Midco F400-33 User Manual

INSTALLATION AND
SERVICE INSTRUCTIONS

ECONOMITE MODELS

400-33 AND F400-33

Gas Conversion Burners

In the United States, Installation must conform with local codes

or, in the absence of local codes, with Installation of the
National Fuel Gas Code, ANSI Z223.1-1992, or latest edition
available from American National Standard Institute. Further
reference should be made to the recommendation of your
fuel supplier.

In Canada, Installation must conform with local codes or, in the

absence of local codes, with Installation Codes for Gas

Burning Appliances and Equipment, CGA Standard
CAN/CGA 1B-149.1 or 2. When the conversion burner is used

on a Forced Air Central Furnace, the two yellow and black
warning labels in the literature envelope shall be attached in
accordance with Installation Code, CGA Standard CAN/CGA
1-B149, Clause 5.4.4.4. Further reference should be made to
the recommendation of your fuel suppler.

WARNING: Additions, changes, conversions, and service
must be performed by an authorized MIDCO representative,
service agency, or the fuel supplier. Use only MIDCO
specified and approved parts.

INSTALLER: Inform and demonstrate to the

user the correct operation and
maintenance of the gas utilization
equipment. Inform the user of the
hazards of storing flammable liquids and
vapors in the vicinity of this gas utilization
equipment and remove such hazards. Affix
this manual and associated literature
adjacent to the conversion burner.
CODE COMPLIANCE IS THE SOLE
RESPONSIBILITY OF THE INSTALLER.

USER: Retain this manual for future reference.

If other than routine service or
maintenance as described in this manual and
associated literature is required, contact
a qualified service agency. DO NOT ATTEMPT

REPAIRS. An inadvertent service error could
result in a dangerous condition.

SA FE TY INFORMATION TE RM S. The following terms are used to identify hazards, safety precautions or special notations

and have standard meanings throughout this manual. They are printed in all capital letters using a bold typeface as shown below,
and preceded by the exclamation mark symbol:

DANGER: Identifies the most serious hazards which will result in severe personal injury or death.
WARNING: Signifies hazards that could result in personal injury or death.
CAUTION: Identifies unsafe practices which would result in minor personal injury or product and property damage.

WARNING: If the information in these

instructions is not followed exactly, a fire

or explosion may result, causing property

damage, personal injury or death.

Do not store or use gasoline or other

¥

flammable vapors and liquids in the
vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS:

Do not try to light any appliance.

¥

Do not touch any electrical switch;

¥

do not use any phone in the building.

Immediately phone your gas supplier from

¥

another building. Follow the gas supplierÕs
instructions.

If you cannot reach your gas supplier call

¥

the fire department.

Installation and service must be performed
by a qualified installer, service agency or
the gas supplier.

BURNER
MODEL

BILL OF MATÕL
NUMBER

DATE
CODE
WIRING

DIAGRAM

FOR SERVICE CONTACT:

name

address

phone

MIDCO International Inc.

4140 WEST VICTORIA STREET ¥ CHICAGO, ILLINOIS 60646 ¥ [phone] FAX: [phone] ¥ http://www.midco-intl.com

PRINTED IN U.S.A.

8449-84

797

SPECIFICATIONS

1

The ECONOMITE Models 400-33 and F400-33 con­version burners with intermittent spark ignited pilot are
adaptable to most gas utilization equipment, including
gravity and forced circulation furnaces and boilers. They
are particularly recommended for firing horizontal or
downdraft equipment since they need no draft to main­tain a pilot. Power burner design makes them perfectly
suited for oil burner replacement, including rooftop

applications

and indus

trial

system, clothes dryer and/or fireplace is installed in the
building, provisions must be made for an outside air supply
near the heating appliance area. Install permanently open
grilles sized at not less than one square inch free area per
4,000 BTU of burner input. When ventilating through hori­zontal ducts, grilles should be sized at not less than one
square inch free area per 2,000 BTU of burner input. In
any case, the minimum dimension of rectangular air ducts
shall not be less than 3 inches.

■ In Canada, for detailed ventilation requirements, refer to

standard CAN 1-B149.1 or .2 and/or local codes.

AIR DELIVERY (Approximate Air Delivery at Zero Draft)

400-33........................................................85 SCFM

F400-33....................................................146 SCFM

FIRING RATE (NATURAL or PROPANE)

3

MAXIMUM 400-33......................................400 MBH

MAXIMUM F400-33...................................700 MBH

MINIMUM 400-33.......................................185 MBH

MINIMUM F400-33............................ÉÉ.300 MBH

GAS PRESSURE REQUIRED

NATURAL......................................5.0" to 14.0" W.C.

PROPANE....................................11.0" to 14.0" W.C.

TUBE DIAMETER..........................................................4"

TUBE LENGTH..............................................................8"

RECOMMENDED COMBUSTION CHAMBER SIZE

400-33 AT MAX BTU/HR........................10" x 16

F400-33 AT MAX BTU/HR.ЙЙЙЙЙЙ15" x 25"

2

II PREPARATION OF THE GAS

2

UTILIZATION EQUIPMENT

■ Clean the gas utilization equipment combustion cham-

4

ber, heat exchanger interior, and flue connections. Re-

4

move all adhering tars, scale, dirt and soot. Inspect for ac-

4

tual or potential leaks.

