Simple plumbing fitting question
 

I have a Myson fan assisted radiator with 3/4" female brass connections
to the heat exchanger. Would it be better to use 3/4" taper fittings
with PTFE or Loctite stuff or 3/4" parallel ones with a fibre washer?
The taper ones make better sense to me, but is there any risk of
splitting the connections if they are as cheap and nasty as most things
are these days?



(By the way, I am seeing 19mm brass threads in the catalogues now - are
they some evil EU standard instead of BSP?)

--

Roger Hayter

Simple plumbing fitting question
 

On 1/10/2017 8:23 PM, Roger Hayter wrote:
I have a Myson fan assisted radiator with 3/4" female brass connections
to the heat exchanger. Would it be better to use 3/4" taper fittings
with PTFE or Loctite stuff or 3/4" parallel ones with a fibre washer?
The taper ones make better sense to me, but is there any risk of
splitting the connections if they are as cheap and nasty as most things
are these days?



(By the way, I am seeing 19mm brass threads in the catalogues now - are
they some evil EU standard instead of BSP?)


Are the Myson fittings terminated with a machined flange, or are they as
forged (not likely)? The presence of a flange implies they should be
fitted with parallel fittings and a fibre washer.

Female taper fittings are shown on this page

https://www.bes.co.uk/products/160.asp#8238

Simple plumbing fitting question
 

newshound wrote:

On 1/10/2017 8:23 PM, Roger Hayter wrote:
I have a Myson fan assisted radiator with 3/4" female brass connections
to the heat exchanger. Would it be better to use 3/4" taper fittings
with PTFE or Loctite stuff or 3/4" parallel ones with a fibre washer?
The taper ones make better sense to me, but is there any risk of
splitting the connections if they are as cheap and nasty as most things
are these days?



(By the way, I am seeing 19mm brass threads in the catalogues now - are
they some evil EU standard instead of BSP?)


Are the Myson fittings terminated with a machined flange, or are they as
forged (not likely)? The presence of a flange implies they should be
fitted with parallel fittings and a fibre washer.

Female taper fittings are shown on this page

https://www.bes.co.uk/products/160.asp#8238


Thanks for the answer, but I'm not totally sure I understand it. The
fittings on the radiator are female, and have no obvious face on them,
although they are fairly flat. In fact, the flats of the hexagon are
within about 1.5mm of the root of the thread, so I doubt a washer would
seal well. I presumably want a male 3/4" fitting, and I am leaning
towards a taper thread one.

--

Roger Hayter

Simple plumbing fitting question
 

On 1/10/2017 9:46 PM, Roger Hayter wrote:
newshound wrote:

On 1/10/2017 8:23 PM, Roger Hayter wrote:
I have a Myson fan assisted radiator with 3/4" female brass connections
to the heat exchanger. Would it be better to use 3/4" taper fittings
with PTFE or Loctite stuff or 3/4" parallel ones with a fibre washer?
The taper ones make better sense to me, but is there any risk of
splitting the connections if they are as cheap and nasty as most things
are these days?



(By the way, I am seeing 19mm brass threads in the catalogues now - are
they some evil EU standard instead of BSP?)


Are the Myson fittings terminated with a machined flange, or are they as
forged (not likely)? The presence of a flange implies they should be
fitted with parallel fittings and a fibre washer.

Female taper fittings are shown on this page

https://www.bes.co.uk/products/160.asp#8238


Thanks for the answer, but I'm not totally sure I understand it. The
fittings on the radiator are female, and have no obvious face on them,
although they are fairly flat. In fact, the flats of the hexagon are
within about 1.5mm of the root of the thread, so I doubt a washer would
seal well. I presumably want a male 3/4" fitting, and I am leaning
towards a taper thread one.

OK if there is no obvious face, then they almost certainly need a taper
fitting. I'm never really happy with PTFE on these, I always use the
Loctite "string" (which replaced the traditional hemp plus boss white).
No other sealant required.

I had a Myson under-unit fan assisted rad years ago but I'm not quite
sure what fittings they had. I "suspect" they had flexible hoses with
push fit at the "copper" end, and male tapers at the "radiator" end.

I am slightly surprised they don't have instructions specifying the
requirements. These days you can usually find the "manual" on the web.

