pick heaters 6X7 User manual

PICK VARIABLE FLOW SERVICE MANUAL
1
INSTANTANEOUS STEAM INJECTION VARIABLE FLOW HEATER
SERVICE MANUAL

PICK VARIABLE FLOW SERVICE MANUAL
2
DO NOT DISPOSE OF THIS MANUAL
The information on the following pages will be useful after installation. Please direct this manual
to personnel responsible for the ongoing maintenance and operator of the Pick Heater.
IMPORTANT: DO NOT OPERATE THE PICK HEATER SYSTEM IN PARALLEL
WITH ANY OTHER HEATING SYSTEM, INCLUDING A SECOND PICK HEATER
SYSTEM.
CAUTION: NEVER USE HANDS OR OTHER PARTS OF THE BODY TO SEARCH
FOR WATER OR STEAM LEAKS IN THE SYSTEM. HIGH VELOCITY LIQUIDS OR
STEAM COULD PENETRATE THE SKIN AND CAUSE SERIOUS INJURY.
Any questions about the installation or operation of your Pick Heaters should be directed to your
local Pick Heater representative, or Pick Heaters at 800-233-9030. (Outside the US and Canada,
please call 262-338-1191 or Fax [phone].)

PICK VARIABLE FLOW SERVICE MANUAL
3
PICK INSTANTANEOUS STEAM INJECTION VARIABLE FLOW HEATER
INSTALLATION, START-UP AND OPERATION
Warranty……………………………...…………………………….……………………….……..3
Safety information……………...………………………………………………………….………4
Troubleshooting Tables………………………………………………………………………...5-10
Injection Tube Service …………………………………………..………………….……………11
Obtaining the Proper Cleaning Solution ………………………………………………...……….11
Cleaning…………………………………………………………………………………………..11
Heater Disassembly…………………………………………………………………...…….……13
Models 6X10 through 6X500…………………………………………..…………….….13
Model 6X7………………………………………………………………………….……13
Injection Tube Cleaning……………………………………………………………………….….14
Injection Tube Disassembly………………………………………………………………………14
Illustrations……………………………………………………………………….……..…….16-18
Reassembly/Installation of Injection Tube……………...……….………………………..……...19
Heater Reassembly……………………………………………………………………………….19
Pump Service………………………………………………………….……………………….…20
Relief Valve………………………………………………………………………………………20
Steam Control Valve……………………...………………………………………………………21
Steam Valve Opening Pressure Adjustment……………………………………………..21
Packing Gland Adjustment………………………………………………………………22
Temperature Controller Adjustment and Service………………………………………………...23
Other Troubleshooting Issues…………………………………………………………………….24
Replacement Parts...…………………………………………………………………………....…25
The Pick Heater Warranty
Every Pick heater is warranted to perform at its rated capacity when properly installed ad
maintained, and when operated under the conditions originally specified. Any change in operating
conditions, or unauthorized modifications to the equipment, will void this warranty.
Every Pick heater is warranted to be free from defective materials or workmanship for one year
following installation, or 18 months from the invoice date, whichever occurs first. Any defective
parts will be replaced FOB West Bend, WI. Please note that this warranty does not extend to
labor or installation costs involving replacement parts. Determination of repair or replacement
will be at the discretion of Pick Heaters, Inc. Pick Heaters shall not be liable for losses or delays
resulting from damaged or defective parts. This warranty does not cover damage caused by
improper installation or adjustment, or by willful neglect of specified operation and maintenance
procedures.
Equipment not manufactured by Pick Heaters, Inc. which is supplied as a component is not
covered by this warranty. However, Pick Heaters, Inc. will pass on to the purchaser any
adjustment made by the supplier of any defective equipment.
Please read these instructions completely before installing or operating your Pick Heater.