4

■ Cement all joints, including those in the heating appli-

ance base and around the door frames, to prevent leakage
into, or out of the combustion chamber.

■ The access or firing door should open easily to relieve

pressure. If positive latches exist, they should be modified
to permit easy opening; a spring loaded door holder is rec­ommended.

1

■ On all boilers, make certain the pressure relief safety

/2"

valve is in good operating condition.

STANDARD VOLTAGE.............120 Volts...........60 Cycle

FLAME SAFETY..........

Electronic Flame Safety with Spark

Ignited Pilot and 100% Shut-Off.

TABLE1 Burner Specifications

1. Standard burners are shipped as NATURAL gas models. A kit is

available for field conversion to PROPANE gas.

2. SCFM = Standard Cubic Feet / Minute.

All Ratings Based on 1000 BTU/Cu. Ft. NATURAL, 2500

3.

BTU./Cu.Ft. PROPANE at Sea Level. Derate burner for altitudes
over 2,000 feet by 4% for each 1,000 feet above sea level.

4. 1 MBH = 1,000 BTU/hr.

One gallon of fuel oil = 140,000 BTU.

III COMBUSTION CHAMBER

A combustion chamber liner is normally required to protect
non-heat transfer surfaces and to provide a radiant bed for
rapid heat transfer to the primary surfaces of the heat ex­changer. In most cases the existing chamber liner can be
used, if in good condition.

■ In the case of wet base boilers, where the entire firing

chamber is comprised of heat exchange surfaces and no
chamber liner was provided for oil firing, a liner is usually
not required for the ECONOMITE. However, a liner or tar­get wall may be necessary if the firing chamber is unusual­ly short, in order to avoid excess flame contact on the heat

PART 1 INSTALLATION

CAUTION: ECONOMITE Burners are not intended
for outdoor installation and must be protected from
excessive moisture. Provide adequate clearance for
service and proper operation.

I VENTILATION

If the former automatic oil burner gave trouble-free opera­tion, it is probable that the heating plant area has suffi­cient infiltration of air for combustion and dilution of flue
gases. Nevertheless, the area must be checked.

■ Open basement or utility areas of normal construction,

without storm windows or tight doors, will generally allow
sufficient air infiltration. However, if the heating plant is
located in a tight or separate room, ventilation to an open
area as described above will be required. Install two per­manently open grilles, each sized on the basis of one
square inch free area per 1,000 BTU (but not less than
100 square inches) of the total input rating of all gas utili­zation equipment in the combined space. One grille
should be located within 12 inches of the ceiling, the oth­er within 12 inches of the floor.

exchanger walls or flueways.

■ If a built up chamber liner is required, use 2,300

mum insulating material.

■ The burner tube, or the stainless steel sleeve that is in-

cluded with the burner, must be sealed air tight into the
combustion chamber opening with refractory material as
shown by Figures 1and 2. The sleeve is preferred as it is
designed to properly locate the end of the tube relative to
the inside wall of the combustion chamber, and to permit
burner removal without breaking the seal.

CAUTION: In no case should the burner tube be
allowed to extend into the chamber proper; it must be
set at least 1" short of the inside surface.

■ Special heat resistant alloy extension tubes and instruc-

tions are available for those applications where the burner
tube is too short to reach the combustion chamber (such
as old-fashioned gravity warm air furnace installations).

WARNING: BURNER CABINET MUST BE MOUNTED IN
ORIENTATION SHOWN IN FIGURES 1 AND 2. ANY OTHER
MOUNTINGS MAY CAUSE A DANGEROUS CONDITION, AND
WILL VOID BURNER WARRANTY AND AGENCY APPROV­ALS. NON-STANDARD ARRANGEMENTS MAY BE AVAILA­BLE FOR SOME MODELS-CONSULT FACTORY FOR DE­TAILS IF REQUIRED.

■ If the heating plant is located in an area of unusually

tight construction, or if an exhaust fan, kitchen ventilation

-2-

¡

F mini-

■ Before permanently setting the burner in place, check

that the main burner casting and pilot ports are free of for­eign materials, and also that the spark electrode assembly
has not been damaged or displaced. See Figure 7.

FIGURE 1 Dry Base Boiler with Combustion Chamber

Liner (Warm Air Furnace Construction is Similar)

■ The Vent Connector shall be as short as possible.

The entire length shall be readily accessible for inspec­tion, cleaning, and replacement.

■ The length of horizontal uninsulated Vent Connector

between chimney and a single gas utilization equipment
shall not exceed 75% of the the height of the chimney
above the connector, or 100% if the Vent Connector is
insulated.

■ The Vent Connector shall be installed so as to avoid

turns or other construction features which create exces­sive resistance to flow of vent gas. It shall be installed
without any dips or sags and shall slope upward at least
1/4" per foot.

■ A manually operated damper shall not be placed in

the Vent Connector or chimney of any gas utilization
equipment.

