Group Title: Historic St. Augustine: De Mesa Sanchez House, Block 7 Lot 6
Title: [Letter to Bob Steinbeck re De Mesa - Sanchez house]
Full Citation
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 Material Information
Title: Letter to Bob Steinbeck re De Mesa - Sanchez house
Series Title: Historic St. Augustine: De Mesa Sanchez House, Block 7 Lot 6
Physical Description: Correspondence
Language: English
Creator: Hammond, James M.
Publication Date: 1983
Subject: Saint Augustine (Fla.)
43 Saint George Street (Saint Augustine, Fla.)
de Mesa-Sanchez House (Saint Augustine, Fla.)
Spatial Coverage: North America -- United States of America -- Florida -- Saint Johns -- Saint Augustine -- 43 Saint George Street
Coordinates: 29.896429 x -81.313225
 Record Information
Bibliographic ID: UF00091263
Volume ID: VID00195
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution.
Resource Identifier: B7-L6

Full Text

THOMAS N. EVANS, JR.. P.. 904/388-071
29 November 1983

Historic St. Augustine Preservation Board
P. O. Box 1987
St. Augustine, Florida 32084

ATTN: Bob Steinbeck

SUB3: De Mesa-Sanchez House

Dear Bob:

This letter will summarize our conversation of Tuesday, 22 November 1983 on the air
conditioning units on the referenced project.

Over the past several weeks I was finally able to discuss this problem with both Carroll
Air Systems, representatives of the unit manufacturer, and Fred Keene, installing
contractor. I requested Carroll Air send me the installation and service manual since
you indicated that you never received one. In going through this manual I am sorry to
see that the preventative maintenance method of back flushing the condenser is not
mentioned. This method, that I discussed with you, however is highly recommended by
Carroll Air and I agree with them.

I am enclosing two copies of the manual for your use as well as a sketch that you should
give to the service mechanic that is going to work on your units so we will end up with
proper valving to permit reverse flushing and cleaning of your condenser.

As we discussed, the condensers should be in good shape provided they are thoroughly
flushed with the proper cleaning solution for the fouling material that is present. I am
not going to tell your mechanic what to use because if he is good he will know. He
should also check the flow of water the unit is receiving. A lack of adequate flow can
be detrimental to the unit.

The preventative maintenance we discussed would require a check after six months of
operation to see how much build-up occurs in the condenser in that period of time. At
that point the mechanic could tell you whether a flushing is required every six months
or every year. Although you apparently have bad quality water I feel every year should
be adequate, but have it evaluated in six months.

As I mentioned, your compressors are under warranty and will be replaced by the
manufacturer without cost to you. All labor cost, however, will be at your expense.
Make sure you get new 5-year warranties on your new compressors.

NOV 30 1983

Mr. Bob Steinbeck

I have checked the shop drawings to see what safety controls are available and which
ones you have. On these units no complete lockout controls with the exception of the
short cycling type is available. Your units have this control. This should lock out your
unit if it tries to keep restarting. Have the service mechanic check to see if this
control is functioning. It is designed to keep your compressor from killing itself trying
to keep starting when it shouldn't.

If we can provide additional information, please call us.

Very truly yours,


3 mes M. Hammond, P.E.


Enclosures as stated.

cc: Mr. Herschel Shepard, FAIA w/o enclosure

Page 2

29 November 1983


The Command-Aire Heat Pump is a self-contained, factory assembled
unit. Each unit has been inspected and operationally run tested
at the factory by Quality Control. The unit has been packaged to
arrive in good condition, however mishandling in transit can cause

Report evidence of visible and concealed damage to the carrier's
agent immediately. Request an inspection and a report to originate
a claim.


The basic principle of operation of the water to air heat pump
is that heat is extracted from the air and rejected to the water
on the cooling cycle. Dehumidification is also achieved on the
cooling cycle by removal of moisture from the air in the form of
condensate. In the heating cycle the refriaerant flow is reversed
and heat is extracted from the water and used to warm the room air.

Basic components used in the system are the compressor, tube in
shell heat exchanger, a finned coil heat exchanger, a reversing
valve, and a circulating blower. The reversing valve operates the
system in either the cooling or heating mode. (See Fig. 1 & 2)

A manual selector switch or an automatic changeover switch on the
thermostat determines whether the unit will operate on coolina or
heating cycle. The unit will be controlled automatically by the

The Command-Aire Heat Pump is a factory assembled unit, requiring
electrical power of the proper voltage, an adequate supply of water
in the range of 600 to 950F. A drain for wasting the condensate
water is required. Duct work to supply air to be conditioned and
return conditioned air is also required.


