found that the Caleffi tank has a male thread that _looks_ a whole lot like a male 3/4 NPT, but won't seem to thread into a female NPT beyond the first 2/3 of a turn. On closer examination, it looks like a straight-taper thread, not the taper that goes with the norm of NPT. The instructions and specs, printed in a panoply of languages, say nothing about the thread type or size.
part # is Caleffi Solar 259018
and it's described here-
(broken link removed)
now that I bumped into this "issue," I do see that they describe it as "3/4 inch straight thread connection" When I read that before, I thought that they meant straight as in "not elbow" but now I am scratching my head in thinking that they meant "non-tapered"
I am most familiar with NPT, but have heard of BPT, Whitworth, AN/ O-ring, and what not, although I forget a lot of the distinctions. I'm not too familiar with any un-tapered pipe thread.
Anyone know if the pitch of this is likely the same as NPT so that I might find a friendly person with a 3/4 NPT die to re-cut it to a taper thread without mangling it?
Can anyone shed any light on what thread this critter has and how to adapt it, or, if I have to return it if it is too complicated to make it fit, other makes and sources of solar-rated expansion tanks that won't send me to the poorhouse? I am going to try to contact Houseneeds and maybe Caleffi tomorrow, but knowing the reservoir of knowledge here, if someone else can clue me in first, that'll save me some wild-goose chasing.
while I am asking annoying questions, is an 18 liter/ 5 gallon tank hopefully in line with a 32 gallon boiler and a compact/ not-too-high-volume primary/ secondary system? I've been sweating so many other details that I decided to take a knowing careless fly-er on the sizing of the expansion tank, but now that it looks like I may need to hack with it in a way that'd make it non-returnable, I'd rather return it sooner rather than later if I really need something bigger
Thanks, as always
based on prior discussions 'round here about how modern-made expansion tanks seem shorter-lived than the ones in past decades, but that the solar-rated ones seem to be longer-lived, even though more expensive, I picked up a Caleffi/ Zilmet solar-rated 18 liter tank from Houseneeds.com, which is about a half hour from me
(I should say, too, that Houseneeds in general, especially Gil there in sales, were very patient and helpful with me and that they stock a lot of interesting stuff like Caleffi, Laing DC pumps, and other things that are still a bit off the beaten track in much of the US plumbing industry).
but tonight as I was doing some more preliminary layout and trial fit-up of parts of my system, I found that the Caleffi tank has a male thread that _looks_ a whole lot like a male 3/4 NPT, but won't seem to thread into a female NPT beyond the first 2/3 of a turn. On closer examination, it looks like a straight-taper thread, not the taper that goes with the norm of NPT. The instructions and specs, printed in a panoply of languages, say nothing about the thread type or size.
part # is Caleffi Solar 259018
and it's described here-
(broken link removed)
now that I bumped into this "issue," I do see that they describe it as "3/4 inch straight thread connection" When I read that before, I thought that they meant straight as in "not elbow" but now I am scratching my head in thinking that they meant "non-tapered"
I am most familiar with NPT, but have heard of BPT, Whitworth, AN/ O-ring, and what not, although I forget a lot of the distinctions. I'm not too familiar with any un-tapered pipe thread.
Anyone know if the pitch of this is likely the same as NPT so that I might find a friendly person with a 3/4 NPT die to re-cut it to a taper thread without mangling it?
Can anyone shed any light on what thread this critter has and how to adapt it, or, if I have to return it if it is too complicated to make it fit, other makes and sources of solar-rated expansion tanks that won't send me to the poorhouse? I am going to try to contact Houseneeds and maybe Caleffi tomorrow, but knowing the reservoir of knowledge here, if someone else can clue me in first, that'll save me some wild-goose chasing.
while I am asking annoying questions, is an 18 liter/ 5 gallon tank hopefully in line with a 32 gallon boiler and a compact/ not-too-high-volume primary/ secondary system? I've been sweating so many other details that I decided to take a knowing careless fly-er on the sizing of the expansion tank, but now that it looks like I may need to hack with it in a way that'd make it non-returnable, I'd rather return it sooner rather than later if I really need something bigger
Thanks, as always
