Unico M Series User manual

Bulletin 30-30 / October 2007
© Copyright 2007 Unico, Inc.
General
The information on the following pages is to help the in-
staller save time, provide the best possible installation and
insure continuous trouble-free operation.
The Unico System Hot Water Coil is designed for use
with the Unico ‘M’ series air handlers and the Unico air
distribution system. The coil is designed to be used with
virtually any source of hot water including gas, oil, or
electric boilers; wood-fired boilers; solar heating systems;
or domestic hot water “Combo” systems.
Scope
These instructions apply to the Unico “M” Series slide-in
heating coils. Refer to Bulletin 20-20.4 for performance
tables for the HW2430 and HW3660. Refer to Bulletin
30-10 for the HW1218 performance tables and pressure
drops.
Refer to the boiler or hot water heater manufacturer’s
instructions for piping and pump layout and installation.
Equipment
Unico manufactures three size hot water heating coils that
are designed to slide into a Unico M Series Heating Mod-
ule or the single piece M1218 fan-coil unit. Model
HW1218 fits the M1218 unit, model HW2430 fits into the
MH2430 and MV2430 cabinets and model HW3660 fits
into the MH3660 and MV3660 cabinets. All necessary
mounting brackets are included. The Heating Modules are
sold separately or including the coil with the MH mod-
ules.
NOTICE TO INSTALLER AND EQUIPMENT
OWNER: RETAIN THIS MANUAL AT THE JOB.
FULL BUILDING INSULATION IS ESSENTIAL
FOR THE MOST ECONOMICAL OPERATION
General Precautions and Safety Tips
Do not attempt to install or startup unit without first read-
ing and understanding the appropriate sections in this
manual.
Installation should be in accordance with all local codes
and regulations and with the applicable National Fire Pro-
tection Association (NFPA) standards. In case of conflict,
local codes take precedence.
All electrical wiring should be in accordance with the
latest edition of the National Electrical Code and all local
codes and regulations. The unit is safety certified to UL
1995 and listed with ETL.
Always install a secondary drain pan when water could
cause damage.
Unpacking
All coils are inspected prior to shipping and are carefully
packaged in individual cartons. Inspect all cartons prior to
unpacking. Notify carrier of any damage.
Open each carton to remove the coils. Inspect for visible
signs of concealed damage and notify carrier of any such
damage. All materials are sold FOB Factory and it is the
responsibility of the consignee to file any claims with the
delivering carrier for materials received in damaged con-
dition.
Installation
The coil may be inserted into the Heat Module cabinet
before or after the module is installed. Refer to Bulletin
30-20 for the air handler installation instructions.
Use the following steps to insert the coil:
1. Remove the access plate from the side of the Heat
Module.
2. Cut the insulation away, using the opening as tem-
plate. Retain insulation for Step 5.
3. Slide the coil in as far as possible so return bends
press into the insulation on the inside of the module
CERTIFIED TO UL STD 1995
CAN/CSA STD C22.2 NO. 236
INSTALLATION MANUAL
FOR
‘M’ SERIES
SLIDE-IN HEATING COIL