■ The Vent Connector shall be firmly attached to draft

hood outlets and flue collars. Joints between sections of
connector piping shall be fastened by sheet-metal
screws or other approved means. The Vent Connector
shall be supported for the design and weight of the mate­rial employed to maintain clearance and prevent physical
damage and separation of joints.

■ A draft hood or a barometric draft regulator shall be

installed in the same room or enclosure as the equip­ment ins such a manner as to prevent any difference in
the pressure between the hood or regulator and the
combustion air supply (see Figures 3 and 4). In no case
shall the relief opening of the draft hood or barometric
draft regulator be located at a point lower than the top of
the highest flue passage in the equipment.

■ Gas utilization equipment requiring controlled draft

may be equipped with a listed double acting barometric
draft regulator, If approved by local codes (see Figure 4).

■ A device which will automatically shut off gas to the

burner in the event of sustained backdraft is required. It
shall be of the listed manual reset type and installed and
adjusted by a qualified service technician in accordance
with the manufacturerÕs instructions.

■ Refer to gas utilization equipment manufacturer for

recommended vent connection requirements.

FIGURE 2 Wet Base Boiler with Unlined

Combustion Chamber

IV CHIMNEY, VENT CONNECTOR AND

DRAFT CONTROL

WARNING: The chimney shall be inspected for
unsafe conditions such as deteriorated masonry and
excessive soot or other blockage or potential block­age. Installation must conform with local codes or in
the absence of local codes with NFPA , ANSI Z223.1
latest edition.

WARNING: The vent connector shall not be con­nected to a chimney already venting solid fuel burn­ing equipment, an incinerator or an open fireplace.

■ The Vent Connector shall be made of non-

combustible, corrosion resistant material capable of with­standing the vent gas temperature produced by the gas
utilization equipment and of sufficient thickness to with­stand physical damage.

FIGURE 3 Recommended Locations forDraft Hoods

-3-

FIGURE 4 Location for Barometric Draft Regulators

Figure 3 and 4 : Copyright by the American Gas

Association. Used by permission of the copyright holder.

V ELECTRICAL

CAUTION: Refer to separate wiring diagram in-

cluded with each burner.

Installation wiring and grounding to the burner must con­form to local codes, or, in their absence in the United
States to National Electric Code, ANSI/NFPA No. 70
latest edition; in Canada, to Canadian Electrical Code

Part 1, CSA Standard C22.1

■ Use copper wire not less than 14 gage for line voltage

wiring. Hook up to a dedicated line with an on-off discon­nect switch and a minimum 10 Amp breaker.

■ The frame of the burner should be well grounded. Nor-

mally the piping and/or electric conduit will provide suffi­cient grounding. However, a ground lug is located in con­trol box for positive grounding where insulated pipe
couplings are used or where any doubt exists regarding
grounding sufficiency.

■ Confirm that the polarity is correctÑhot wire to strip ter-

minal L1, neutral L2Ñand that the neutral line is not sub­ject to induced low voltage (check L2 to earth ground)
from other equipment, as that can cause the electronic
flame safeguard to malfunction.

■ Each installation must include suitable limit control(s).

Existing oil burner combination operating and limit con­trols are normally NOT SUITABLE for gas burner use.

■ Connect motors used on forced air furnace fans or boil-

er pumps to a combination limit control and switch.

CAUTION: Label all wires prior to disconnection
when servicing controls. Wiring errors can cause im­proper and dangerous operation. Verify proper opera­tion after servicing.

VI PIPING

CAUTION: The available gas pressure should be
within the limits shown in SPECIFICATIONS section.
Excessive pressure may damage electric valves, regu­lators and manual valves. If the supply pressure ex­ceeds the 14.0"W.C. maximum, a suitable high pres­sure regulator must be installed ahead of the Main
Manual Shut-Off Valve shown in Figure 5.

■ The burner gas supply piping should branch off from

the main line as close to the gas meter as possible. Do
not connect to the bottom of a horizontal section. Use new
black pipe and malleable fittings free of cutting and
threading burrs or defects.

■ Provide a sediment trap, union and 1Ú8" pressure tap in

piping close to burner as shown in Figure 5.

■ Use pipe joint compound approved for use with Liquid

Petroleum Gases.

■ Piping must also comply with your local codes.

■ To obtain the maximum firing rate of 700 MBH, the

NATURAL gas supply piping must be sized to provide a
minimum of 5.0"W.C. pressure (11.0"W.C. PROPANE) to
the inlet of the main safety valve when the burner and all
other gas utilization equipment are on. The pilot regulator
can be mounted in any position, the main regulator
should be mounted upright and in a horizontal run of pipe.

■ If the burner piping must be rearranged because of

space limitation, be sure to carry out the general arrange­ment shown in Figure 5.

■ Run full size pipe or tubing from regulator vent open-

ings to outside of building. Provide no traps in the vent
lines and terminate away from all doors and windows;
also make provisions for keeping rain and foreign objects
from entering the vent piping.

■ When the burner is installed in the vestibule of jacketed

equipment, it is recommended that the Safety Shut ­Off Valve(s) be left adjacent to the burner within the ves­tibule and the Main Manual Shut-Off Valve be installed
outside.

