Enertech Global
24
EAV - EME/EMD Rev. A Models
Installation and Operations Manual
System Pump:
System should include a variable speed (Delta-T
or Delta-P control) or constant speed pump to provide flow
from the hydraulic separator to the hydronic zones. A pressure
differential bypass valve must be installed to avoid dead heading
the pump if zone valves are not fully open.
Strainer:
A strainer is included in the Indoor Module. It must be
checked and cleaned as necessary to ensure proper flow rate
and long-term unit reliability.
Unions, Adapters, Misc Fittings:
All necessary unions, adapters
and fittings should be installed to allow ease of service and to
meet any local code requirements.
Components Needed for Enertech Recommendations
The Systems Accessories Table (Section 6) includes a reference
when ordering a new system to determine which items
are included with the unit, which items must be purchased
separately, and which items must be purchased locally from a
plumbing wholesaler.
Designing the System
Section 6 provides guidelines for pump mounting, flow rate
requirements, pipe sizing, and flushing/purging the system.
Section 8 has control options that work with the piping diagrams
in Section 6 (see “Wiring Diagram Selection Chart” for control
selection). Enertech strongly recommends using an approved
zone control (Hydro-Connect or EWC) to provide the most
compatible operation with the Indoor Module. Although other
control systems will work, Enertech Technical Services personnel
are most familiar with the approved controls. Other controls may
be difficult to support should troubleshooting be needed.
DHW Considerations
According to the Water Research Foundation, the average
American shower uses approximately 15.8 gallons and lasts for
7.8 minutes at an average flow rate of 2.1 gpm. Depending upon
local regulations, shower heads may be available with 1.8, 2.0,
or 2.5 gpm flow rates. The state of California, for example limits
the flow rate to 1.8 gpm, as of July 2018. In some cases flow
restrictors can be removed/modified or multiple shower heads
may allow significantly more water usage.
Following are some considerations when determining indirect
water heater choice, as well as the need for a second water
heater:
EAV Capacity:
The EAV unit has much higher capacity than a
standard electric or gas water heater, although the indirect water
heater storage is for “load water”, not potable water. Therefore,
the Turbomax indirect water heater operates more like an
instantaneous water heater than a standard water heater. Based
upon Enertech lab testing, draws of 5 gpm for a sustained period
from the water heater will cause the supply temperature at the
fixture to drop.
Large Usage:
In a typical residential application, a second water
heater is not necessary for capacity reasons. In large usage
applications (spa tubs and multi-head showers), a second
water heater is necessary to meet the hot water needs of the
customer. A gas or electric water heater can be added to the
system to cover these needs. A review of the required gpm and
gallons of hot water will be required to size the tank. Keep in
mind that multiple shower heads could legally use as much as 10
gpm.
Redundancy:
A second water heater will provide some
redundancy to the system if there is a pump failure in the heat
pump or some other issue not allowing the heat pump to run.
In addition, during defrost, the unit will not be generating hot
water.
Enertech Recommendation:
Based upon the considerations
above, Enertech recommends a second water heater for all
EAV installations. It is a relatively inexpensive addition that
provides many advantages.
Indirect Tank Sizing
Tank selection is based upon the number of bathrooms (types
of showers and tubs), dishwashers, washing machines, and
number of people in the home. Enertech offers two selections,
a 45 gallon indirect tank and a 65 gallon indirect tank. Typically,
a 45 gallon tank will handle two bathrooms with water efficient
fixtures, one dishwasher, and one automatic clothes washer. A
65 gallon tank will handle 3-1/2 bathrooms with water efficient
fixtures, one dishwasher, and one automatic clothes washer. If
the home has been identified as a large usage application (see
“Large Usage”, above), a second water heater in series with the
Turbomax indirect water heater is required. Even applications
that are not “Large Usage” will benefit from a backup water
heater for times when the outdoor temperature is very cold,
during defrost cycle, or for emergency use.
Backup Heat Considerations, EME (Electric Heat)
The EME model Indoor Module has an internal 9kW immersion
heater that can be used for supplementing the heat pump
capacity for hydronic heating and/or DHW heating. Depending
upon the application, either the internal heater or external
backup may make more sense. If additional heating capacity is
needed, a determination should be made based upon type of
heating required. For example, in most cases, a backup electric
heater is installed in the fan coil. Since the fan coil is required
for cooling anyway, it can be used for backup or for emergency
heat. For DHW, a second water heater can provide both backup
heating capacity and emergency DHW heating. The advantage
of the internal electric heat is that duct heaters and second
water heaters are not needed. However, if a pump fails, the
internal electric heat cannot operate. Each application must be
evaluated individually to ensure that the type of backup fits the
requirements. Installation diagrams in this IOM show the typical
connections used for additional heating back up sources or dual
fuel applications. Enertech recommends a second water heater
and electric heat in the fan coil, utilizing the internal electric heat
as optional.
Backup Heat Considerations, EMD (Dual Fuel Backup)
The EMD model Indoor Module has connections for an external
boiler that can be used for supplementing the heat pump
capacity for hydronic heating and/or DHW heating. For DHW,
a second water heater or a combi boiler can provide both
backup heating capacity and emergency DHW heating. Enertech
recommends a second water heater (or combi boiler) and
electric heat in the fan coil.
Section 3 - Installation Considerations