PICK VARIABLE FLOW SERVICE MANUAL
4
This symbol is placed in this manual to call attention to safety precautions for the installation and
operation of this product. Observe ALL instructions accompanied by this symbol. This symbol
means ATTENTION! BECOME ALERT! YOUR SAFETY IS INVOLVED!
Be familiar with the varying degrees of hazard represented by the signal words CAUTION and
WARNING.
CAUTION indicates a need to be aware of situations or conditions which demand greater
attention to safety practices when operating or servicing the unit.
WARNING indicates a situation demanding full attention to safety precautions due to possible
hazards.
Segments of information preceded with the word “IMPORANT” should be noted, as damage
may occur to the unit or system if detailed instructions are not followed.
Note: Most Pick Variable Flow Heaters are used to heat water. However, these units also find
extensive service in processing a water-miscible products. Installation, maintenance and
troubleshooting procedures are not affected b the nature of the liquid being heated. (To avoid
complications, this manual uses “water” to refer to any liquid or slurry being heated.)

PICK VARIABLE FLOW SERVICE MANUAL
5
TROUBLESHOOTING
Pick heaters rarely require troubleshooting or repair, thanks to the simplicity of design and
operation. Many apparent difficulties with heater operation are actually the result of a problem or
adverse condition in the steam supply system, or product supply and distribution lines.
The following pages are to direct the technician through a logical approach for system
troubleshooting. General problem are shown in the header of each table. Key physical
observations are listed in the OBSERVATION column. PROBABLE CAUSE is the likely cause
of the problem and ACTION indicates the suggested operation to resolve the problem. The PAGE
column directs the technician to additional service or repaid instructions for the suggested action,
if applicable.
If you are not able to solve a problem with your heater as described in these pages, or if your
problem is not cocered in this manual, please contact your local Pick representative or call Pick
Heaters at [phone]. (Outside the US and Canada, call 262-338-1191 or Fax 262-338-
8489.)
PROBLEM: Heater will not heat liquid to the desired temperature.
OBSERVATION PROBABLE CAUSE ACTION PAGE
Insufficient supply air
pressure
Check air supply, set
filter regulator at 20 psi
Temperature controller
problem
Check temperature
controller components
and air supply. See
separate manual for
optional temperature
controller.
21
Steam control valve is
FULL CLOSED
RTD failure, or polarity on
I-to-P Transducer (+/-) may
be reversed (optional
electronic controller only)
Check wiring for loose
connections, refer to
separate manuals for
wiring diagrams.
Improper controller
calibration
Increase controller
setting and re-calibrate
21
Inadequate air pressure Check air pressure
supplied, set filter
regulator at 20 psi
I-to-P tranducer calibration
(optional)
Calibrate I-to-P per
separate manual
Steam control valve is
PARTIALLY OPEN
Steam valve actuator spring
out of adjustment
Adjust actuator per
separate manual
20
Steam control valves
is FULL OPEN
Water flow is higher than
originally specified
Reduce water flow rate
Check specifications on
heater order, compare
to actual operating
conditions

PICK VARIABLE FLOW SERVICE MANUAL
6
Steam control valves
is FULL OPEN
(continued)
Temperature rise may be
greater than originally
specified
Adjust heater operating
demand to original
specifications. Consult
factory for upgrade to a
different heater or
steam valve if demand
can’t be altered
Plugged steam strainer
basket
Remove steam line
basket, empty debris,
flush basket and re-
install
22
Deposit accumulation on
injection tube
Clean injection tube.
Contact factory for
possible alternate
materials
14
Damaged injection tube Disassemble and
inspect injection tube.
Repair injection tube or
return to Pick Heaters
for complete re-
conditioning.
12-13
Steam boiler or pressure
reducing valve (PRV) set
lower than specified
Increase steam supply
pressure at boiler or
PRV. Consult Pick
Heaters for re-sizing of
steam valve.
23
Steam boiler undersized Confirm boiler output,
and overall steam
requirements.
Steam supply valve NOT
FULL OPEN
Confirm that all steam
supply valves are open
Steam supply piping or
components are undersized
or restricted
-Check for restrictions
in steam supply piping.
-Upgrade supply pipe
size (see “Steam
Supply” section for
steam line sizing
calculations)
See
Installation
Manual
22
Water pressure is too high
Supply pressure higher than
design
Water pressure reducing
valve is set too high
-Install pressure
reducing valve
-Consult factory
-Reduce setting
23
PROBLEM: Heater will not heat liquid to the desired temperature.
OBSERVATION PROBABLE CAUSE ACTION PAGE
Pump not circulating water Inspect and repair
pump as necessary
See parts list