■ When high supply gas pressure is encountered, as in

the case in many industrial plants, the gas line size can be
reduced to allow for a greater pressure drop; however, the
size must be sufficient to deliver burner rating pressure.

CAUTION: High gas pressure supply lines require
the proper pressure reducing regulators. Install two
separate high pressure regulators of the Tight Shut­Off type upstream of the low pressure regulators. One
sized for main gas input, and one suitable for the min­imum flow regulating capacity of the pilot.

■ The high pressure regulators may be substituted for the

low pressure regulators. If high pressure regulators are
used as substitutes, they must be adjustable down to a
minimum of 2.0"W.C. outlet pressure for the pilot and

5.0"W.C. for the main gas. If they are additions they must
be adjustable down to the maximum burner inlet pressure
rating (14.0"W.C.)

DANGER: Explosion hazard.

Do not use oxygen for pressure testing.
An explosion could occur during initial start up.

CAUTION: Because it is difficult to accurately
control pressure during supply pipe leak testing, it is
recommended that all low pressure (14.0"W.C. max.)
components, both main and pilot, be disconnected
during testing. Exposing low pressure regulators and
valves, including manual valves, to pressures over 1/2
PSIG (14.0"W.C.) will cause damage and void all
warranties.

■ When the gas supply line is about to be put into service

it must be rested to insure that it is gas tight. Use air or
inert gas under pressure and test with soap and water or
other liquids to locate leaks.

■ Before gas is turned into the system, a check must be

made to see that there are no open fittings and to make
sure the burner main and pilot manual valves are closed.

■ After checking above, purge the gas line up to the

burner inlet. Purging the air from the gas supply line at
this step will expedite the first light-off.

-4-

PIPE
SIZE

3Ú4

(400-33 only)

1

1 1Ú4

1 1Ú2

2

CAUTION: Purge outside the building. Do not

purge into the gas utilization equipment combustion

TYPE

OF

GAS

Natural

Propane

Natural

Propane

Natural

Propane

Natural

Propane

Natural

APPROXIMATE CAPACITY-MBH

LENGTH OF PIPE

10

20

40

60

100
275
400
500
700
700

300
350
550
700
700

200
250
375
500
700
700

200
300
400
625
600
700
700

225

300

475

450

700

700

NATURAL GAS

BURNER

SPUD

INPUT

DRILL

MBH

SIZE

RE-

185
300

300
400

3

400
540

540

700

11/32
(.343)

25/64
(.390)

7/16

(.437)

SPUD

MOVED

MANIFOLD

PRESSURE

1

W.C.

1.5"

3.5"

2.0"

3.5"

2.0"

4.0"

1.85"

3.2"

2

PROPANE GAS

SPUD

DRILL

SIZE

#21(.159)

#15(.180)

#9(.196)
#3(.213)

#1(.228)

17/64(.265)

9/32(.281)

19/64(.296)

BURNER

INPUT

MBH

185
250

300
350
400

540

625

700

PRESSURE

1

MANIFOLD

2

W.C.

10.0"

chamber.

CAUTION: Do not exceed maximum or minimum

rated capacity of burner model as shown in Table 1.

Capacities shown are for a total pressure drop of

0.3"W.C. For 0.5"W.C. pressure drop, multiply capacity
shown by 1.3 For higher permissible pressure drops,
consult your utility.

TABLE 2: Schedule 40 NPT Pipe-Capacity Chart

VII MAIN GAS SPUD SELECTION

Burners are approved for use with NATURAL or
PROPANE gas and should be used only with the gas

DATA IS APPROXIMATE AND BASED ON Ò0"

OVERFIRE PRESSURE AT SEA LEVEL

1. Input range of spud. Adjust the main regulator to
vary the manifold gas pressure and burner input
within the range shown for a specific spud drill size.
With PROPANE, do not exceed 11.0"W.C. under
any circumstances.

2. Approximate gas pressure at manifold gas pressure
tap.

3. Drill out 25Ú64 spare spud to 7Ú16.

TABLE 3: Spud Capacity and Preliminary Gas Settings.

specified on the rating plate.

■ The gas input should be set at the heating rate

determined by the building heat loss and/or heating plant
survey, but not exceeding the rated maximum input of
the gas utilization equipment or Economite burner.

■ Burners are shipped equipped for NATURAL gas; the

model 400 with a 11/32 drill spud installed, and the F400
with the spud removed. Compare the gas input required
with the spud capacities shown in the spud table and, if
necessary, install the spare spud (see Figure 7).

MANUAL

BALL VALVE

DRIP

LEG

MANUAL PILOT VALVE

MAIN REGULATOR

VENT

PILOT REGULATOR

MAIN AIR

CONTROLLING SHUTTER

(COUNTER CLOCKWISE

TO OPEN)

MAIN

REGULATOR

FIGURE 5 Piping Connections

MAIN AND

REDUNDANT MAIN

GAS VALVES

-5-

BLOWER MOTOR

BALL VALVE
TEST COCK

PILOT TUBING

"PEEP" SIGHT

PILOT SOLENOID

PILOT TEST TAP

MAIN TEST TAP

PILOT AND AIR TUBE

FLAME
SAFEGUARD
CONTROL

SPARK GENERATOR

PRIMARY AIR ADJUSTMENT

VIII INITIAL START UP AND ADJUSTMENT

WARNING: Ignition is automatic. Make spark
observations into combustion chamber only with
Main and Pilot Manual Shut-Off Valves closed. Con­firm that gas utilization equipment does not contain
any accumulated gases. Purge as described below.

