Johnson & Starley JU156, JU117, JU78 Installation, Commissioning & Servicing Instructions

These instructions are to be left with the User or adjacent to the Gas Meter

JU SERIES WARM AIR HEATERS

INST ALLATION, COMMISSIONING & SERVICING INSTRUCTIONS

JU78: G.C. No 42 417 79
JU117: G.C. No 42 417 78
JU156: G.C. No 42 417 77

These appliances have been tested and certified by B G Technology for use with natural gas.

1. BRIEF DESCRIPTION

1 Air circulating fan
2 Control Panel

11

8

4
7

5

3
9

3 Data plate
4 Limit Switch
5 Multifunctional control
6 Burner and Control Assembly
7 Gas connection
8 Fan Delay Control

9 Piezo unit
1 0 Summer Air Circulation switch
11 Draught Diverter

Publication No. ZZ 602/6

June 2003

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10

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Fig. 1

General Layout Diagram

1.1 JU78, JU117 and JU156 are open-flued, fan assisted Upflow , ducted warm air heaters, the outputs of which are as
follows:

JU78: 23.0kW (82.8MJ/h, 78,500Btu/h)
JU117: 34.3kW (123.4MJ/h, 117,000Btu/h)
JU156: 45.7kW (164.5MJ/h, 156,000Btu/h)

THESE APPLIANCES CONFORM TO BS800

1

6Installation shall be in accordance with the current editions of:-

Building Standards (Scotland) (Consolidation) Regulations.
Building Regulations.
Gas Safety (Installation and Use) Regulations (as amended).
BS 7671 Institute of Electrical Engineers (I.E.E.) Wiring Regulations.
BS 5440 Pt. 1 (Flues for Gas Appliances).
BS 5440 Pt. 2 (Installation of ventilation for gas appliances)
BS6230 Installation of Gas Fired Forced convection Air Heaters for Commercial and Industrial space heating (2nd family
gases).
British System Design Manual “Gas Fired Warm Air Heating”.
Model and Local Authority Bye-laws.
IM/2 Purging procedures for non-domestic gas installations.
IM/5 Soundness testing procedures for industrial and commercial gas installations.
IM/11 Flues for commercial and industrial gas fired boilers and air heaters.
IM/16 Notes on installation of pipework (excluding domestic installations of 25mm and below).

IMPORTANT: STATUTE LAW DEFINES THAT ALL GAS APPLIANCES MUST BE INSTALLED BY
COMPETENT PERSONS, (i.e. CORGI REGISTERED INSTALLERS) IN ACCORDANCE WITH THE GAS
SAFETY (INSTALLATION AND USE) REGULATIONS (CURRENT EDITION). F AILURE TO COMPLY WITH
THESE REGULA TIONS MAY LEAD T O PROSECUTION.

1.2 GENERAL DA T A
JU78 JU117 JU156

Appliance height (excluding air discharge top or swivel heads) 1830mm (72in) 1830mm (72in) 1830mm (72in)
Appliance width 375mm (14.8in) 525mm (20.7in) 675mm (26.2in)
Appliance depth 778mm (30.6in) 778mm (30.6in) 778mm (30.6in)
Appliance weight 110kg (242lb) 140kg (308lb) 220kg (484lb)
Flue diameter 125mm (5in) 150mm (6in) 150mm (6in)
Fuse rating T6.3A T6.3A T6.3A

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2.

2. 1 When a heater is fitted into a compartment, the following minimum clearances must be maintained:

2.1.1 12mm (0.5in ) from rear, and a side fitted with a blanking plate, allowing extra space if a gas supply pipe enters the
appliance from this side.

2.1.2 600mm (24 in) from a side fitted with a louvre side return panel.

2.1.3 230mm ( 9 in ) from the front for combustion air supply.

2.1.4 Consideration should also be given to the space required for the removal and replacement of the filter tray and the
entry of the gas and electrical supplies.

2. 2 For service access, a minimum of 750mm (30ins) is required at the front of the heater. Space must also be allowed, in a
compartment installation, to permit the removal of the heater. Where clearances between the appliance and the
compartment are less than 75mm, the internal surface of the compartment must be lined with non-combustible material.
The compartment must be of a fixed rigid structure.

2.3 IMPORTANT: When the heater is installed in a compartment, the ‘SAFETY’ label supplied with the heater MUST BE

AFFIXED in a prominent position on the INSIDE of the COMPARTMENT DOOR.

3. VENTILA TION AND COMBUSTION AIR

3. 1 When the air heater is free standing or ducted, but in an open area, there must be a adequate supply of air for combustion
in accordance with BS 6230 Clause 12.1.1. The openings should be sited so that they cannot be easily blocked (refer to
BS 6230 Clause 12.1.3).

3. 2 Where natural ventilation is used for compartment or plant rooms, suitable permanent openings at low and high level,
communicating directly with outside air, shall be provided in accordance with BS 6230 Clause 12.1.5.