Typical installation of the SWP "vertical" models is illustrated in
the following diagram: Fig. 3 Unit in a Closet Installation.

Typical installation of the SWPH "horizontal" models is illustrated
in the following diagram: Fig. 4 Ceilina mounted installation.

For acceptable operation of the heat pump; particular care in
location, setting, and connection of the heat pump must be exercised.
The following points should be considered when installing a Command
Aire Heat Pump.

A) All units should be installed to provide space for removal
of access panels for servicing the compressor and air
handler sections.
* B) Prevention of noise and vibration transmission to the occupied
spaces, building structure, ducts and pipina. It is recommended
that vibration eliminator pads be installed under the base
of vertical units. The compressor is internally spruna and

bolted to the base with special isolation mounts. After
installation of the unit, the hold down nuts should be
loosened so that the compressor is floating free. Install
flexible duct connections between the unit and the duct
C) The ducts should be designed for velocities in accordance
with ASHRAE standards. It is recommended that airborne
noise be controlled with sound attenuating materials. The
resistance of the duct work and discharge and return grilles
must be within the limits of the external static pressures
shown on the specification sheet for the particular unit being


Recommended water piping to the unit is shown in Figs. 5 & 6.
Connect water and condensate by means of flexible hose connections.

Hoses used to make water connection to the unit must be suitable
for the system water pressure.

The condensate line in SWP/H should be trapped, as required by local
codes, at the unit and should be pitched away from the unit.

Balancing valves installed in the supply and return water line
to the unit will allow for adjustment of proper flow to each
unit and provide a means of water shut-off should it be necessary
when servicing the unit. Indicating flow meters in the supply
line to each unit are very desirable.

Successful operation of the heat pump depends on the correct 0
quantity of water to the unit. Undersized pipes and low pressure
will result in low water flow causing high head pressure in
summer operation and possible freezing of the water in the heat
exchanger during the winter operation. Excessive water flows will
overload the unit in the heating cycle and reduce capacity in the
cooling cycle.

Water flow rates for efficient operation are listed in the product
specification sheets. The water temperatures to the unit must
be between 60OF minimum and 100oF maximum. The unit will not
operate efficiently at water temperatures outside of this range and
may result in damage to the unit.

The water must be clean, free of sand and solid foreign matter
and entrained air. Air in the system will reduce the capacity
of the heat exchanger, cause oxidation and scale, and create
noise in the piping.

Galvanized pipe or fittings are not recommended for use with
these units due to possible electrolysis action.

When using a semi-closed system, with an "open" cooling tower the
water treatment system should be operational with initial water
flow and must condition the water to prevent corrosion and/or scale
for trouble free operation.

NOTE: Operation of C/A units on poor quality water or
incorrect flow is detrimental to the C/A units
and voids the warranty.


Power wiring to the heat pump should be in conformance with
applicable codes and connected as shown on the wiring diagram
furnished with the unit. No starters are required.

Each Heat Pump is furnished for a rated voltage frequency and
phase marked on the data plate. For units with a nameplate
marking of 208/230 volts, the permissible operating voltage
range is 197-253 volts. For units with other voltage markings
the operating range must be within plus or minus 10%.

The nameplate data indicates the fuse size or circuit size for
each compressor circuit. Make certain that the unit is adequately

For 208 volt operation make the necessary change in transformer
wiring as shown on the wiring diagram furnished with the unit.

Low voltage wiring between the terminal board in the unit control
panel and the wall thermostat should be made in conformance with
applicable codes. Color coded low voltage cable is recommended to
simplify wiring between the thermostat and unit.


Idle units may have numerous problems on startup mainly for the
reason of not being used. Freon migrates to the condenser taking
entrained oil with it thereby rendering the compressor relatively
dry of lubrication; check valves will malfunction for lack of
oil, etc. These things could relate to problems such as lack of
heating or cooling and may cause failures of out of warranty parts
upon start-up,

Units that are installed in unoccupied spaces should be in a
minimal operation mode. The following is recommended:

A) During Summer (Cooling Season) Thermostat set at
850F, system switch on COOL, fan switch on AUTO.

B) During winter (Heating Season) Thermostat set at
600F, system switch on HEAT, fan switch on AUTO.