CAUTION: Cover plates, guards, and enclosures
must be maintained in place at all times except dur­ing maintenance and service.

1. Check the piping and valves for gas leaks. Apply

a weak liquid soap solution to unions and joints with
the gas supply on. Leakage will be indicated by
the appearance of soap bubbles. Locate and
correct all gas leaks before proceeding.

WARNING: DO NOT USE OPEN FLAME

2. Make sure that the burner main and pilot gas lines

are completely purged of air. Do not purge into the
combustion chamber.

3. Make sure the burner power switch is off, Main and

Pilot Manual Shut-Off Valves are closed, and motor
is free to rotate. Reset flame safeguard and all limit
controls.

CAUTION: Make sure that the capacity range
of the installed spud and the combustion air­shutter setting are suitable for the gas utilization
equipment. Refer to Section VII and Table 2.

4. Turn on the burner power switch, and allow motor to

run through the pre-purge and ignition cycle. Check

the blower wheel for proper rotation. After a short

run, the flame safeguard will lock out, stopping

the motor. Wait one minute, then reset flame

safeguard.

5. Turn on pilot manual shut-off valve. With Main

Manual Shut-Off Valve still closed, turn on main line

switch. Motor will start. When pre-purge period has

elapsed, flame safeguard will energize pilot solenoid

valve and ignition transformer. Quickly observe pilot

flame.When flamerod senses pilot flame, the

flame safeguard will energize the main valves.

No main flame will occur due to closed Main

Manual Shut-Off Valve. Set pilot pressure to

achieve the largest stable blue flame with a base

that burns firmly within the pilot tip. The best

operating pressure is usually about 3.5"W.C.

Natural (2.25"W.C. Propane). If pilot fails to light see

sections IX and XI.

6. Test for ignition and stability. Cycle the burner

several times with both open and closed air shutter.

Ignition and flame safeguard response will be

prompt with a good flame. Check flame following the

instructions provided by the flame safeguard

manufacturer.

WARNING: Repeated unsuccessful attempts to
light may result in accumulated gases in gas utiliza­tion equipment and chimney. To prevent these gas­es from reaching an explosive level, periodically
purge the gas utilization equipment and chimney as
described above.

7. Check operation of the electronic flame detection

circuit by turning off the pilot manual valve with pilot

burning and Main Manual Shut-Off Valve still

closed. The circuit to the main automatic pilot valve

should be broken immediately.

8. Turn off line switch to stop the burner. Reset flame

safeguard. With On-Off burners, lock air shutter

wide open. On modulating burners, remove wires of
modulating controller from and "W" terminals on
the modulating motor and jumper terminals "R-B" to
drive input adjuster to high fire position when
energized. On 2-step burners, jumper terminals "3­4" on valve actuator valve will open to high fire
position when energized. main flame ignites. Slowly
continue opening the Main Manual Shut-Off Valve to
the wide open position when energized.

9. To make a preliminary setting of the burner input,
determine the manifold gas pressure required from
Table 3 and adjust the main gas pressure regulator
accordingly. See Section XI.

10. To determine the firing rate for NATURAL
gas, accurately time test dial for the number of
seconds for one revolution and use the following
formula. All other gas utilization equipment must
be off.

3600 x test dial size x BTU value

no. of seconds for one rev. test dial

Then divide by 1,000 for MBH value.

Example: 3600 x 1 x 1000

10

11. Adjust combustion air shutter to provide a quiet, soft
blue flame with well defined orange and yellow tips
for NATURAL gas or with well defined yellow tips for
PROPANE gas.

12. The primary air adjustment which affects the flame
length has been set wide open for average
conditions. Decrease the primary air if a longer,
softer flame is desired.

13. Check the operation of the burner; start and stop it
several times with the thermostat or operating
control.

14. With the burner running, check the operation of all
limit and associated controls.

15. PERFORM THE FOLLOWING FINAL
ADJUSTMENTS for combustion and flue gas
temperatures. Take the flue gas samples and
temperature immediately ahead of the draft control.
A. The flue gas temperature should be above

325¡F but not exceeding 550¡F. Excessive flue
gas temperatures will result in low efficiencies.
Low flue gas temperature may cause excessive
condensation. Reset gas input if necessary to
adjust stack temperature.

B. Make the final setting of the combustion air

shutter by checking the flue gases with an
ORSAT or similar combustion testing instrument.
The carbon monoxide content should conform to
local codes, or, in their absence to the level
specified in the Unites States or Canadian
Standard referenced on the front cover of this
manual. The carbon dioxide content should
be approximately 9.5% for NATURAL and

12.1% for PROPANE, or within the limits
prescribed by local codes.

16. Check the draft control to make sure there is no
spillage of flue products into the room.

= 360,000 BTU/Hr. = 360 MBH

= BTU/Hr.

-6-

After the initial start-up procedure, the following steps
can be followed for routine start-up and shut-down on a
seasonal or extended basis.