PICK VARIABLE FLOW SERVICE MANUAL
7
Malfunction in the pump
look check valve
Inspect and repair
check valve as
necessary
Capacity of heater is
exceeded
Consult Pick Heaters
for heater upgrade
information
Faulty temperature
controller
Repair or replace
controller
21
Boiler or supply not
adequately sized to provide
enough steam to
accommodate all demands
in the steam system
Check steam supply
sizing and boiler for
pressure fluctuations
22Steam inlet pressure
varies
Steam quality may be poor
(excess condensate
entrained in system)
Install a drip leg with a
steam trap upstream of
the strainer, to maintain
high quality steam at
the heater.
See
Installation
Manual
Steam valve packing gland
too tight
Adjust steam valve
stem packing gland
21 Steam valve has a
jerky motion
Air leak in the control line -Use Soap solution to
detect any leaks
-Repair leaks or replace
line
21
Optional temperature
controller not properly tuned
*(PID Parameters)
Tune the controller per
controller manual.
Injection tube problem
Stuck piston
Plugged Orifices
Broken spring
Refer to detailed
instructions for
disassembly and
inspection of the heater
and injection tube
12-14
Air or gas trapped in a high
point of the supply or the
discharge piping creating an
unstable condition
-Bleed air from the
system
-Remove surge tank
-Install automatic air
vent valve(s) at system
high points
23
Steam valve oscillates
*PID- Proportional
Integral Derivative,
the tuning parameters
on some electronic
and pneumatic
temperature
controllers
Water and steam pressures
too close together
Check operating
pressures
Reduce water pressure
or increase steam
pressure

PICK VARIABLE FLOW SERVICE MANUAL
8
PROBLEM: Noisy Heater Operation.
OBSERVATION PROBABLE CAUSE ACTION PAGE
Air trapped in a high point
of the cold water supply or
the hot water header,
creating an unstable
condition
Bleed air from the
water system
Install automatic air
vent valve(s)
23
Distribution branches not
connected to the top of
water headers
Check connection of
distribution branches,
re-pipe if necessary
or
Add automatic air
bleeds at system high
points
23
USE-POINT control valves
opening or closing too
rapidly
-Readjust rapid-acting
control valves
-Adjust or repair valves
as necessary to allow
smooth operation
-Eliminate sources of
water pressure spikes or
upsets
Cross-connection between
the hot water line and
another water line
-Visually trace all lines
to locate possible cross-
connections
-Eliminate the cross-
connection with
installation of check
valves or other valving
Water and steam pressures
too close together
-Check operating
pressures
-Reduce water pressure
or increase steam
pressure
23
Unstable water pressure
valve in system
-Observe operation of
all valves with steam to
the heater turned off
-Adjust or replace
faulty valves as
necessary
Shock absorber or pulsation
dampener device in the
system
Remove all shock
absorber devices (surge
tank)
Continued next page
Supply water pressure may
be unstable
-With steam off,
inspect water supply
system or pressure, and
correct as necessary
-Install water pressure
control valve if
required

PICK VARIABLE FLOW SERVICE MANUAL
9
Steam quality may be poor
(excess condensate
entrained in steam
-Examine the steam
system, correcting any
deficiencies
-Install a drip leg with
steam trap, upstream of
the strainer, to maintain
high quality steam at
the heater
See
installation
manual
Steam control valve
positioned less than 20%
open (operating below
minimum turndown)
Check steam valve
travel when operating.
Valve must be open
more than 20% open.
Consult Pick Heaters
about a smaller or dual
steam valve
arrangement
21
Steam control valve moves
too fast (only with non-
standard or faulty
temperature controller)
The temperature
controller should be
tuned to allow 7-10
seconds for full valve
travel
Injection tube problem Refer to detailed
instructions for
disassembly and
inspection of the heater
and injection tube.
Replace piston, spring
or injection tube if
required
11-13
Crack or hole in steam flow Repair or replace inlet
house.
CONSULT FACTORY
Steam control valve moves
too fast due to use of valve
positioner(s)
Remove valve
positioner(s)
Steam valve opening
pressure out of adjustment
Adjust valve according
to steam valve
instruction manual
20
Valve packing gland too
tight
Adjust packing gland
according to valve
manual
21
Unstable steam pressure
reducing valve upstream of
the system
Examine reducing
valve, repair or replace
if necessary