This should allow each unit to operate enough to maintain a
lubricated system and not expend any great amount of electrical


After the unit has been installed, wired, piped and ducted, the
unit is ready to be checked, tested and balanced for continuous

Before starting the unit check the following:

1) Proper voltage to unit
2) Correct fuse sizes
3) Tight electrical connections
4) Water system clean and flushed
5) Air purged from water system

6) Set water flow for the proper quantity
7) Water temperatures between 600F and 1OOoF
8) Condensate line clear and unclogged
9) Blower wheel free to rotate
10) Return air filter is installed
11) Access panels and enclosures in place
12) Thermostat on OFF position

To start and balance the unit follow these steps:

Adjust the room thermostat to its lowest setting and turn the
thermostat switch to COOL position. Set the fan switch on AUTO.
The unit should operate. If the unit has failed to start see
the trouble shooting guide section.

The difference between the entering and leaving water temperatures
can be felt. Determine that the leaving water temperature is
between 850and 1050F (depending on the incoming water temperatures
and unit design conditions as specified in the Engineering Data
Sheets.) Normally about 100 120 hotter than supply water.

Check for cool air at the outlets after a few minutes of operation.
Air flow in each area should be adjusted to the design airflow.
The air temperature should drop approximately 150 to 250F de-
pending on the airflow thru the unit and the wet bulb temperature.
If the air is too cold (more than 220F drop from entering air)
or too warm (less than 160 drop from entering air) check the
air flow.

Turn the thermostat selector switch to OFF position, a "hissina"
sound should be noticeable at the unit indicating a properly
functioning reversing valve.

Let the system pressure equalize for about two minutes. Adjust
the thermostat to its highest setting and the thermostat selector
switch to HEAT.

The difference between the entering and leaving water temperatures
can be felt. Determine that the leaving water temperature is
between 50F and 750F (depending on the incoming water temperatures
and unit design conditions as specified in the Engineering Data
Sheets.) Normally about 70 100 cooler than the supply water.

Check for hot air at the outlets after a few minutes of operation.
Air flow in each area should be adjusted to the design airflow. The
air temperature should rise approximately 200F to 400F depending
on the airflow thru the unit and the wet bulb temperature. If
the air is too hot (more than a 400F rise from entering air) or
too cool (less than a 20F rise from entering air) check the
air flow.

Check for any vibrations, unusual noises or water leaks.

After being satisfied that the unit operates normally and the
system is ready to run, the thermostat selector switch should
be set on either HEAT or COOL depending on the climatic conditions
and temperature setting at the desired level of comfort.


Operation of your Command-Aire Heat Pump is designed for ambient
air temperatures of not less than 400F.

The standard model is designed for indoor installation and when
installed in an unconditioned space, the unit may not start in
cool weather, (approximately 500F). In this case, it may be
necessary to start the unit on cooling in cool weather for three
to five minutes, then shut off and turn to heat after one minute
shut down. Also, check the freeze protection thermostat because
it may be affected by ambient temperature.
The Command-Aire unit is equipped with safety controls which include
a high pressure control, freeze protection thermostat, and a motor
overload switch in larger models, set to shut off the compressor
under abnormal operating temperatures and pressure conditions. Other
optional safety controls are available such as low pressure switch.
If any of these controls shut off the compressor, a lockout relay
prevents short cycling from the abnormal condition. When conditions
have been corrected the control lockout can be reset by setting the
thermostat selector switch to OFF, waiting a few minutes for the
system pressures to equalize, and then returning to HEAT or COOL.
If the condition continues an authorized serviceman should check
out the unit.

For economical operation of the Command-Aire Heat Pump it is advisable
to prevent heat transmission from the outdoor or other non air
conditioned spaces, to the conditioned space.

A popular but erroneous concept is that if the thermostat is set
at extremely low or high temperatures the unit will cool or heat
faster. It is good practice to set the thermostat at the desired
level of comfort and leave it there without trying to achieve
comfort levels by constantly manually changing the thermostat.

Like any other type of mechanical equipment, the Command-Aire Unit
performs best when it is well maintained.

There is no substitute for the "know how" and experience of a
competent refrigeration and air conditioning serviceman.


Set the heat anticipator scale to match the primary control rating.
When using a thermostat with 2 stages of heating, set both heat
anticipators to match their respective primary control rating.