BURNER START UP

1. Make sure burner power switch is off.

2. Set controller to call for heat.

3. Open firing door.

4. Open Main and Pilot Manual Shut-Off Valves.

5. Reset flame safeguard.

6. Turn on burner power switch.

7. Close firing door after main flame ignites.

8. Reset controller to desired setting.

BURNER SHUT DOWN

1. Turn off burner power switch.

2. Close Main Manual Shut-Off Valves.

3. Close pilot manual Shut-Off Valves.

PART 2 SERVICE

DANGER: Do not tamper with the unit or con­trols. If trouble occurs contact the installing con­tractor, service agency, or fuel supplier. See front
cover.

WARNING: Be sure that the main and pilot
manual Shut-Off Valves are closed and the burner
power supply is turned off before removing any
parts for service.

CAUTION: Cover plates, guards, and enclosures
must be maintained in place at all times except dur­ing maintenance and service.

IX PILOT

The pilot is of the premix, blast type. The full force of
blower air is brought into the mixing tube where the prop­er amount of gas is added through the pilot orifice. This
mixture is discharged through the pilot which contains a
perforated flame retention plate. The outer holes di­verge to spray the mixture against the side wall of the pi­lot tip to provide flame retention. The mixture through
the center port provides the flame that contacts the
flame detection rod and also ignites the main gas.

■ Surrounding the base of the pilot flame is a conical

shroud which protects the flame against extraneous air
currents and inhibits "blow-off" from an overly rich flame.

NOMINAL BTU/Cu. Ft. Hr.

NATURAL 1000ÑPROPANE 2500

APPROX.

CAPACITY

BTU/Hr.

2500

7000

MODEL

400-33

F400-33

ORIFICE

DIAMETER

DRILL #68

.031 DIA.

DRILL #55

.052 DIA.

TABLE 4: Pilot Specifications

CAUTION: Do not indiscriminately increase pilot
orifice size. Pilot troubles are rarely cured in this
manner and new troubles may be created.

■ The pilot gas orifice is the same size for both natural

and propane gas, consequently the gas pressure re­quired for propane is lower than that required for natural
gas. Under normal conditions, with a slight negative

pressure in the combustion chamber, pilot operating

PILOT GAS PRESSURE

NATURAL

2.5"-4.0"W.C

PROPANE

.

2.25"-3.5"W.C

pressures are 3.5"W.C. NATURAL gas and 2.25"W.C.
PROPANE.

■ Some conditions which may require a change from

the normal setting include: extremely long tubing con­nections between the regulator and pilot solenoid, high
negative or positive combustion chamber pressure, actu­al air shutter setting and altitude extremes.

■ Do not subject the pilot to an inlet pressure over

14.0"W.C. See section VI PIPING for high pressure gas.
Note that the standard pilot pressure regulator is not a
tight shut-off and, during standby, the outlet pressure will
build up to the full inlet pressure.

■ The spark rod is located on the center line of the pilot

and is positioned so the high tension voltage will arc to
the inside of the center port of the retention plate (see
Figure 7).

■ The flame rod must be positioned as shown in Figure

7 so that the flame safeguard will detect a proper flame.
Note that it is slightly above the centerline of the pilot.

■ Both the spark and flame rods are currently carrying

conductors and, along with their connecting wires, must
be kept free of contact with conductive metal parts of the
burner. Rod insulators and wire insulator should be
clean, dry and free of cracks.

■ Rods are made from heat resistant alloys and can be

expected to have a long service life. They should be rou­tinely inspected, however, for corrosion or loss of metal.

■ The pilot air tube must be kept free of kinks or inside

obstructions and its inlet end must be positioned per Fig­ure 7, otherwise air flow could be reduced and adverse­ly affect the pilot flame.

X MOTOR, BLOWER INTERLOCK &

CENTRIFUGAL ACTUATOR

CAUTION: BEFORE SERVICING, mark with a
scribe line or measure position of combustion air
controlling shutter, so that it can be reset to its origi­nal position following servicing.

The blower, which is driven by the motor, functions to
supply a constant and dependable source of combustion
air. A centrifugal actuator is mounted on the blower
wheel and, through the interlock switch, proves blower
operation on every run.

■ Cleaning of the blower wheel is usually the only ser-

vice required. Need for cleaning is indicated if the air
cage assembly shows an accumulation of dust and lint,
or if the character of the flame indicates a deficiency of
air. Motor cooling air vents if present should also be
cleaned at this time.

■ The blower side plate, motor and wheel are removed

as an assembly. Disconnect the motor wires, and con­duit then remove the side plate screws.

■ Unless the blower wheel location has been disturbed,

a replacement switch and bracket assembly will assume
the correct position when mounted. Confirmation of the
correct assembly can be made by measurement and
test.

■ A) With the switch assembly unmounted, insert a

probe through the blower opening and push actuator
disk inward as far as it will go. Mark the depth of inser­tion on the probe and measure. Measure the portion of
the switch plunger (unrestrained) protruding past the
bracket arms. The probe insertion measurement should
exceed the switch stem protrusion by at least

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1

Ú16".

