Riser Seal Replacement - G90 & G95 Risers - Hunter G835 Owner's Manual

RiSeR SeAl RePlACeMenT – g90 And g95 RiSeRS
the g90 and g95 riser seal assembly and the compressed retraction spring are retained on the riser with the retainer
cap (plastic plate) at the top of the riser assembly. It is necessary to remove the retainer cap in order to replace the
riser seal components. to remove the retainer cap, fully compress the riser spring by grabbing the riser seal assembly
(fig 51), pressing downward and then holding riser firmly to prevent the spring from moving upwards.
Caution! The riser assembly is under spring tension. Eye protection should be worn and safe-handling
procedures followed when servicing this product.
Hold the riser seal assembly down with one hand. locate the two screws that hold the retainer cap to the riser
assembly (fig 52). use a phillips screwdriver to engage each retaining screw and turn counter-clockwise to remove.
prior to removing the g90 or g95 retainer cap, note its orientation as it relates to the nozzles below. this will help
with the assembly process later. remove the retainer cap and set aside.
While still holding the compressed riser seal assembly and retraction spring with one hand, use the other hand
to grasp the bottom of the riser assembly. slowly release the compression of the retraction spring until it is fully
extended and no pressure is felt. note the orientation of the riser components to help with assembly later (fig 53).
the riser seal on g90 and g95 risers include two primary components - the seal block assembly and the face-seal.
the seal block assembly sits on top of the retraction spring and has two sealing surfaces. First, the seal block has
an o-ring around the outside. If the o-ring is damaged, deteriorated or missing, the riser will leak water while the
sprinkler is operating. the second sealing surface on the seal-block assembly is on the underside. the angled
surface on the underside of the seal-block assembly is the interface for the face-seal. If this angled interface surface
is cut or otherwise damaged, the riser can leak water during sprinkler operation. the face-seal is the second primary
component to the g90 and g95 riser seal design. the face-seal is the white plastic angled ring that is position at the
base of the riser. If the face-seal is damaged, deteriorated or missing, the riser will leak during sprinkler operation.
If the riser is leaking during sprinkler operation, the o-ring, the interface and the face-seal must be inspected in
order to determine the cause of the leakage. If the o-ring is damaged, it can easily be replaced by removing the
damaged o-ring from the seal-block and replacing it with a new one. use care to ensure that the o-ring is not cut or
twisted during the installation process. If the interface is damaged, the entire seal-block must be replaced. also, if the
interface is damaged it is highly likely that the face-seal is damaged as well and needs replacement.
to replace the face-seal, slide it upwards and off the riser assembly. replacement face-seals must fit very snug to
the stainless-steel on the riser. as a result, there may be considerable resistance when attempting to install the new
face-seal. to make installation easier, the face-seal's diameter can be expanded by placing it in the sun for several
minutes. or, if the repair is being done in the shop, placing the face-seal in warm water for several minutes will
cause expansion as well. slide the new face-seal down and onto the riser. Make sure that it is pressed all the way
until it is seated firmly against the ledge at the base of the riser. Install the retraction spring and seal-block assembly
onto the riser. press down on the seal-block to compress the retraction spring and hold firmly in this position. While
firmly holding the retraction spring and seal assembly down, place the retainer cap on top of the riser in the correct
orientation. Insert the two stainless-steel screws and hand-tighten with a phillips screwdriver.
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Fig 51
FIg 51
Fig 51
Fig 51
Fig 52
FIg 52
Fig 52
Fig 52
FIg 53