THE ECU UNIT
Operating and Service Instructions
Model HR06
Operations Check:
1. To determine if the ECU Is functioning, allow the air conditioning system to operate some ten minutes or
more, Then go to the water tank location, and identify the line entering the water tank from the ECU unit.
Grasp this line with the bare hand, as far away from the tank as possible. In normal installations, this line
will be warmer than the line going to the ECU. If it is not, read the service notes below, and if the problem is
not solved, call your dealer.
2. To determine if the ECU is producing hot water, pick one week of warm summer weather, and put the water
heater breaker on "off." In an average residential installation there should be ample water for all concerned.
Water tank capacity, and use patterns must be considered. The ECU produces hot water during air
conditioning operating time only; high use at night could exhaust the tank and minimum A/C run time at
night would not replenish the tank even though the ECU was producing normally.
Service Notes:
1. No circulation in the ECU water lines:
a. Pump Failure. Open ECU cabinet and visually verify ECU pump operation while air conditioning
system is operating.
b. Air Lock. Any time the residential water system is serviced, or any time the supply mains are
serviced, air may enter the ECU water circuit, and an air pocket in the system will disable it
completely, though without damage. Manually open the temperature and pressure relief valve at the
water tank, and try to bleed the air from the system. It the output from the relief valve contains air,
continue the bleed operation until a solid flow of water is observed.
c. If this measure does not solve the problem, check for mechanical damage to the lines.
d. If this check does not provide a solution, call your dealer, and ask for a serviceman to give the
installation a complete technical check.
2. If the ECU is circulating, but the production is below normal, there are two possibilities.
a. If the unit is three or more years old, mineral buildup may occur in the heat exchanger in some areas
of hard water or well water. If this problem is suspected, call your serviceman, and he will flush the
heat exchanger with an approved solvent that will dissolve the deposits and restore the heat
exchanger to the same performance as when new
b. If the heat exchanger is clear, the most probable cause of low ECU performance is a malfunction in
the air conditioning system itself. Any condition lowering the net load and decreasing the superheat
will reduce ECU performance. Typical of these are dirt clogged evaporators, clogged filters, slipping
belts
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on the blower and many others. This type of problem may only be solved by a competent air
conditioning technician.
3. Freeze
Protection:
a. Model numbers with "F" (Freeze) designation protect the heat recovery system during freeze
conditions. It also allows ECU units to operate either from a power disconnect or the line side of the
A/C contactor and must be checked by a certified A/C technician only.
WARNING:
This important notice must be given to the homeowner if this heat recovery system is installed outside. The
potential for water lines freezing and rupturing exists. Even though the ECU may be equipped with freeze
protection devices, they will be useless if electric power is off. Isolate the outside water lines and drain the water
from the system. Disconnect the power to the pump.
DO NOT RUN THE PUMP WITHOUT WATER!
