Forespar Flowtech Flush-Mount Valves — Installation Instructions

Usage

A plunger moves up or down: up lets water flow into the boat; down and locked leaves a perfectly smooth hull surface. A pair of O-rings seals the plunger when closed and locked.

1. To unlock, flip the valve handle up and over so the red dot faces upwards.
2. Pull the plunger up (open) or push it down towards the hull (closed). Then lock it by flipping the handle over so the green dot faces upwards.

Always leave the valve locked, open or closed, so the plunger cannot change position unexpectedly.

Dimensions (D101)

The installation sheets give a 1-7/8" (48 mm) hull hole and a minimum 5/8" bury (hull thickness) for both #905106 and #905109; the D101 drawing lists a larger bury diameter for the Mark 2 (as printed). Check your valve before drilling.

Installation

Forespar recommends installation by a qualified professional or certified marine technician familiar with boat plumbing.

1. Choose a location with room for full operation of the valve and for routing hoses.
2. Drill a 1-7/8" (48 mm) hole through the hull in a reasonably flat internal surface. The hull must be at least 5/8" thick; if not, build a backing block (waterproofed plywood covered with at least two layers of laminated fiberglass cloth). The bury can be in the backing block.
3. On a cored or multilayer hull, thoroughly apply resin inside the hole to isolate the core.
4. With the valve closed and locked, clean the bonding surfaces with acetone or another strong non-petroleum cleaner; let the acetone fully evaporate (it can damage the O-rings).
5. Prepare a thick bedding compound (Cabosil or similar thickener with polyester, vinylester or epoxy resin suitable for your hull), or a marine sealant. Work it into the hole and the outside ribs of the valve.
6. Insert the valve so a little compound squeezes out from under the flange. Do not press hard enough to flex the flange – it would leave voids when it springs back.
7. When cured, bond the flange to the hull with 17 oz. woven glass: circles with 1-7/8" centre holes, each larger than the last, laminated concentrically smallest first, the last one extending at least 3" beyond the flange. The main sheet calls for at least three layers; the F120 sheet for four or five laminations of 17 oz. E-glass in the hull lay-up resin.
8. When all resins are cured, with the valve down and locked, saw off the bulk of the protruding valve (protect the hull with tape) and grind it flush. F120: disk off a minimum of 1/2" to a smooth flush surface, so the piston opens fully and does not partially block the exit port.
9. Paint the area like the rest of the hull. The bottom of the plunger can be painted in the down position – do not apply so much paint around it that it cannot break loose.

Maintenance

• Operate the valves regularly: operation draws lubricant around the shaft seals. Lack of use or drying out makes the piston stiff.
• Use ONLY silicone grease or Marelube, on the shaft only.
• Do NOT use aerosols, petroleum-based lubricants or WD-40 (they damage the O-rings). Do NOT lubricate the O-rings.