HEA TER COMPARTMENT AND CLEARANCES (See BS6230)

3. 3 If the installation includes more than one heater, the ventilation requirements of BS 6230 must be observed.

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Position of Air direct

Air Vents from outside

JU78 - High Level 132 cm2 (21 in2)

JU78 - Low Level 264 cm2 (42 in2)

JU117 - High Level 197 cm2 (31 in2)

JU117 - Low Level 393 cm2 (62 in2)

JU156 - High Level 261 cm2 (41 in2)

JU156 - Low Level 522 cm2 (82 in2)

T able 1: Minimum Effective Areas

4. DUCT SYSTEM

(See British Design Manual - Gas fired W arm Air Heating)

4.1 RETURN AIR

4.1.1 If the air heater is installed in a compartment, all return air shall be POSITIVELY ducted from outside the
compartment to the bottom of the unit. It is recommended that the return air duct be not routed directly from the
main occupied area, but from a convenient central area serving the remainder of the building.

4.1.2 The return air system must be constructed of non-combustible material. The flue shall not be run through an area
serving as a return air path. It is extremely important that the correct size of return air grilles and ducting is used.
Return air duct sizes and minimum open areas of return air grilles are as listed in Table 2.

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Applian ce Minimum return air Minimum free area of

duct size Return air grilles

JU78 300mm x 300mm ( 12 in x 12 in ) 1887cm2 (291 in2 )
JU1 17 450mm x 300mm ( 18 in x 12 in ) 2796cm2 (434 in2 )
JU156 600mm x 300mm ( 24 in x 12 in ) 3725cm2 (578 in2 )

Table 2

Minimum Return Air and Free Area

4.1.3 An adequate and unobstructed return air path is essential from areas not served by a directly ducted return and to
which warm air is delivered. All such rooms should be fitted with relief grilles which have a free area of

0.0088m2/kW (1in2/250Btu/h) of heat supplied to the room. The only exceptions are kitchens, bathrooms and
WC.’s.

4.1.4 All duct work in the room or internal space in which the heater is installed shall be mechanically secured, and
sealed with ducting tape.

4.2 W ARM DELIVERED AIR

4.2.1 All duct work, including riser ducts, should be fully insulated with 50mm (2in) fibreglass or similar. If short
extended duct runs are taken below floor level these should be similarly insulated, and in addition wrapped with a
sound vapour proof barrier, and protected from crushing.

4.2.2 The duct system should be carefully designed (as given in the guidelines in the British System Design Manual) to
suit the needs of its specific heating requirements and building layout. The type of duct system, (i.e. radial/
extended plenum/stepped) should be installed using the least number of fittings to minimise airflow resistance.

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5. INSTALLATION REQUIREMENTS

5.1 FLUES (see British Standards BS5440 Pt.1 Flues)

5.1.1 All joints shall be soundly sealed.

5.1.2 The flue should be kept as short and warm as possible.

5.1.3 Sufficient support brackets shall be installed to bear the weight of the total flue system.

5.1.4 The spigot connection of the heater draught diverter will accept internally the spigot end of a non-asbestos flue
to BS567 or twin wall metal flue to BS715 of nominal diameter as specified in para 1.2.

5.1.5 A split collar should be fitted to provide for flue maintenance or inspection.

5.1.6 The flue shall be in accordance with the Building Regulations and British Gas Materials and Installations
specification 3rd edition) with regard to clearance and shielding from combustible materials.

5.1.7 All materials shall be in accordance with local gas region and Building Regulations requirements.

5.1.8 The flue should run as vertically as possible. Horizontal runs should be avoided if at all possible and any
directional change should be as gentle as possible. If there is any doubt about the flue configuration, the
equivalent flue height should be determined (see 5.1.10).

5.1.9 If the appliance to be fitted is a replacement, the old appliance should be checked for signs of spillage prior to
commencement of the installation and appropriate action taken, (i.e. check flue system and renew as necessary).

5.1.10 It is recommended that at least 600mm of vertical flue should be provided from the top of the draught diverter
(for new installations this shall be incorporated into the flue design). However, when carrying out replacement
installations, an existing flue system may be encountered, where the vertical flue above the appliance to the first
bend is less than 600mm. In the first instance, the installer must judge whether this distance can be achieved
practicably by some means. Where this is not practicable, the existing flue system may be used, providing there is
no evidence of spillage from the old appliance (see 5.1.9 above). Every effort must be made, however, to ensure
that the existing flue complies in every other way to BS 5440 Part 1, including the visual inspection, flue flow and
spillage test described in 4.3.2 of the above standard. Flue configurations may be assessed in terms of equivalent
vertical height - details are given in 5.1.11. For air heaters, the minimum equivalent vertical height is 1 metre. The
installer must make a judgement based on his knowledge and experience and the examination and testing
described above as to whether an existing flue system can be used.

Note: Ventilation of the compartment, room or internal space in which the appliance is to be installed must be checked

for compliance with the requirements of BS 5440 Part 2 ( Ref. Section 3 of these instructions) and upgraded as
necessary.