PICK VARIABLE FLOW SERVICE MANUAL
10
PROBLEM: Low Water Flow Rate
OBSERVATION PROBABLE CAUSE ACTION PAGE
Supply failure from the
water source
Examine water supply
system, correct all
problems
Broken or plugged pipe
fittings, including check
valves, gate valves, strainer,
etc.
Inspect water supply
lines, replace plugged
or faulty components
Clean water strainer
basket (if applicable)
PROBLEM: Overheated water or steam discharge
OBSERVATION PROBABLE CAUSE ACTION PAGE
Temperature controller set
too high during initial setup,
or during a previous
operating session
Reset controller to the
desired temperature
-See installation
manual for calibration
procedure
Air pressure supplied to the
temperature controller too
high
Reset air pressure to 20
psi
Relief valve not functioning
properly
Inspect adjust or repair
as necessary
19-20
Particularly after
extended heater
shutdown
Lead in the steam control
valve
Inspect and repair as
necessary
20
PROBLEM: Temperature indicator doesn’t agree with controller setting
OBSERVATION PROBABLE CAUSE ACTION PAGE
Water temperature is
stable and satisfactory
Temperature controller not
properly calibrated
Re-calibrate
temperature controller
(See separate manual
for optional controllers)
21
PROBLEM: Discolored Water
OBSERVATION PROBABLE CAUSE ACTION PAGE
Problem in the supply water
system
Inspect water lines,
correct any deficiencies
Galvanic corrosion due to
dissimilar metals (between
heater and system piping)
Install dielectric unions
at all connections
between the heater and
copper piping
23
Problem in the steam supply
system
Examine the steam
supply system, correct
any deficiencies

PICK VARIABLE FLOW SERVICE MANUAL
11
INJECTION TUBE SERVICE
INJECTION TUBE ORIFICES
PLUGGED
The most common cause of this problem is
hard water. When hard water is heated
above 120°F the lime in the water
precipitates out of the water and coats the
injection tube and other surfaces These
deposits can be removed by circulating an
appropriate cleaning agent through the
heater and pump loop.
WHEN TO CLEAN THE PICK
HEATER
How often a Pick heater will require
cleaning depend son the composition of the
water being used, the length of time the
heater is in operation, the quantity of water
heated, and the temperature to which the
water is heated. Because these factors vary
from one application to another, no fixed
rules or schedules are possible. (Pick heaters
may require cleaning once per year, once
each month- or even more frequently).
Periodic inspection is the only sure way to
determine the proper interval between
cleaning.
IMPORTANT- A significant drop in hot
water temperature (below the level the
heater has been producing regularly)
indicates that the Pick heater has internal
lime deposits, and should be cleaned.
OBTAINING THE PROPER
CLEANING SOLUTION
The cleaning solution should be formulated
such that it will not attack copper bearing
alloys, (e.g. brass and bronze), cast iron,
steel or stainless steel. (316SS). Some
descaling agents can cause hydrogen
embrittlement, which may result in injection
tube spring failure, or cracking of the
injection tube. Inhibited dilute muriatic acid
is widely used with satisfactory results.
WARNING: The use of improper
cleaning solvents may result in reduced
product life or even in catastrophic
failure. If the heater is used in potable
water service all cleaning chemicals
should be FDA approved.
TABLE 1- Cleaning Solution Capacity
Heater Model Gallons (approx)
6X7 1
6X10 1
6X25 2
6X50 4
6X75 6
6X100 11
6X150 16-31
6X200 24-53
6X350 31-58
6X500 55-97
Capacity of larger heaters depends on the
size of the associated piping
INTERNAL CLEANING WIHTOUT
DISASSEMBLY
For best results, the cleaning operation
should be undertaken when the internal
lime deposits are wet. If the internal
deposits are allowed to dry before starting
the cleaning procedure, cleaning will be
much more difficult.
WARNING: The resulting
chemical reaction will produce
foaming and gasses,
particularly if it is poured rapidly.
Provide adequate ventilation.
WARNING: Be sure to follow the
manufacturer’s instructions
when handling the descaling
agent. As a minimum, wear
safety goggles ad rubber gloves. A
breathing filter may also be required.
1. Obtain a supply of cleaning solvent
from your local chemical supplier.
SEE TABLE 1 for the approximate
quantity of solvent needed. Follow

