N.Design Studio

Pond heating

90 degree threaded elbows
90<sup>o</sup>elbow (plain/threaded) In most cases the heat exchanger needs to be fitted in a small area and so the bends need to be as sharp as possible.
In this case 90 degree elbows were used and they were plain/BSP threaded. As the connections on this heat exchanger are 2.0 inch BSP it ensures that the tightest bend possible was used, and without these the pressure/expansion vessel could not have been fitted on this wall.

   
TIP. These type of fittings are not usually available at your normal pipe supplier as they seem to be rarely used. They also will not order them unless you are willing to buy a box of 10. Some of the larger koi suppliers in the UK can supply them so this should be planned well in advance so that they are available when you want them.
Plain/BSP female thread An alternative method is to use this adapter. It has a plain spigot and BSP female thread.
This can be used with a plain 90 degree elbow, but the pipe centreline will be further away from the heat exchanger than with the type shown above. If you have sufficient room then this adapter could be used with a 90 degree bend which will give a smoother flow than when using an elbow.
These fittings are probably almost as difficult to purchase as the one shown above.
Plain/BSP threaded socket This is a plain/BSP threaded socket and should be available from most suppliers.
With the use of a very short length of pipe then a plain elbow or bend can be used. The disadvantage is that the distance from the pipe centreline to the heat exchanger will be longer by the width of the socket compared with the plain/BSP threaded elbow shown at the top of the page.
Plain/BSP threaded socketPlain/BSP threaded socket
The photo on the left shows the 2.0 inch threaded/plain elbow used in this installation, and this is the tightest bend you can get with these pipe fittings.
The photo on the right shows an adapter as described above in the second paragraph . It has a plain spigot and BSP female thread, and in this case 1.5 inch pipe has been used. The elbow is 1.375 inches further away than if a threaded elbow had been used.

TIP. The thread on the heat exchangers are not tapered threads and there can be problems with getting the connection to the elbow watertight. This can usually be solved by using a large amount of pvc thread tape, or you can use silicon. If you do use silicon then make sure that it is suitable for use with fish.