Maintenance
1.
After use, flush the pump with clean water.
2. Hypro diaphragm pumps come with oil in the
crankcase.
Hypro recommends changing oil after
40 hours of break-in operation and every three
months or 500 hours, whichever comes first. Use
Hypro Oil (Part Number 2160-0038)
. Hypro Oil is a
specially formulated, high-grade, nondetergent, SAE
30 weight oil designed to prolong pump life.
To drain oil from the pump, remove the oil drain plug,
and rotate the shaft until the oil stops flowing out. To
fill the pump with oil, slowly pour the oil into sight
tube while turning the pump shaft. Turning the pump
shaft purges all the air out of the crankcase. Always
change oil when replacing diaphragms.
3. For winter storage or if a freezing condition will be
encountered, flush pump with a 50/50 mixture of
water and antifreeze.
Figure 1. Diaphragm Replacement
Diaphragm and Valve Replacement
I. Valve and O-Ring Replacement
1. Occasionally debris can cause the valves to not
seat properly or damage the o-rings. To check
for this problem, follow these steps.
2. Remove the pump manifold. (See parts list for
your model.) Use a 17 mm box wrench (or
adjustable wrench) to remove manifold nuts.
(Use a 13 mm for Models D160, D250.) With
manifold removed, valves can readily be
removed and checked for debris or wear. To
replace valves or o-rings, refer to parts list for
appropriate kits.
II. Diaphragm Replacement
Hypro recommends changing diaphragms every 500
hours or three months, whichever comes first.
1. Drain the oil from the pump by removing drain
plug. Rotate the shaft to remove excess oil.
2. Remove the pump manifold according to Step 2
in Section I: Valve and O-ring Replacement.
3. Use a 19 mm box wrench (or adjustable wrench)
to remove the diaphragm retaining bolt, support
washer and diaphragm. To replace the
diaphragms, order the appropriate repair kit.
See the parts list.
4. Turn the crankshaft to bring the piston to its
upstroke to replace the diaphragm. Use the
downstroke to seat the new diaphragm into the
sleeve groove. Install retaining washer and
tighten nut.
5. Replace the pulsation dampener diaphragm by
first bleeding the air from the dampener. (See
parts list for your model.) Use a 13 mm box
wrench to remove the bolts holding the
dampener assembly together, then replace
diaphragm. Recharge dampener to 20% of
operation pressure.
6. Refill crankcase with Hypro Oil (Part No. 2160-
0038). Rotate the shaft slowly forward and
reverse to distribute oil, and fill to the proper
level.
4
Maintenance Instructions for All Models
Bolt
Washer
Diaphragm
L-1381 (Rev. B)