■ B) Insert the switch stem through the blower opening

until it just contacts the actuator disk. Then push in slow­ly. The switch should "click" and the actuator spring

should compress approximately 1Ú8" before the bracket
arms are seated. If conditions A and B are not met reset
switch location in the mounting bracket.

■ In both cases above check the results with an electri-

cal continuity test. The circuit across terminals C and NC
should be open when the blower is idle and closed when
the blower is running.

■ When shaft location of blower wheel is disturbed, re-

assemble with a 1Ú16" clearance as shown in Figure 6.

XI GAS PRESSURE REGULATOR

The main gas pressure regulator is used to automatically
reduce and maintain constant gas pressure at the burn­er. The regulator furnished as standard is suitable for a
maximum inlet pressure of 14.0"W.C. The springs in­stalled provides for an adjustable outlet pressure range
of 2.0" to 5.0"W.C. and are factory set for 3.0"W.C. This
regulator is not of the Òtight shut-offÓ type and, conse­quently, when the burner is on standby, the outlet pres­sure will build up to equal the full inlet line pressure. Out­let pressure settings must be checked while the main
gas is flowing.

■ To adjust the outlet pressure, remove the seal cap for

access to the adjusting screw. Turning the screw clock­wise will increase outlet pressure, counter-clockwise will
decrease outlet pressure.

■ When the gas supply pressure is over 14.0"W.C.,

special regulators are required. See Section VI.

■ The vent in the upper diaphragm case normally

breathes only air, but must be connected to the outside
air to prevent escape of gas into the building in case of a
ruptured diaphragm. The vent line must be of sufficient
diameter, otherwise the restriction of air flow may cause
sluggish opening of the regulator. The effect can be
checked by comparing main flame start-up time with the
vent line connected and disconnected. The vent must

never be connected to the burner combustion cham­ber.

■ When the regulator is to be installed, or replaced take

care not to crush the body casting. Apply wrench only to
the heavy body section adjacent to the pipe thread.

XII SOLENOID GAS SAFETY VALVES

(Main and Redundant Main; Standard Construction.)

When the valve operators are electrically energized the
plungers lift the valve disk off the valve seats, allowing
gas to flow. When the current is broken the valves close.
They will normally require no service. However, dirt or
foreign matter on the valve seats could cause leakage.
If leakage is detected or if the operator malfunctions re-

place the entire valve. After replacement check for leak­age. If the valve is removed from the piping do not use
the operator assembly as a lever to turn valve. Apply
wrench on the valve body flat adjacent to pipe being re­moved.

XIII OPTIONAL MOTORIZED MAIN

AUTOMATIC VALVE

(Employed with Redundant Solenoid Valve.)

■ Motorized Main On-Off, 2-Step, and Full Modulating

Valves, are available on special order. The redundant
and solenoid valve may be omitted if the motorized valve
includes optional "Proof of Closure Switch".

■ When the actuator is energized, hydraulic fluid is

pumped from a reservoir to a metal bellows. The bellows
transfers the resulting pressure through the drive stem to
open the valve. A separate spring return drive arm
operates the blower shutter.

■ For general service, the valve should be checked for

operation. The valve actuator may be removed from the
valve body, however, do not disassemble actuator; if
malfunction occurs, replace entire actuator assembly.
The valve body is also not field reparable. If leakage is
detected the entire valve body must be replaced.

XIV FLAME SAFEGUARD

WARNING: Explosion hazard. Do not use any

electronic device if it gets wet. It can malfunction
and cause serious injury or death. Replace any
device that has been wet.

■ Standard F400-33 and 400-33 burners are equipped

with a Honeywell RM7895 microprocessor based burner
control, employing a flame rectification system of flame
detection. Burner construction for special codes and/or
insurance requirements such as Factory Mutual or
Industrial Risk Insurers (IRI) may require alternate
controls. (Refer to Section XV Special Equipment). A
safe start and run control sequence is provided with
instantaneous response to presence or loss of flame
signal. Flame failure response time is 3-seconds.; Pilot
Flame Establishing Period (PFEP) is field selectable
from 4 or 10-seconds. The RM7895 features a pre-purge
time (30-seconds for ON-OFF, 90-seconds for 2-Step or
Modulating burners), and a plug-in amplifier. An airflow
circuit is also field selectable to allow either lockout or
recycle upon loss of airflow. Five LEDÕs (light emitting
diodes) are provided to display sequence information.
Refer to the Honeywell RM7895 literature for detailed
operating information, configuration requirements,
testing, and service.

FIGURE 6 Motor, Blower, and Interlock Assembly

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INITIATE ("POWER" LED is lit).

■ The RM7895 enters the INITIATE sequence when it is

powered. The INITIATE sequence lasts for ten seconds
unless the voltage or frequency tolerances are not met
(refer to Honeywell RM7895 literature for criteria). When
tolerances are met, the INITIATE sequence will restart. If
the conditions not corrected and the hold condition exists
for four minutes, the RM7895 will lock-out. Causes for
hold conditions in the INITIATE sequence are in the
Honeywell RM7895 literature.

STANDBY ("POWER" LED is lit).