Bulletin 30-30 —Page 2
© Copyright 2007 Unico, Inc.
cabinet. Coil must be fully inserted to assure that the
cover plate can be installed after coil is piped.
4. Pipe coil following instructions in “Piping” section
that follows below. Be sure system is filled with wa-
ter, bled of air and checked for leaks.
5. The insulation from Step 2 is to be used to insulate
the copper tubes of the coil. Notch the insulation for
the Water IN and Water OUT lines and position it in
the original opening over the coil tubing.
6. Install the coil cover plate supplied with the coil over
the insulation. Maneuver the plate so notches fit
around the water lines. Screw the cover plate in place
using screws removed from the access plate.
7. Caulk around the Water IN and OUT lines to assure
no air leakage. Also check around the edges of the
cover plate for air leaks with blower operating.
Caulk edges or seal with UL181A-P aluminum foil
tape.
Figure 1. Hot Water Coil with Cover Plate
For horizontal applications the heating module will be
installed upstream of the cooling module. For this config-
uration the hook-flange provided (loose) with the MH unit
must be attached to the cooling module (see Figure 2). In
hydronic heating only applications, use the hook-flange
on the blower module to attach the MH unit.
Cooling Module
or
Blower Module
(Hydronic heat only)
Heating
Module
Hook Flange
(shipped loose with MH unit)
Latch Hook
IL00389.CVX
Figure 2. Hook-flange Location
Piping
All piping must be in accordance with all local codes and
ordinances. Pipe sizing and pump selection must be de-
signed to match, allowing for the pressure loss in the coil
and all other fittings. Refer to ASHRAE Fundamentals
Handbook for design guidelines.
The Unico System Hot Water Coil can be piped as a sin-
gle zone or in a multi-zone system. In either system, the
water flow may either be continuous or intermittent.
In a continuous flow system, the fan is simply cycled on
and off by the thermostat. In an intermittent flow system,
water is circulated through the coil only when heat is re-
quired. The fan can run continuous or at the same time as
the water. The intermittent system will use either pump
on/off control, or mixing or isolation valves to control the
water flow.
An optional aquastat can be installed with the intermittent
system to prevent blowing of cold air by delaying the fan
until the water in the coil is hot.
M2430, and M3660 connections are 7/8-inch (22 mm)
sweat connections. M1218 connections are 5/8 inch (15.8
mm). Solder or braze the water connections, and then fill
the system. Bleed the air from the coil by backing off the
screw inside the bleed valve for venting. Water pressure
drops through the coil can be found in Bulletin 20-20.4
for the M2430 and M3660 and 20-18 for the M1218.
A secondary drain pan must be used under unit if installed
where a water leak could cause damage. Unico has avail-
able secondary drain pans for horizontal applications. For
vertical unit applications it will be necessary to fabricate a
drain pan which should provide at least ½-inch (12.7mm)
clearance around all sides at the bottom.
For vertical upflow arrangements where the air enters the
bottom of the unit, use the vertical plenum (MV) module
for the M2430 and M3660. Coil installation is identical to
the MH installation instructions and shown in Figure 1.
Detailed specifications for the MV unit are available in
Bulletin 20-20.5.
For vertical downflow (counterflow) installations it is
difficult to provide a secondary drain pan because of the
blower discharge at the bottom. If a secondary drain pan
is needed it must be fabricated with an opening for the
blower discharge and still provide a sealed drain pan.
Freeze Protection
If unit is in an unconditioned space below freezing, care
must be taken not to freeze the water in the coil. There are
two methods of freeze protection. The easiest is continu-
ously or intermittently circulate the water. Another meth-
od is to use a glycol-water antifreeze solution with a
81037