PICK VARIABLE FLOW SERVICE MANUAL
12
these steps in sequence to clean your
Pick heater without disassembling
the unit.
2. Close the air supply valve.
3. Turn the pump motor OFF
4. Close the stem supply, water outlet,
and the water supply valves.
5. Drain the heater completely by
opening the drain valves under the
pump and the heater.
6. Remove the pipe plug (or blind
flange on flanged piping) from the
tee above the heater. Remove the
temperature indicator.
IMPORTANT: The open
temperature indicator port will
provide a vent for gasses that may
be formed during the cleaning
operation.
On flanged systems a short stand
pipe must be installed in the
temperature indicator port. It should
extend6” above the top of the outlet
horizontal outlet pipe.
7. Close the drain valves under the
pump and heater.
8. Carefully pour cleaning solvent into
the opening at A. Slowly fill the
heater to the level of this opening.
SEE FIGURE 1.
On flanged units only fill horizontal
outlet 1/3 to ½ full- DO NOT fill
above temperature indicator port.
9. Turn on the pump motor. Allow the
cleaning solvent to circulate in the
heater for approx. 60 minutes,
running the pump motor throughout
this period. The time required to
clean the Pick heater will depend on
how much lime deposit is on and in
the injection tube assembly. A good
indication of when the unit is clean
is the cessation of foaming.
10. Turn off the pump motor. Drain the
cleaning solution into suitable
containers by opening the system
drains. Be sure to follow
manufacturer’s cleaning instructions
for handling, storing or disposing of
the material. Many cleaning agents
can be used more than once before
losing effectiveness. Consult a local
chemical supplier.
11. Reinstall the temperature indicator
and pipe plug (blind flange). Flush
the heater completely by opening
the water supply valve, while
leaving the drain valves open. Turn
on the pump motor. When the water
exiting form the drain valves is
clean and clear, close the drain
valves. Open the water outlet valve.
Open the use point nearest from that
location until the water is clean and
clear. Close the use point valve and
turn off the pump.
12. The Pick heater is now ready to be
returned to service. Please refer to
normal heater startup procedures in
the Installation Manual.
NOTE: The piston in the injection tube
must be free to respond to variations in
steam flow. If restricted, hammer or
vibration will result.
Disassembly is a straightforward and
relatively simple procedure, subject to a few
common-sense precautions. Before
proceeding with disassembly, please read
this entire section carefully to avoid damage
to your heater.
HEATER DISASEMBLY
IMPORTANT: The following parts are
required for proper re-assembly. Make
sure parts are on hand before taking the
unit out of service for maintenance or
cleaning.
SEE FIGURE 1 The body of a Pick heater
(except Model 6X7) consists of two
housings that are flanged together. Before
proceeding, be sure a replacement gasket is
available for reassembly.
If the injection tube is disassembled, new
stainless steel bolts and flexlock nuts will be
required to properly install the spring
stopper. See TABLE 2 for quantity for each
heater model.