■ The RM7895 is idle in this state of sequencing. When

the burner switch, limits, operating limit controls, and all
microprocessor monitored circuits are in the correct state
for the RM7895 to continue, sequencing will advance to

PREPURGE.

PREPURGE ("POWER" LED is lit).

■ The RM7895 in this application features a prepurge

time of 30-seconds for ON-OFF, 90-seconds for 2-Step
or Modulating burners.

■ Once the STANDBY sequence has a "CALL FOR

HEAT" input, normal start-up prepurge will be initiated.

A. The blower motor is powered to start the prepurge

sequence.

B. The airflow interlock switch must close in

ten seconds of prepurge or within the specified
purge card timing. Otherwise a recycle to the
beginning of prepurge or lockout will occur,
depending on how the airflow switch selectable
jumper is configured. Refer to Honeywell
RM7895 literature for configuration requirements.

IGNITION TRIAL

1. PILOT FLAME ESTABLISHING PERIOD (PFEP)
A. The pilot valve and spark generator are

energized.

B. Flame must be proven by the end of the 4 or

10-second PFEP to allow the sequence to
continue. If flame is not proven by the end of
PFEP, a safety shutdown occurs.

2. MAIN FLAME ESTABLISHING PERIOD (MFEP)

■ After the ignition trials, and with the presence of flame,

the main valve is energized. ("MAIN" LED will be lit.) If a
flame-out occurs, the RM7895 will lockout or recycle
within 3-seconds, depending on "jumper" configuration.
Refer to Honeywell literature for proper configuration.

RUN

■ The RM7895 is now in RUN mode and will remain in

run mode until the controller input opens, indicating that
the call for heat has been satisfied or a limit has opened.
Once this occurs the RM7895 will sequence back to the
STANDBY mode.
Notes: 1. During STANDBY and during RM7895

sequencing the "POWER" LED will blink
every four seconds. This is normal.

2. The "ALARM" LED will be lit in the event of

any flame failure.

3. To maintain proper operation of this device

in MUST be electrically grounded. Refer to
Honeywell RM7895 literature for criteria.

XV SPECIAL EQUIPMENT (OEM VERSIONS)

Special equipment, either factory or field installed,
can cause variations in the procedures and descriptions
given in this manual. Generally, any burner ordered with
special factory installed equipment will be supplied with
the appropriate wiring diagram and related instruction
manuals from the special equipment manufacturer
Consult these manuals to identify any differences in
construction, operation, and testing. Field installed
special equipment is the responsibility of the installing
contractor.

FIGURE 7 General Assembly

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TROUBLE CHART

MAKE SURE THE THERMOSTAT AND OPERATING CONTROLS ARE CALLING FOR HEAT.

CAUTION: If a test indicates an electrical component may be defective, before

replacing it, make sure that its associated wiring is not at fault.

1. MOTOR WILL NOT RUN.

A. No current.
B. Defective or misadjusted limit or thermostat.
C. Flame safeguard control on lockout.
D. Defective flame safeguard control.
E. Motor overload out.
F. Defective motor.

2. MOTOR RUNS, PILOT WILL NOT LIGHT, FLAME
SAFEGUARD LOCKS OUT.

A. Air in pilot gas line.
B. Low gas pressure.
C. Clogged pilot orifice.
D. Pilot regulator misadjusted or defective.
E. Defective spark electrode or spark generator.
F. Defective high tension wire.
G. Wrong pilot orifice.
H. Defective pilot valve.
I. Pilot air tube clogged.
J. Incorrect spark gap.
K. Pilot regulator vent clogged.
L. False flame signal; flame safeguard

control.

M. Defective flame safeguard.

3. MOTOR RUNS, PILOT WILL NOT LIGHT, FLAME
SAFEGUARD REMAINS "SET."

A. Defective centrifugal actuator.
B. Defective blower interlock switch.
C. Slow motor.
D. Defective purge timer.
E. False flame signal.
F. Defective flame safeguard.

4. PILOT LIGHTS, NO MAIN FLAME, RELAY
LOCKS OUT.

A. Poor pilot flame adjustment.
B. Clogged pilot air tube.

C. Defective flame rod or wire.
D. Flame rod mislocated.
E. Spark interference.
F. Pilot regulator vent clogged.
G. Defective plug-in amplifier.
H. Defective flame safeguard.

5. PILOT LIGHTS, NO MAIN FLAME, RELAY
REMAINS "SET."

A. Defective main gas valve.
B. Closed leak test cock.
C. Low gas pressure.
D. Grossly misadjusted main gas and air.
E. Defective flame safeguard.

6. SPASMODIC START.

A. Loose wiring.
B. Low gas pressure.
C. Poor pilot flame adjustment.

7. SHORT FLAME.

A. Wrong main orifice.
B. Low gas pressure.
C. Air shutter misadjusted.
D. Main regulator misadjusted.
E. Test cock partially closed.
F. Main regulator vent clogged.

8. LONG HAZY FLAME.

A. Wrong main orifice.
B. High gas pressure.
C. Dirty blower wheel.
D. Air shutter misadjusted.
E. Main regulator misadjusted.

9. GAS FAILS TO SHUT OFF.

A. Dirt on valve seat(s).
B. Defective main valve(s).

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