Simple plumbing fitting question
 

On 10/01/2017 20:23, Roger Hayter wrote:
I have a Myson fan assisted radiator with 3/4" female brass connections
to the heat exchanger. Would it be better to use 3/4" taper fittings
with PTFE or Loctite stuff or 3/4" parallel ones with a fibre washer?
The taper ones make better sense to me, but is there any risk of
splitting the connections if they are as cheap and nasty as most things
are these days?



(By the way, I am seeing 19mm brass threads in the catalogues now - are
they some evil EU standard instead of BSP?)


What makes you think they are 3/4" BSP? If they measure around 20mm,
chances are that they are 1/2" BSP.

[With BSP the size relates to the nominal bore of an iron pipe with a
thread on the outside - so if the bore is 1/2", the thread is bigger
than that, and is actually a bit more than 3/4"]

See https://en.wikipedia.org/wiki/British_Standard_Pipe and scroll down
to the size table.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Simple plumbing fitting question
 

newshound wrote:

On 1/10/2017 9:46 PM, Roger Hayter wrote:
newshound wrote:

On 1/10/2017 8:23 PM, Roger Hayter wrote:
I have a Myson fan assisted radiator with 3/4" female brass connections
to the heat exchanger. Would it be better to use 3/4" taper fittings
with PTFE or Loctite stuff or 3/4" parallel ones with a fibre washer?
The taper ones make better sense to me, but is there any risk of
splitting the connections if they are as cheap and nasty as most things
are these days?



(By the way, I am seeing 19mm brass threads in the catalogues now - are
they some evil EU standard instead of BSP?)


Are the Myson fittings terminated with a machined flange, or are they as
forged (not likely)? The presence of a flange implies they should be
fitted with parallel fittings and a fibre washer.

Female taper fittings are shown on this page

https://www.bes.co.uk/products/160.asp#8238


Thanks for the answer, but I'm not totally sure I understand it. The
fittings on the radiator are female, and have no obvious face on them,
although they are fairly flat. In fact, the flats of the hexagon are
within about 1.5mm of the root of the thread, so I doubt a washer would
seal well. I presumably want a male 3/4" fitting, and I am leaning
towards a taper thread one.

OK if there is no obvious face, then they almost certainly need a taper
fitting. I'm never really happy with PTFE on these, I always use the
Loctite "string" (which replaced the traditional hemp plus boss white).
No other sealant required.

I had a Myson under-unit fan assisted rad years ago but I'm not quite
sure what fittings they had. I "suspect" they had flexible hoses with
push fit at the "copper" end, and male tapers at the "radiator" end.

I am slightly surprised they don't have instructions specifying the
requirements. These days you can usually find the "manual" on the web.

The instructions say that they have femal 3/4" fittings and a straight
fitting is preferred (to an elbow presumably, but this is not stated) to
facilitate the routing of the pipes. Nothing about whether the fitting
should be a taper thread. I agree about the Loctite, by the way, it
seems to be very successful. I might have used hemp on 3/4" years ago,
it's about on the borderline. I think PTFE tape works ok on 1/2".


What is this 19mm thread, do you know?




--

Roger Hayter

Simple plumbing fitting question
 

Roger Mills wrote:

On 10/01/2017 20:23, Roger Hayter wrote:
I have a Myson fan assisted radiator with 3/4" female brass connections
to the heat exchanger. Would it be better to use 3/4" taper fittings
with PTFE or Loctite stuff or 3/4" parallel ones with a fibre washer?
The taper ones make better sense to me, but is there any risk of
splitting the connections if they are as cheap and nasty as most things
are these days?



(By the way, I am seeing 19mm brass threads in the catalogues now - are
they some evil EU standard instead of BSP?)


What makes you think they are 3/4" BSP? If they measure around 20mm,
chances are that they are 1/2" BSP.

[With BSP the size relates to the nominal bore of an iron pipe with a
thread on the outside - so if the bore is 1/2", the thread is bigger
than that, and is actually a bit more than 3/4"]

See https://en.wikipedia.org/wiki/British_Standard_Pipe and scroll down
to the size table.

The fact that they are considerably bigger than 1/2" BSP (combined with
the rarity of 5/8" BSP) and that the fitting instructions for the
equipment state that they are 3/4" BSP combine to convince me. To the
extent I haven't bothered to measure them! The way the thing is packed
(and I have to send it back as it is broken) make it somewhat difficult
to measure anyway.
--

Roger Hayter

Simple plumbing fitting question
 

Roger Hayter wrote:

Roger Mills wrote:

On 10/01/2017 20:23, Roger Hayter wrote:
I have a Myson fan assisted radiator with 3/4" female brass connections
to the heat exchanger. Would it be better to use 3/4" taper fittings
with PTFE or Loctite stuff or 3/4" parallel ones with a fibre washer?
The taper ones make better sense to me, but is there any risk of
splitting the connections if they are as cheap and nasty as most things
are these days?



