Hoshizaki 73180 User Manual

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As ice melts, water drains from the storage bin into DP. When DP's LF/S closes, DP 
energizes and pumps out the water. If water cannot be pumped out of DP due to a 
blocked discharge hose, bad check valve, or bad DP motor, the water level rises and 
UF/S closes. When UF/S closes, DP safety activates and unit shuts down. DP safety 
interrupts power to icemaker components until UF/S opens. Power is supplied to DP 
motor as long as LF/S is closed. 
For schematics, see "III.B.2. Icemaker with Optional Drain Pump HS-0248."

• If you remove DP from the icemaker and/or remove the reservoir cover, be sure to 

follow all instructions below. Failure to do so may result in costly water damage.

• DP has an external or internal check valve. If DP contains an internal check valve, 

do not install an external check valve and vice versa. See Fig. 6.

Legend: 

DP–drain pump; LF/S–lower float switch; UF/S–upper float switch

If the optional DP (HS-0248) is installed, test its operation at least twice a year as 
outlined below. Note that DP has power even when the power switch is in the "OFF" 
position.

If DP is not primed or is otherwise not operating properly, it will adversely affect 
performance, component life, and warranty coverage and may result in costly water 
damage. 

1) Move the power switch to the "OFF" position, then unplug the unit from the electrical 

outlet. 

WARNING! To reduce the risk of electric shock, do not touch the power 

2) Remove all ice from the storage bin.
3) Plug the unit back in.
4) Slowly pour 16 to 24 oz. (500 to 750 ml) of water over the storage bin drain hole in the 

storage bin.

External Check Valve

Internal Check Valve