First Aquatherm Series Installation And Application Manual
®
®
Aquatherm
INSTALLATION AND APPLICATION MANUAL
FOR
AQUATHERM
COMBO HEATERS
®
FIRST CO. - P.O. BOX 270969 - DALLAS, TEXAS 75227 - Ph. (214) 388-5751 - Fax (214) 388-2255 - www.firstco.com
1
Page
Introduction 3
Table of Contents
Sequence of Operation
General Description:
Air handler cabinet 3
Heating and cooling coils 3
Add-on hot water coil 3
Circulating pump 3
Flow control module 3
Check valve 3
Air purge valve 4
Blower door safety switch 4
Water heater 4
Boiler 4
Accessories:
Thermostat 4
Freeze protector 4
Equipment Sizing:
Condensing unit 4
Air handler 4
Water heater 5
3
Installation:
Duct work 5
Electrical 5
Water piping 6
1. Material 6
2. Solder connections 6
3. Insulation 6
4. Length 6
5. Shut-off valves 6
6. Piping connections 6,8-10
Air handler 6
Flow control module 6
Water heater 6
Multiple water heaters 7
Anti-scald valve 7
Start-up Procedure (heating cycle)
Troubleshooting 12
7
2
The Aquatherm® is a First Co. air handler that
converts a properly sized gas or oil-fired water heater
into a highly efficient, dual - purpose appliance that
can heat your home as well as provide hot water for
domestic purposes.
Any properly sized water heater (for heating) and
split system type condensing unit (for cooling) will
work with First Co. Aquatherm® air handlers and
are to be supplied by others. NO SPECIAL WATER
HEATER IS REQUIRED!
Aquatherm® air handlers are even compatible
with boiler systems.
Aquatherm® air handlers include a fan motor for
air circulation, hot water circulating pump, hot water
heating coil, air purge valve, check valve, components for low voltage control and most include a
cooling coil for air conditioning. All components in the
water piping meet NSF61 and/or california AB1953
requirements.
SEQUENCE OF OPERATION
(Heating mode)
When space heating is needed, the wall thermostat
energizes a small pump which circulates hot water
(135 to 140 degrees ) from the water heater to the hot
water coil in the air handler. As the fan motor forces
the cool return air from the home over the hot water
coil, the air absorbs heat from the hot water and this
warm air (about 105 to 110 degrees) is then circulated
throughout the duct system and into the home.
IMPORTANT. . . . . in most applications the water will
lose only 15 to 25 degrees in temperature while circulating through the hot water coil and will RETURN
to the water heater at about 115 to 125 degrees to
be reheated.
Add - on hot water coil: First Co. HWC series add-on
hot water coils are designed to be installed in either
existing or new duct work and operate in conjunction
with the existing fan motor to provide complete or
supplemental space heating from a gas or oil - fired
water heater. These coils are completely cased and
utilize the separate “flow control module” which can
be installed at the water heater for easy access and
service (see “flow control module”).
Circulating pump: All circulating pumps circulate
water at a rate of 3 to 6 gallons per minute and are
either factory installed or included as part of the field
installed “flow control module”. These pumps are
designed to circulate a precise amount of hot water
between the water heater and air handler or add - on
coil.
Flow control module: This U.L. Listed device con
sists of the circulating pump, check valve, air purge
valve, 6' plug - in line cord and pump relay. The
module is sold & shipped separately with HWC add
- on hot water coils. The module can be field installed
anywhere in the hot water heating loop between the
water heater and hot water coil and offers the advantage of being able to install the pump assembly in
the most appropriate location for service and maintenance. Modules must be installed with the motor
in a horizontal position. Junction box should not be
located underneath the pump.
FLOW CONTROL MODULE - WIRING DIAGRAM
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GENERAL DESCRIPTION
Air handler cabinet: Air handlers with cabinets are
made of galvanized steel and fully insulated to reduce
noise and maximize efficiency. Throwaway filters are
factory installed in most air handlers.
Heating and cooling coils: All heating and cooling
coils are made of copper tubes with mechanically
bonded aluminum fins for maximum heat transfer.
Manual air vents are included on all hot water coils.
