Lochinvar HS 50 Series 100, User'S Information Manual

27

completely reset and continues to release water, immediately close 
the cold water inlet to the heat pump, follow the draining 
instructions in the storage tank manual, and replace the 
temperature-pressure relief valve with a properly rated/sized 
new one.

If you do not understand these instructions or have any questions 
regarding the temperature-pressure relief valve call the toll 
free number listed on the back cover of this manual for technical 
assistance.

CLEANING INTERNAL INSULATION

Inspect the internal insulation on a yearly basis for any microbial 
growth. The insulation never has to be cleaned unless microbial 
growth is detected. If microbial growth is detected, follow the 
removal steps below:

1.  Disconnect all power to the unit and follow the prescribed 

lock-out/tag-out procedure.

2.  Wear the prescribed personal protective equipment 

prescribed from the cleaning product instructions.

3.  Remove as much dirt and organic material from the insu-

lation using a vacuum device with a HEPA fi lter (99.97% 
effi

  cient at 0.3 micron particles). Be careful not to tear the 

insulation during the cleaning procedure.

4.  Apply the microbial cleaning agent as prescribed by the 

application and usage instructions.

5.  Allow the unit to dry thoroughly.

6.  If necessary, apply an anti-microbial agent on the insulation 

per the instructions provided on the product label.

Discard collected microbial contaminants as required by local 
or state codes.

CHECKING  REFRIGERANT CHARGE

Servicing of the refrigeration circuit must only be performed 
by agencies or individuals possessing Type II or Universal 
certification as defi ned in Section 608 of the Clean Air Act. 
See Qualifi cations on page 3.

This HPWH unit is factory charged with 134a refrigerant. See 
the rating label on the HPWH unit and Table 9 for refrigerant 
charge by weight. It should not be necessary to add or 
remove refrigerant during installation or start up. Refrigerant 
lost during frequent refrigerant pressure testing can cause 
low refrigerant conditions. Air and water fl ow should always 
be checked fi rst to eliminate other potential problems before 
checking the refrigerant charge. 

CHECK WATER TEMPERATURE RISE

Always check water temperature rise through the HPWH 
unit’s internal heat exchanger before checking the refrigerant 
charge. See Start Up on page 19 for information on how to 

measure the water temperature rise.

If the measured water temperature rise during start up was 
within 8°F to 12°F (4°C to 7°C) checking the charge is not 
necessary unless other conditions warrant testing.

If the measured temperature rise through the HPWH unit is 
less than 8°F (4°C) checking the charge is not necessary 
unless other conditions warrant testing. Short water piping 
runs between the HPWH and the storage tank will produce 
lower temperature rises and are not problematic.

If the measured temperature rise through the HPWH unit is 
more than 12°F (7°C) check for restrictions in the inlet and outlet 
water piping connected between the HPWH unit and the storage 
tank.

TABLE 9

SUPERHEAT CALCULATION

1.  Measure and record the suction pressure at the 

suction line pressure access port inside the unit.

2.  Convert the recorded suction pressure to saturated 

temperature.

3.  Measure the suction line temperature near the suction 

line pressure access port inside the unit.

4.  Compare the suction line temperature to the saturated 

temperature in Table 10 on the next page.

5. The di

ff

 erence between saturated temperature and 

suction line temperature is the superheat. Superheat 
normal range should be 8°F to 12°F (4.4°C to 6.7°C)

BRAZE PLATE CLEANING INSTRUCTIONS

In some applications the heat exchanger may be subjected 
to severe fl uid conditions, including high temperature hard 
water conditions, causing accelerated scaling and corrosion 
rates, and will diminish performance.

It is important to establish regular cleaning schedules, A 5% 
solution of Phosphoric Acid or Oxalic Acid may be considered. 
Other types of solutions can be obtained from your local 
wholesaler. Make sure cleaning solution is applicable for stainless 
steel and copper and all directions are followed.

Do not heat solution. Be sure to fl ush heat exchanger with 
fresh water after cleaning. See Figure 12 on the next page.

Model

Factory Charge R134A

WHP025

7 #

WHP060

14 #

WHP090

21 #

WHP125

25 #

WHP185

30 #

WHP250

50 #