The current draw of each heating stage must be measured with the
thermostat removed for best results.
1) Connect an ac ammeter of appropriate range between the heat-
ing terminals of the subbase -
Stage 1 between R and W1
Stage 2 between R and W2
2) Move the system switch to HEAT or AUTO.
3) After 1 minute, read the ammeter and record the reading for
each stage.
4) After mounting the thermostat, set the adjustable heat
anticipator to match the respective reading measured in step
NOTE: Wiring to thermostat must be run in 18 quaqe or heavier wire
to keep the resistance of the thermostat circuit to less than 1 ohms.


Regular service greatly improves the operating efficiency, re-
liability and longevity of Command-Aire Units.

Maintenance on the unit is simplified to the following items.

1) The Command-Aire Heat Pump is furnished with a one inch
fiberglass throwaway type air filter. This unit should
not be operated without this filter in place.

Filters should be inspected every three months and replaced
when it is evident they are dirty. Unit operation becomes
very inefficient with dirty filters. Three or four filter
replacements may be necessary a year.

2) Condensate drains can pickup lint and dirt, especially with
dirty filters. Inspect the condensate pan and drain twice
a year to avoid the possibility of overflow.

3) For units that are on city water or well water, it is im-
portant to check the cleanliness of the condenser. Should
the condenser become contaminated with dirt and scalina, as
a result of bad water, the condensers will have to be back
flushed and cleaned with a chemical that will remove the
scale. This service should only be performed by an experienced

Cooling Towers must be maintained, kept free of alaae and con-
taminates and should have water treatment.

4) Check the contractors and relays within the control panel at
least once a year.

It is aood practice to check the tiahtness of the various
wiring connections within the control panel, (especially
when line power wiring to the machine is aluminum.)

5) The blower motors are rated permanently lubricated. The
belt driven blowers require oiling twice a year with a
few drops of #20 SAE non-detergent oil. This should be
done by a competent refrigeration service mechanic and
not over oiled. It is good practice to inspect for belt
wear and tension at this time. Correct belt tension is
for the motor to be resting by its weight on the belt.
If the belt is excessively tight there will be excessive
heat generated in the bearings and ultimate failure.

On a closed circuit water system there are auxiliary
equipment such as boilers, towers, and pumps which also
require preventive maintenance just as much as the units
for a trouble-free system.

COOLING CYCLE: Range of Approximate Operating Pressures (PSIG)*


ON 850 950 1050

75 66-70 190-210 68-74 220-240 70-76 240-260

80 68-72 195-215 70-76 220-240 72-78 245-265

85 70-74 200-220 74-78 220-240 76-80 250-270

* Variances from these operating pressures will occur from machine to
machine, model to model.

HEATING CYCLE: Range of Approximate Operating Pressures (PSIG)*


600 530 55-70 230-260
700 700 630 60-75 250-280

800 730 65-80 270-310

600 530 60-75 240-270
750 700 630 65-80 260-290

800 730 70-85 270-325
Variances from these operating pressures will occur from machine to
machine and model to model.





High Pressure
Control and
Freezestat Control

Check setting, calibration and

Check for loose or broken wires
at compressor, capacitor or

The unit could be off on the hiah
pressure or freezestat cut out
control. Reset the thermostat
selector switch to "OFF". After
a few minutes turn to "Cool". If
the compressor runs, unit was off
on safety control (see complaints
for possible causes.)
If the unit still fails to run,
check safety controls for mal-
function by jumpering the various
safety control to determine cause.

If the compressor dome is too hot
to touch the overload will not reset
Compressor until the compressor cools down.
Overload If the compressor is cool and the
Open overload does not reset, there
may be a defective or open overload.
If the overload is external replace
the overload, otherwise replace the

Try an auxiliary capacitor in
parallel with the run capacitor
Inoperative momentarily. If the compressor
Compressor starts but the problem reoccurs
on starting install an auxiliary
start kit. The hard start kit com-
prises of a recommended start re-
lay and correctly sized capacitor.
If the compressor still does not
start, replace the compressor.
Defective Check capacitor, if defective
Capacitor remove & replace.

Compressor Internal winding grounded to the
Motor compressor shell. Replace the
Grounded compressor.

Compressor Check continuity of the compressor
Windings windings with an ohmmeter. If the
Open windings are open, replace the

Supply Low

If the voltage is below minimum vol-
tage specified on the dataplate,
contact local power company.