(By the way, I am seeing 19mm brass threads in the catalogues now - are
they some evil EU standard instead of BSP?)


What makes you think they are 3/4" BSP? If they measure around 20mm,
chances are that they are 1/2" BSP.

[With BSP the size relates to the nominal bore of an iron pipe with a
thread on the outside - so if the bore is 1/2", the thread is bigger
than that, and is actually a bit more than 3/4"]

See https://en.wikipedia.org/wiki/British_Standard_Pipe and scroll down
to the size table.

The fact that they are considerably bigger than 1/2" BSP (combined with
the rarity of 5/8" BSP) and that the fitting instructions for the
equipment state that they are 3/4" BSP combine to convince me. To the
extent I haven't bothered to measure them! The way the thing is packed
(and I have to send it back as it is broken) make it somewhat difficult
to measure anyway.

By the way, this is what I mean by 19mm:

http://www.screwfix.com/p/pegler-px4...2-x-19mm/5411g


It looks like 3/4" BSP, but that would be about 25mm, and not a standard
metric thread. Is this just some misconceived naming, or do they
translate the names of BSP threads when they use them on the Continent?




--

Roger Hayter

Simple plumbing fitting question
 

On 10/01/17 23:32, Roger Hayter wrote:
snip


By the way, this is what I mean by 19mm:

http://www.screwfix.com/p/pegler-px4...2-x-19mm/5411g


It looks like 3/4" BSP, but that would be about 25mm, and not a standard
metric thread. Is this just some misconceived naming, or do they
translate the names of BSP threads when they use them on the Continent?


I think it's Screwfix who employ the rogue translater: Pegler themselves
seem to describe the PX46 as "elbow, copper x female iron", and one of
them is 22mm x 3/4". No mention of female iron in mm dimensions.

--
Kevin

Simple plumbing fitting question
 

Kevin wrote:

On 10/01/17 23:32, Roger Hayter wrote:
snip


By the way, this is what I mean by 19mm:

http://www.screwfix.com/p/pegler-px4...2-x-19mm/5411g


It looks like 3/4" BSP, but that would be about 25mm, and not a standard
metric thread. Is this just some misconceived naming, or do they
translate the names of BSP threads when they use them on the Continent?


I think it's Screwfix who employ the rogue translater: Pegler themselves
seem to describe the PX46 as "elbow, copper x female iron", and one of
them is 22mm x 3/4". No mention of female iron in mm dimensions.

That's reassuring. I thought I was unaware of something important.
No-one seen the same thing elsewhere?

--

Roger Hayter

Simple plumbing fitting question
 

On 11/01/2017 10:54, Roger Hayter wrote:
wrote:

On 10/01/17 23:32, Roger Hayter wrote:
snip


By the way, this is what I mean by 19mm:

http://www.screwfix.com/p/pegler-px4...2-x-19mm/5411g


It looks like 3/4" BSP, but that would be about 25mm, and not a standard
metric thread. Is this just some misconceived naming, or do they
translate the names of BSP threads when they use them on the Continent?


I think it's Screwfix who employ the rogue translater: Pegler themselves
seem to describe the PX46 as "elbow, copper x female iron", and one of
them is 22mm x 3/4". No mention of female iron in mm dimensions.

That's reassuring. I thought I was unaware of something important.
No-one seen the same thing elsewhere?


No, it's a strange way of representing it. 19mm is pretty close to 3/4",
so this is almost certainly referring to the nominal bore rather than to
the thread. If you scroll down the SF page which you cite, you'll see
that it specifies the thread size as 3/4" - which I take to mean 3/4" BSP.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

Simple plumbing fitting question
 

On 10/01/2017 22:53, Roger Hayter wrote:


The instructions say that they have femal 3/4" fittings and a straight
fitting is preferred (to an elbow presumably, but this is not stated) to
facilitate the routing of the pipes. Nothing about whether the fitting
should be a taper thread. I agree about the Loctite, by the way, it
seems to be very successful. I might have used hemp on 3/4" years ago,
it's about on the borderline. I think PTFE tape works ok on 1/2".