PICK VARIABLE FLOW SERVICE MANUAL
13
TABLE 2
Size and QTY of Injection Tube Fasteners
Heater
Model
Bolt Size Quantity
6X7 ¼-28
Shoulder
Bolt
1
6X10 ¼-28 x 5/8 3
6X25 “ 4
6X50 ¼-28 X 3/4 5
6X75 “ 6
6X100 “ 6
6X150 “ 12
6X200 “ 12
6X350 “ 12
6X500 “ 18
HEATER DISASSEMBLY- GENERAL
INSTRUCTIONS
Note: These instructions assume the heater
is installed in the vertical-up flow
orientation.
1. Shut down the heater by closing the
air supply to the temperature
controller.
2. Shut off the pump, and disconnect
the electric power.
3. Close the manual steam supply
valve.
4. Cool the heater if hot, by running
cold water through it. Close the cold
water supply valve.
IMPORTANT: Be sure the steam and
water lines are shut off completely
5. Close the water outlet valve (make a
note of its position when open) to
prevent draining of the distribution
system.
6. Drain all water from the heater by
opening the drain valves under the
pump and heater.
DISASSEMBLY OF MODEL 6X10
THROUGH 6X500
1. Remove the heater housing bolts.
2. Disconnect the union in the
horizontal outlet piping on threaded
units. On welded assemblies remove
the outlet assembly between heater
and outlet valve.
3. Carefully remove the outlet housing,
lifting it straight up until it is
completely clear of the injection
tube. SEE FIGURE 3
CAUTION: The weight of the
outlet housing is listed in the
table shown in FIGURE 1. To
avoid injury, provide mechanical
assistance when handling housing.
IMPORTANT: A minimum clearance
above the heater body at least equal to
dimension ‘D’ in FIGURE 1 must be
available to remove the outlet housing.
Life the outlet housing straight up, using
care to prevent accidental contact
between the housing and the injection
tube during lifting, damage to the
injection tube may result.
REMOVING THE INJECTION TUBE
The injection tube is machined to close
tolerances and is threaded into the inlet
housing. It can be removed with a pipe
wrench or chain wrench. Place the wrench
over the rivets near the threaded end of the
tube. If additional force is required, a second
wrench can be applied over the bolts holding
the spring stopper, at the opposite end of the
tube. SEE FIGURE 3.
IMPORTANT: To avoid damaging the
injection tube, apply the wrench on the
rivet area only. Do not apply the wrench
to the area containing orifices, i.e.,
between the rivets and spring stopper
retaining bolts.
DISASSEMBLY AND INSPECTION OF
THE MODEL 6X7 HEATER
The body of the 6X7 heater consists of a
single housing. See Figure 4

PICK VARIABLE FLOW SERVICE MANUAL
14
1. Disconnect the steam line union
located between the steam valve and
the heater.
2. Loosen the double-end bushing one-
quarter turn, and remove the steam
line nipple to facilitate removal of
the double-end brushing.
3. Unscrew the double-end bushing
from the heater housing and remove
the injection tube assembly if
required. (Most service procedures
can be performed with the tube in
the bushing.)
IMPORTANT: The injection tube is
machined to close tolerances and is a key
component of your Pick heater. It can be
removed from the double-end bushing an
8-inch pipe wrench. Larger wrenches are
not recommended.
IMPORTANT: The proper location for
placement of the wrench is between the
threads and the roll in the tube SEE
FIGURE 4.
INJECTION TUBE INSPECTION (ALL
MODELS)
Inspect the injection tube. If mineral
deposits are evident, clean the tube as
described in Injection Tube Cleaning.
The piston must move freely in the tube.
Use a clean rod, placed in the threaded end
of the tube. Manually move the piston
through is full travel. Work the piston up
and down several times. It must move to the
spring stopper and return smoothly. If the
piston does not move smoothly, proceed
with disassembly ad further inspection of the
injection tube components.
Note: The injection tube assembly can be
returned to the factory for prompt and
comprehensive servicing. Cleaning,
inspection, and repair or replacement of
parts will be performed as necessary to
return the part to original specifications.
Many customers keep a spare injection tube
on hand to minimize downtime during
maintenance.
INEJCTION TUBE CLEANING (ALL
MODELS)
CAUTION: When handling and
using a cleaning solution, be
sure to follow the
manufacturer’s instructions to prevent
personal injury or damage to equipment.
As a minimum, wear goggles and rubber
gloves. The cleaning should be performed
in a location with good ventilation.
It is not necessary to remove the piston for
cleaning if the piston is not stuck. If the
piston moves freely in the tube and no
damage is noted, proceed with cleaning.
Submerge the injection tube assembly in a
container of cleaning solution- (descaling
agent). Refer to OBTAINING THE
PROPER CLEANING SOLUTION
Section, page 11, for recommended cleaning
solutions.
After 30 minutes, flush the injection tube
with water. Inspect the injection tube to
determine whether all the scale has been
removed. BE SURE THE PISTON
MOVES FREELY INSIDE THE TUBE.
If necessary, re-submerge the tube in the
cleaning solution. When all scale is
removed, and the piston moves freely, flush
completely with water. Reinstall the
injection tube assembly, then reassemble the
heater, per the following instructions.
IMPORTANT: Do not leave the injection
tube assembly in the cleaning solution
longer than required. Extended contact
may damage the spring or tube.
INJECTION TUBE DISASSEMBLY
CAUTION: The spring stopper
is under a moderate spring
load. Hand pressure can
restrain the spring force. However, care
should be exercised when removing the