Bulletin 30-30 —Page 3
© Copyright 2007 Unico, Inc.
freezing point below the coldest temperature expected.
Using antifreeze, though, can reduce the output of the
coil.
If the coil is not in use during the cold temperatures, drain
the system then flush with a glycol solution.
Wiring
WARNING!
DISCONNECT ELECTRICAL SUPPLY BE-
FORE WIRING UNIT TO PREVENT INJURY
OR DEATH FROM ELECTRICAL SHOCK.
All electrical wiring must comply with all local codes and
ordinances.
For most heat-cool thermostats, it is necessary to install a
separate (not included) double-pole double-throw (DPDT)
relay as shown in Figure 3. This provides a set of open
contacts that serve as a switch to energize a boiler, a sole-
noid valve, or a pump. At the same time, the relay will
energize the indoor blower. This control diagram will still
allow for constant air circulation; however, the water flow
would need to be stopped to prevent overheating the con-
ditioned space. Using the DPDT relay allows you to start
the pump or open a valve when the thermostat calls for
heat.
In certain situations an aquastat is not used. For this setup,
connect the bypass wire as shown in Figure 3. This con-
figuration will energize the fan at the same time as the
boiler.
TT
AQUASTAT
Honeywell R8222D1014 or Steveco 90-340
Relay plusEnclosure(or equal)
DPDT RELAY
G
X
R
Y
W
Y
C
2
3
4
5
6
7
1
T
T
BOILEROR
PUMP
Honeywell T87F Thermostat with Q539A
subbase(or equal)
POWER
COMMON
COMMON
HEAT
COMPRESSOR
POWER
FAN
UNICOSYSTEM
AIRHANDLER
OUTDOOR
CONDENSINGUNIT
CONTROL WIRING DIAGRAM FOR UNICO SYSTEM
WITH COOLING AND HYDRONIC HEAT
WITH ISOLATED BOILER/PUMP SWITCH
14
3
26 5
THERMOSTAT
Bypass Wire
Option
Figure 3. Wiring Diagram for Cooling and Boiler Heating
Applications with DPDT Relay
If constant circulation is not needed, the blower can be
energized without the DPDT relay provided the thermo-
stat will energize the blower (‘G’ circuit) in heat mode.
Most electric furnace subbase thermostats will provide
this feature. A wiring diagram of this setup is shown in
Figure 4.
Note: A normal heating-cooling thermostat may not close
the “G” circuit on heating.
Honeywell R8228A1014
or Steveco 90-290 Relay plus Enclosure
(or equal)
SPNO RELAY
G
X
R
Y
W
Y
C
2
3
4
5
6
7
1
T
T
BOILEROR
PUMP
Honeywell T87F Thermostat with
Q539J subbase (or equal)
POWER
COMMON
COMMON
HEAT
COMPRESSOR
POWER
FAN
UNICOSYSTEM
AIRHANDLER
OUTDOOR
CONDENSINGUNIT
CONTROL WIRING DIAGRAM FOR UNICO SYSTEM
WITH COOLING AND HYDRONIC HEAT
WITH ISOLATED BOILER/PUMP SWITCH
IL00310c.CVS
THERMOSTAT (with optional fan during heat - electric heat option)
Note: Aquastat cannot be used in this
configuration. Consult Unico Customer
Service for additional information.
1
34
2
Figure 4. Wiring Diagram for Cooling and Boiler Heating
Applications with SPNO Relay
The Unico Advanced Control Board is another option for
hot water heating systems. The advanced control board is
adaptable to just about every practical heating application;
refer to Bulletin 30-38.
Startup
Sequence of Operation. The sequence of operation
greatly depends on the options installed and type of con-
trol thermostat used. Most thermostats have a fan AUTO-
ON switch. When the fan switch is set to ON, the “G”
circuit is closed and the blower relay is energized. The
indoor blower on the M1218 starts after about a 20-
second delay while the “M” series blowers will start when
the blower relay is energized.
The following paragraphs describe the sequence of opera-
tion when the fan is set to AUTO. If the fan switch is set
to ON, the sequence is the same except the “G” circuit is
always closed and the indoor fan is always operating.
Refer to Bulletins 30-10 and 30-20 for wiring diagrams of
the M1218 and “M” series modular air handlers.
Heating Cycle. When the thermostat calls for heating,
only the “W” circuit is closed for most thermostats, send-
ing a 24 V signal to a DPDT relay (separate from the air
handler control box). This external relay will close an
isolated switch that starts the boiler or pump. Then after
the optional aquastat is satisfied the indoor blower will
start. Suggested placement for the aquastat is on the water
inlet pipe as close to the coil as practical.
When the thermostat is satisfied, the 24 V signals are cut
and the pump and blower will stop. The indoor blower for
the M1218 continues to operate for about 30 seconds,
then stops. The system is now off.

Bulletin 30-30 —Page 4
© Copyright 2007 Unico, Inc.
Piping and Thermosiphoning Effect
Thermosiphoning is the natural, convective movement of air or water due to difference in temperature. In a hot water sys-
tem, if the water heater is installed lower than the coil, the hot water will not stay in the water heater when the pump is
turned off. The following piping schematic shows how thermosiphoning can be prevented:
OPTION 1: Install a check valve at the supply of the coil, downstream of the pump.
OPTION 2: Install a solenoid valve at the supply of the coil, downstream of the pump.
OPTION 3: Install a zone valve at the supply of the coil, downstream of the pump.
OPTION 4: Add a heat trap at the supply of the coil, downstream of the pump.
If the coil is installed lower than the water heater, there is no need for the options mentioned above.

Bulletin 30-30 —Page 5
© Copyright 2007 Unico, Inc.

Bulletin 30-30 —Page 6
© Copyright 2007 Unico, Inc.