If your rad has brass female fittings, then you probably don't want
to screw a tapered male into it because you may just crack the
female fitting. Therefore locktite, fernox lsx or a fibre
washer is the only solution.

Simple plumbing fitting question
 

Andrew wrote:

On 10/01/2017 22:53, Roger Hayter wrote:


The instructions say that they have femal 3/4" fittings and a straight
fitting is preferred (to an elbow presumably, but this is not stated) to
facilitate the routing of the pipes. Nothing about whether the fitting
should be a taper thread. I agree about the Loctite, by the way, it
seems to be very successful. I might have used hemp on 3/4" years ago,
it's about on the borderline. I think PTFE tape works ok on 1/2".

If your rad has brass female fittings, then you probably don't want
to screw a tapered male into it because you may just crack the
female fitting. Therefore locktite, fernox lsx or a fibre
washer is the only solution.

That was my concern! Thanks for the comment. I don't think the
Loctite thready stuff is recommended other than for tight taper threads,
and I have found it does need to be tight. There is no convincing seat
for a fibre washer on the female fitting. How would the Fernox LSX be
used, a parallet thread or not very tight taper thread? And does it
need any inert filler like hemp or similar? Does it need any particular
physical or chemical thread preparation?

Thanks in advance,



--

Roger Hayter

Simple plumbing fitting question
 

Roger Hayter wrote:

Andrew wrote:

On 10/01/2017 22:53, Roger Hayter wrote:


The instructions say that they have femal 3/4" fittings and a straight
fitting is preferred (to an elbow presumably, but this is not stated) to
facilitate the routing of the pipes. Nothing about whether the fitting
should be a taper thread. I agree about the Loctite, by the way, it
seems to be very successful. I might have used hemp on 3/4" years ago,
it's about on the borderline. I think PTFE tape works ok on 1/2".

If your rad has brass female fittings, then you probably don't want
to screw a tapered male into it because you may just crack the
female fitting. Therefore locktite, fernox lsx or a fibre
washer is the only solution.

That was my concern! Thanks for the comment. I don't think the
Loctite thready stuff is recommended other than for tight taper threads,
and I have found it does need to be tight. There is no convincing seat
for a fibre washer on the female fitting. How would the Fernox LSX be
used, a parallet thread or not very tight taper thread? And does it
need any inert filler like hemp or similar? Does it need any particular
physical or chemical thread preparation?

Thanks in advance,

Can I beg for further advice/opinion? Is there actually any way of
reliably making a leakproof joint between parallel threads in the
absence of any provision for a washer or 'o' ring?

--

Roger Hayter

Simple plumbing fitting question
 

"Roger Hayter" wrote in message
...
Roger Hayter wrote:

Andrew wrote:

On 10/01/2017 22:53, Roger Hayter wrote:


The instructions say that they have femal 3/4" fittings and a
straight
fitting is preferred (to an elbow presumably, but this is not stated)
to
facilitate the routing of the pipes. Nothing about whether the
fitting
should be a taper thread. I agree about the Loctite, by the way, it
seems to be very successful. I might have used hemp on 3/4" years
ago,
it's about on the borderline. I think PTFE tape works ok on 1/2".

If your rad has brass female fittings, then you probably don't want
to screw a tapered male into it because you may just crack the
female fitting. Therefore locktite, fernox lsx or a fibre
washer is the only solution.

That was my concern! Thanks for the comment. I don't think the
Loctite thready stuff is recommended other than for tight taper threads,
and I have found it does need to be tight. There is no convincing seat
for a fibre washer on the female fitting. How would the Fernox LSX be
used, a parallet thread or not very tight taper thread? And does it
need any inert filler like hemp or similar? Does it need any particular
physical or chemical thread preparation?

Thanks in advance,

Can I beg for further advice/opinion? Is there actually any way of
reliably making a leakproof joint between parallel threads in the
absence of any provision for a washer or 'o' ring?

Yep, ptfe tape works fine.

Simple plumbing fitting question
 

On Thursday, 12 January 2017 21:24:40 UTC, Rod Speed wrote:
"Roger Hayter" wrote in message
...

Can I beg for further advice/opinion? Is there actually any way of
reliably making a leakproof joint between parallel threads in the
absence of any provision for a washer or 'o' ring?

Yep, ptfe tape works fine.

or linseed putty.


NT