PICK VARIABLE FLOW SERVICE MANUAL
15
stopper during injection tube
disassembly.
DISASSEMBLY (MODELS 6X10
THROUGH 6X500) SEE FIGURE 3.
Remove the nuts and bolts retaining the
spring stopper from the unthreaded end of
the tube. Remove the spring stopper and
spring, and inspect each part for wear or
damage.
Depending on the condition of the injection
tube, it may be necessary to grasp the spring
stopper with a pliers, while lightly tapping
the outside of the injection tube.
IMPORTANT: DO NOT clamp the
injection tube in a vise to perform
maintenance.
DISASSEMBLY (MODEL 6X7) SEE
FIGURE 4.
To examine the piston and spring, remove
the shoulder bolt that holds the spring
stopper in the injection tube. A 1/8” Allen
wrench is required to remove the shoulder
bolt.
STUCK PISTON (ALL MODELS)A
stuck piston is usually the result of
foreign material wedging between the
piston and the tube.
Thoroughly clean the outer surface of the
piston and the inner surface of the injection
tube. Remove any sludge, welding slag or
other foreign material from inside the tube.
If necessary, sue a descaling agent to
remove lime deposits. Refer to the
discussion of cleaning fluids on page 11.
Note: Clean and inspect the steam elbow in
the inlet housing and any other piping where
debris may have accumulated.
Remove any burrs from the piston and tube.
The piston must move freely inside the tube
before reassembly. Scoring of the piston or
injection tube will not cause a problem as
long as the piston moves freely. Remove any
high points cause by scoring.

PICK VARIABLE FLOW SERVICE MANUAL
16

PICK VARIABLE FLOW SERVICE MANUAL
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PICK VARIABLE FLOW SERVICE MANUAL
18

PICK VARIABLE FLOW SERVICE MANUAL
19
REASSEMBLY AND INSTALLATION
OF THE INJECTION TUBE (ALL
MODELS) SEE FIGURE 3
Be sure the inside of the injection tube is
clear of all deposits and foreign material.
Note that, in some heaters, the piston and
spring stopper have the same outside
diameter but are NOT interchangeable. The
piston has a .055” hole in the center of the
flat end, while the spring stopper has a ¼” or
larger hole. Reinstall the piston in the tube
so the pillow or open side of the piston is
facing the spring stopper end of the tube,
allowing the spring to fit inside the piston.
Reinstall the spring and spring stopper.
IMPORTANT: (Model 6X7 only) Install
the spring stopper with the open end over
the spring. The spring stopper will rest
under the shoulder bolt. SEE FIGURE 4
The spring stopper injection tube has scribe
marks (on the end of the tube) that indicate
the proper positioning for alignment of the
spring stopper bolt holes (except model
6X7). Reinstall the bolts that hold the
spring stopper in place, but DO NOT re-use
the old nuts.
IMPORTANT: Install NEW stainless
steel flexlock nuts to insure proper
locking. Replacements can be obtained
from Pick Heaters. SEE TABLE 2. (Page
12)
The model 6X7 injection tube uses a
shoulder bolt to hold the spring stopper in
place. Use a new stainless steel flexlock nut
when re-assembling. SEE TABLE 2
After the injection tube is reassembled,
make sure the piston operates freely. Check
to be sure there is no binding or restriction
in the tube by manually working the piston
through its full travel several times, using a
length of CLEAN rod.
HEATER REASSEMBLY (MODELS
6X10 THROUGH 6X500)
Inspect the inlet housing elbow and
associated piping for lime deposits and
debris. Remove any foreign material.
Examine the threads for damage.
Apply a moderate amount of paste-type pipe
sealant with Teflon to the injection tube
threads.
Note: Sealant must be FDA approved
when heating potable water.
IMPORTANT: Place the wrench over the
rivets, in the same position used when
loosening the tube. Tighten snug, but do
not over tighten. Applying force by using
an extra-long wrench, or by placing a
length of pipe over the handle of the
wrench, is likely to damage the injection
tube.
Examine the gasket surface for cleanliness,
and install a new gasket. Install the outlet
housing.
IMPORTANT: Carefully install the outlet
housing straight over the injection tube.
Avoid contact between the housing and
injection tube.
Reinstall all heater flange bolts and install
nuts finger-tight. Reassemble and tighten the
outlet union. If the union is flanged, clean
the gasket surface and install a new gasket.
Securely tighten all heater flange nuts,
working in a cross (alternate) patter. The
Pick heater may now be returned to
operation.
HEATER REASSEMBLY (MODEL
6X7) SEE FIGURE 4
If injection tube was removed from the
double-end bushing, apply a moderate
amount of paste-type pipe sealant with
Teflon to the injection tube threads.

