Enertech Global
40
EAV - EME/EMD Rev. A Models
Installation and Operations Manual
Note:
Flow Sensors installed in this equipment are extremely
sensitive to micro-bubbles.
•
Enertech recommends “Home Run” style piping (see
Figure
12e
) to help facilitate air removal, but also for ease of access
to the zone valves. In the “Branch” style piping in
Figure
12e
, branches 2 and 3 can be particularly difficult to purge,
depending upon the size of the supply/return lines feeding
the two branches, especially if fan coils are piped in this
manner.
•
Proper Flow Rate:
In
Figure 12b
, there could be two
different flow rates on each side of the hydraulic separator,
depending upon the size and number of zones and the size
of the heat pump. Supply/return lines for the heat pump
size of the hydraulic separator must be sized for the heat
pump flow rate; supply/return lines on the system pump
side of the hydraulic separator must be sized based upon
the number and size of connected zones.
•
Supply/Return Pipe Diameter:
Any hydronic system with
parallel piping to various zones requires large enough piping
diameter to provide sufficient flow to all zone, but also to
assist in purging air from the system. The flow rate though
the supply/return lines must be high enough to achieve 2
feet per second velocity in all of the parallel branches.
“Home Run” style piping, as mentioned above, is helpful in
purging air, as well.
•
Low Pressure Drop:
Selecting Pipe diameter from Table 2
for supply/return lines will help ensure low pressure drop
and good performance.
The example below provides steps for sizing the piping for a
typical residential system.
Example:
System includes a model 060 heat pump with one 3 ton fan coil
and 3 radiant zones. Two radiant zones each have 5 circuits and
one radiant zone has 3 circuits (13 total circuits). All circuits are
1/2” PEX piping.
The radiant heating calculations determined that the PEX loops
will be at 9” O.C. spacing and that the flow rate per circuit will be
0.42 GPM (5.5 GPM total). Since the fan coil is larger than 2 tons,
a buffer tank is not needed (the system will use a hydraulic
separator). The system will use 25% Fernox Alphi-11 propylene
glycol antifreeze. The following steps should be used to
determine pipe sizing:
1.
Determine flow rate and pipe diameter for piping from
hydraulic separator to the “Home Run” hydronic zones (see
items 2 & 3 in
Figure 12f
). From Table 1, the fan coil needs 9
GPM. Also from Table 1 the 1/2” radiant tubing could be up
to 0.75 GPM per circuit, but since 0.42 GPM was specified,
the application will use the specified flow rate (13 x 0.42 =
5.5 GPM). Total flow rate is 14.5 GPM (9 + 5.5). From Table
2, the supply/return lines from the hydraulic separator to
the zones should be 1-1/4” copper or 1-1/2” PEX.
2.
Similar calculations should be done for each zone. For the
fan coil zone (9 GPM), 1” copper or 1-1/4” PEX should be
run to the fan coil; for the 5 circuit manifold, 3/4” PEX may
be used (same for the 3 circuit manifold).
Table 2: Piping Design Flow Capacities
Table 1: Recommended Flow Rates
Section 6: Unit Piping Installation
Heat Pump
EAV040 – 12 GPM
EAV060 – 15 GPM
MPH Fan Coils/Air Handlers & ACH/MCH A-Coils
MPH/ACH/MCH024 – 6 GPM
MPH/ACH/MCH036 – 9 GPM
MPH/ACH/MCH048 – 13 GPM
MPH/ACH/MCH060 – 13 GPM
Multi-Aqua Fan Coils
High-wall units
Console Units
MHQWW-9 – 3 GPM
CFFWA-3 – 3 GPM
MHQWW-12 – 6 GPM
CFFWA-6 – 4.5 GPM
MHQWW-18 – 6 GPM
CFFWA-8 – 5.5 GPM
MHQWW-24 – 7 GPM
CFFWA-12 – 8 GPM
MHQWW-36 – 10 GPM
CFFWA-16 – 10.5 GPM
CFFWA-20 – 12.5 GPM
Radiant Floor
1/2" PEX – 0.5 to 0.75 GPM per circuit
5/8" PEX – 0.75 to 1 GPM per circuit
3/4" PEX - 1 to 1.25 GPM per circuit
Example: A 5 loop manifold with 1/2” PEX circuits would need
supply/return piping capable of supplying 2.5 to 3.75 GPM
DHW Piping
Use flow rate for heat pump
Pipe Diameter/Type
Maximum Flow Rate (GPM)
Floor Loop* Supply/Return**
1/2” PEX
0.75
N/A
5/8” PEX
1
3/4” PEX
1.25
4
3/4” Copper or 1” PEX
N/A
7
1” Copper pr 1-1/4” PEX
12
1-1/4” Copper or 1-1/2” PEX
17
1-1/2” Copper
25
2” Copper
45
* Based upon 300 ft. circuits.
**Based upon 25ft. length (one-way) and 4 elbows with water.
When using antifreeze, increase pipe size to the next size if
close to the maximum flow rate.