Set thermostat selector switch on
"Cool" and lowest temperature
setting, unit should run. Set
Thermostat thermostat on "Heat" and highest
temperature setting, unit should
run. Set fan on "Run", fan should
Srun. If unit does not run all three
cases the thermostat could be wired
ENTIRE incorrectly, or faulty.
DOES Broken or loose
DOES Broken or loose Replace or tighten the wires.
NOT RUN wires
Blown Fuse Replace fuse or reset circuit

Check 24 volt transformer for
Control Center burnout or voltaae less than 18

Voltage Supply If voltage is below minimum vol-
Sow e S y tage specified on dataplate, con-
tact local power company.
High Pressure Check for defective or improperly
Switch calibrated high pressure switch.

* Lack of adequate water flow.
UNIT OFF Entering water too warm.
ON Scaled or pluaged condenser.
CUT-OUT Pressure On HEATING Cycle:
CONTROL Too High Lack of adequate air flow.
Check blower, clogged filter, coil
or restrictions in duct work.
Entering air too hot.
Entering water temperature to hiah.
Excessive water flow.

The unit is overcharged with re-
Refrigerant frigerant. Bleed off some charge
Charge or evacuate and recharge with
specified amount of R-22.

UNIT OFF Check for low water temperature,
ON Freezestat low water flow, and low ambient.
LOW TEMPERATURE Increase water flow for lower
CONTROL temperature.



Improperly located thermostat (e.g.
Thermostat near kitchen sensing inaccurately
the comfort level in living area.)

Check for defective compressor.
If discharge pressure is too low
Compressor and suction pressure too hiah,
compressor may not be pumping prop-
erly, if so replace compressor.
Reversing Reversing valve creating
Valve by-pass of refrigerant from dis-
charge to suction side of compressor.
Airflow Lack of adequate airflow or improper
INSUFFICIENT distribution of air.
OR Loss of Check for leaks in ductwork or
HEATING Conditioned Air introduction of ambient air through
by Leaks doors and windows.

Incorrect Water Check water flow rate & reset if
Flow necessary.

Operating Incorrect operating pressure.
Pressure (See chart)

Check strainer and capillary tubes
for possible restrictions to flow
Refrigerant of refrigerant. The refrigerant
System system may be contaminated with
moisture, non-condensibles and
particles. Dehydrate, evacuate
and recharge the system.

Recalculate heat gains or losses
Unit for space to be conditioned. If
Oversized excessive rectify by adding in-
sulation, shading, etc.

Check thermostat heater setting.
Thermostat The thermostat differential may be
UNIT set too narrow.
SHORT Wiring and Loose connections in the wiring or
CYCLES Controls the control contractors defective.

Defective compressor overload,
Compressor check and replace if necessary. If
Overload the compressor runs too hot it
may be due to an incorrect refrig-
eration charge.





Blower and
Blower Motor


The hold down bolts used for
shipping should be lessened so that
the compressor is floating free on
its isolator mounts. Make sure
the compressor is not in direct
contact with the base or sides of
the cabinet. Excessive noise will
occur if the compressor has a
broken valve or loose discharge
tube. Replace the compressor.

Blower wheel rubbing the blower
casing. Adjust for clearance and
alignment. Bent blower, check and
replace if damaged. Loose blower
wheel on shaft. Check and tighten.
Defective bearings. Check and replace.

A "chattering" noise in the contactor
could be due to control voltage
less than 18 volts. Check for low
supply voltage, low transformer
output or extra long runs of thermo-
stat wires. If the contacts or coil
is defective repair or replace.

Check for loose screws, panels or
Rattles and internal components. Tighten
Vibrations and secure. Copper piping could
be hitting the metal surfaces. Care-
fully readjust by bending slightly.

Undersized ductwork will cause high
Air Noises airflow velocities and noisy opera-

Water Noises

Sand or gravel in water.
Air in water will cause a noise
which sounds like travel or sand
in water.

Excessive water through the water-
cooled heat exchanger will cause
a noise. Throttle the water flow
to correct quantity.



.- I SWH-SWPH Installation Detail


(I) OPEN RETURN : Use isolation boot shown above made from
duct board or sheet metal duct with 3' of liner adjoining unit.
(2) DUCTED SUPPLY/RETURN : Use 900 turn shown below made
from duct board or sheet metal duct with 3' liner adjoining
(3) Use flexible duct connectors and turning vanes on sheet metal
duct work.
(4) Select proper duct size and install per Ashrae guide.

CA-os080- HERS

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