Cooling coils have either piston - type metering de
vices or field installed expansion valves. Primary
and secondary condensate drain connections are
provided on each cooling coil. All primary connections
are 3/4 inch MPT.
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Check valve: A check valve is factory installed in
the hot water loop to eliminate any thermosyphoning
(hot water circulating through the heating coil) while
operating in the cooling mode. The check valve is
installed within the air handler or as part of the “flow
3
control module”.
Air purge valve: All air handlers and / or “flow control
modules” include a large manual air purge valve to
facilitate air removal from the heating loop prior to
system start - up. When the air handler and water
heater are piped according to First Co. instructions,
the air in the hot water coil and piping will only need
to be removed before initial start - up or after air has
gotten into the system because of a plumbing leak
or break in a water main. This can be accomplished
by using the 2 - step process described under “start
-up procedure”.
Blower delay relay: FWA-HW,HBXB-HW,HBQB,UCHW and UCQB series air handlers include a blower
delay relay that allows the circulating pump to operate
on a call for heat for 20 to 45 seconds
motor comes on to deliver warm air quicker when the
heating system starts. This relay also keeps the fan
motor on for 20 to 45 seconds after the thermostat
is satisfied in the heating cycle to maximize the efficiency of the heating coil.
before the fan
All other air handlers require a 24 volt thermostat
that energizes the fan motor on a requirement for cool
ing and heating. This is commonly called an "electric
heat" thermostat. CAUTION . . . . . a gas furnace
thermostat will NOT work with these units because
the fan motor will not come on when the thermostat
calls for heat.
Normal heat anticipator setting should be 0.3 to 0.4.
If a set-back thermostat is used, allow extra time for
recovery in the morning.
Freeze protector: Kit number 941-1 can be field
installed on any Aquatherm® air handler or add -on
coil and is highly recommended when the air handler
or hot water coil is installed in a space that may be
subjected to freezing temperatures such as in an attic
or crawl space. The sensor attaches to the hot water
coil and is wired to R and W in the low voltage circuit.
If for any reason the temperature of the hot water coil
falls below 38 degrees the sensor will bring on the
pump to circulate hot water. This will occur even if
the thermostat is in the "off" position.
-
Flue gas safety switch: All "Q" type air handlers,
as well as FWA-xx series air handlers, include a
factory installed flue gas safety switch (except 5 ton
models). When the blower door is removed for any
reason the air handler fan motor will not operate.
This is especially important when the water heater
is in the same closet as the air handler because
products of combustion from the water heater flue
pipe could be circulated throughout the duct system
if the air handler were allowed to operate without the
door in place.
Water Heater: Any properly sized gas or oil - fired
water heater will work ( even direct vent or powered
vent types ). Electric water heaters are not recom
mended because of their slow recovery rate. Water
heater warranties are not affected by this system
since no modification of the water heater is necessary.
Selection of higher efficiency water heaters will result
in even greater savings.
Boiler: Most First Co.
and add - on hot water coils are also compatible with
boilers and instantaneous water heaters. Please contact the factory for assistance in selecting the proper
equipment for these applications. (See Page 10 for
wiring diagram of multiple air handlers.)
Aquatherm® air handlers
EQUIPMENT SIZING
Condensing unit: The condensing unit should be
sized to meet the calculated heat gain according to
an approved heat gain formula.
Air handler: Select an air handler with a heating
BTUH that exceeds the structure's calculated heat
loss and a cooling coil matched to the tonnage size
of the outdoor condensing unit.
Special note . . . . . the actual heating output of the
air handler (BTUH) will not be greater than the heating
output of the water heater (water heater BTUH input
multiplied by it's recovery efficiency) regardless of the
listed heating BTUH of the air handler.
-
ACCESSORIES
Thermostat: All "Q" type air handlers will operate
with any standard 24 volt heat / cool or heat pump
thermostat.
Water heater: Add 10 to 20% to the structure's heat
loss to obtain the minimum output of the required
water heater (output = input x recovery efficiency).
A minimum 40 gallon high recovery and / or high efficiency gas or oil-fired water heater is recommended.
In addition to the above formula, the following vol-
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