question about swing joint elbow orientation on a Roth tank

mrblint

We are getting a new Roth tank to replace our old 1950s-era tank. The new vent and supply pipes will enter through the exterior wall via the same holes. That location will have the piping on the opposite side of the tank than is shown in the attached sketch from the Roth manual.

According to the Roth installation instructions, the swing joint is to allow some vertical movement in the piping since the tank can lower by as much as 1/4 inch when filled, which can cause a gap at the gaskets at the connectors and allow oil fumes to enter the living space.

The attached picture shows how the elbow on the pitched supply and vent lines can loosen on the pitched pipes if the weight of the oil pulls the tank downward. But what if the pitched pipes have to enter above the tank along its left hand side and then turn in the opposite direction towards the connectors? Downward movement would cause the elbows to tighten on the pitched pipes if it is a simple two-elbow joint.

Do the elbows always have to be oriented so that downward movement of the tank loosens the elbows on the pitched vent and supply pipes that come in through the wall? Is a third elbow required in that case?

Roth Swing Joint assembly.png

mrblint

P.S. Just in case my description wasn't clear…. the sketch shows the pipes entering on the "h" side of the "Roth" label and turning towards the "R". Our pipes will enter above the "R" side and the elbow will turn towards the "h".

Big Ed_4

What matters is the pitch of the pipes back to the tank for drainage . I am sure Roth also wants to relive the stress of the pipe work against the Roth plastic adapters . Using a second elbow breaks the rigidness of the run of pipe . Using a swing joint will also make the task of catching the start thread easier . It will allow adjustment of the fitting and pipe to connect the two ..

Hope this helps

mrblint

https://forum.heatinghelp.com/discussion/comment/1857086#Comment_1857086

Pitch too, but they explicitly call out the need to check that a gap at the gasket hasn't been created by the weight of the first full fill, and say that the tank can get lower by as much as 1/4 inch with the weight of the oil. I was wondering if the elbow attached to the pitched pipes must always be oriented so it moves in the loosening direction to handle downward motion of the tank, or if an installer could simply install that elbow somewhat loose, so it could move in either the tightening or loosening direction.

EBEBRATT-Ed

Use a 3 elbow swing. Have the pipe come in past the centerline of the tapping put a 90 on the pipe then a nipple and another 90 then a nipple and a 90 down into the tank. So you come in past the centerline turn then turn and go back to the tapping. I would arrange the fittings so they tighten when the tank is filled.

I am not sure Roth knows what they want.

If the tank settles as it is filled and they are worried about a gap why do they have pipe hangers shown in the diagram??

Seems to me the pipes need to be unsupported so they will float with the tank or you will have a gap. Swing joints can't swing when hung.

Common sense must prevail. Just hook it up

Big Ed_4

I think he is talking about the rubber gasket under the plastic adapter . I snug up on the adapter first before running the iron out .. The pipe should come in straight into the adapter so it sits flat and seal the connection … The swing joint gives you the ability to adjust the iron pipe to be connected at the proper angle .