PICK VARIABLE FLOW SERVICE MANUAL
20
Note: Sealant must be FDA approved
when heating potable water.
Thread the injection tube into the double-
end bushing (the bushing should be clamped
in a vise at the flats to prevent damage to
threads.) Use an 8-inch pipe wrench to
tighten securely. Do not over tighten –
excessive force will damage the injection
tube.
IMPORTANT: To avoid damaging the
injection tube, apply the wrench on the
area between the threads and the roll
only. Applying the wrench to the area
containing the orifices may distort the
tube and result in the piston sticking.
Install the bushing and injection tube into
the housing, using pipe sealant on the
threads. Reinstall the steam piping and
union. Securely tighten all joints. The heater
may now be returned to operation.
PUMP SERVICE
The function of the pump is to provide
accurate temperature control over varying
flow rates. The pump creates a high rate of
water flow through the heating chamber and
over the temperature control sensor. This
permits the temperature controller to track
changing conditions and maintain accurate
outlet temperature regardless of water flow.
BASIC PUMP INSTALLATION
CHECKS
Check the flow direction and rotation of the
pump. The arrow on the pump body should
show flow from the temperature controller
to the heater inlet (normally pumping
down.) Be sure the check valve in the pump
loop is installed to permit flow in this
direction. Check to be sure the coupling is
tight on both the pump and the motor shaft if
so equipped. (Models 6X100 through
6X500.)
CIRCULATING PUMP SERVICE
CAUTION: Be sure the pump
motor is turned off and the
electrical supply is locked out
before servicing the pump.
Close water inlet and outlet, and steam block
valves. Drain water from the heater. Refer to
the pump service sheet for detailed pump
repairs. Completely assembled bearing
housings are available from the factory, if
applicable. (Model 6X100 through 6X500)
RELIEF VALVE FUNCTION
The relief valve has two functions: 1) to
dampen pressure spikes, and 2) to permit
steam to enter the heater during
periods when water is not being
used.
WARNING: The relief valve must be set
to relieve at a pressure between the water
and steam pressures. If the relief valve is
removed, plugged or set above the steam
pressure, overheated water or steam may
be discharged into the downstream
piping. THIS COULD CAUSE DAMAGE
TO THE EQUIPMENT, OR COULD
RESULT IN SERIOUS INJURY. ONE
POUND OF STEAM HAS A VOLUME
OF ALMOST 27 CUBIC FEET WHEN
DISCHARGED INTO THE
ATMOSPHERE.
When water is not being used and all outlets
are closed, the heater and associated piping
become a closed, filled chamber. As the
pump loop cools, the temperature controller
calls for steam to maintain the set
temperature. Initially, steam can not enter
the heater. As the steam valve opens, the
pressure in the heater increases until it
reaches the relief valve setting. At that point
water exits through the relief valve allowing
steam to enter and heat the water in the
pump loop to the set temperature. The
temperature controller then closes the steam
valve.