5.1.11 Calculation method for flue sizing: ( from BS 5440: Part 1, Appendix A)

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a. This appendix provides a procedure for estimating whether a given flue design is likely to ensure full

clearance of combustion products.

b. The procedure is based on calculating the ‘equivalent height’ of the flue under consideration, i.e. that

height of the straight vertical circular flue pipe of specific size which will produce the same flow rate as
the flue under consideration. The equivalent height is calculated from the formula:

(Ki + Ko )

e

He = Ha x ____________________
(Ki + Ko)a - KeHa + Sum K

where:

He is the height of the equivalent flue;
Ha is the vertical height of the actual or proposed flue;
Ki is the inlet resistance of the flue;
Ko is the outlet resistance from the flue;
subscript e refers to the equivalent flue diameter;
subscript a refers to the actual or proposed flue diameter;
Ke is the resistance per unit length of the equivalent flue;
Sum K is the resistance (other than the inlet and outlet resistance) of the actual or proposed flue.

Note: K and Sum K are obtained from Table 3. Ko and Ki are obtained from Table 4.
c. Table 3 gives resistance factors for common flue components for use in the formula. Table 4 contains the

appropriate inlet and outlet flue resistances. (The flue is likely to be satisfactory if its equivalent

height exceeds 1m).

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Component Internal Size Resistance Component Internal Size Resistance

(mm) Factor (mm) Factor

Flue Blocks 197 x 67 0.85 per meter 135O Bend 100 mm pipe 0.61 per

231 x 65 0.65 run 125 mm pipe 0.25 fitting
317 x 63 0.35 150 mm pipe 0.12
140 x 102 0.60 197 x 67 0.30
200 x 75 0.60 231 x 65 0.22
183 x 90 0.45 317 x 63 0.13

Pipe 1 0 0 0.78 Raking block Any 0.30 per block

125 0.25
150 0.12 Adaptor block Any 0.50

Chimney 213 x 213 0.02 Terminal 100 mm ridge 2 .5

125 mm ridge 1 .0

90O Bend 100 mm pipe 1.22 per 150 mm ridge 0.48

125 mm pipe 0.50 fitting 100 mm GCI 0.6
150 mm pipe 0.24 125 mm GCI 0.25

150 mm GCI 0.12

Table 3

Resistance factors for use in calculating equivalent heights

Appliance Inlet Flue Outlet

Resistance (Ki) Resistance (Ko)

100 mm dia spigot 2 .5 100 mm flue 2. 5
125 mm dia spigot 1 .0 125 mm flue 1. 0
150 mm dia spigot 0.48 150 mm flue 0.48

Table 4

Inlet and outlet resistance

d. Worked Calculation Example:

A warm air unit with a 100 mm diameter flue spigot, fitted with a pre-fabricated flue system leading to a
ridge tile (refer Fig. 2):

From table 4:

Kia Inlet resistance of actual flue = 2.5
Koa Outlet resistance of actual flue = 2.5
Kie Inlet resistance of equivalent flue = 2.5
Koe Outlet resistance of the actual flue = 2.5

From table 3:

Other resistances of actual flue:
Terminal = 2.5

Pipe bend ( 2 x 0.61) = 1.22
Pipe (4 x 1m @ 0.78) = 3.12
(5 x 0.3m @ 0.78) = 1.17

Sum K = 8.01

Equivalent height :

From the formula

(2.5 + 2.5)
He = 6.2 x ______________________
(2.5 + 2.5) - (0.78 x 6.2) + 8.01

He = 3.793 This flue exceeds 1.0m equivalent height and is therefore satisfactory.

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Ha = 6.2m

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STET T erminal

2 x 300 mm lengths

100 mm dia flue pipe

4.6m

4 x 1000 mm lengths

45O bend
300 mm length

1.6m

Fig. 2

Worked example of equivalent flue height

5.1.12 Where flue blocks are used, builders should ensure that no obstruction is created during erection. The installer
should ensure that the connection flue does not project beyond the internal wall of the flue blocks and that there
is provision for examination and servicing.

5.1.13 Important: Before installing the appliance, carry out a visual check of the flue system as directed in the relevant
section of BS5440 Pt.1, then check the flue performance as follows:-

a. Close all doors and windows in the room in which the appliance is to be installed.
b. Introduce some heat into the flue, using a blow torch or other means.
c. Carry out a flow visualisation check with a smoke pellet at the intended position for the appliance. Ensure

that there is discharge of smoke from the correct terminal only, and no spillage into the room. Smoke
coming out of other than the correct terminal only, or a down draught or ‘no flow’ condition, indicates that
the flue has failed the test, and the appliance shall not be connected until the defect has been found and
rectified, and the test satisfactorily completed.

45O bend

2 x 300 mm lengths

Appliance draught
diverter

5.1.14 An approved terminal should always be used; a ridge terminal or ‘GC1’ terminal is specifically recommended. The
latter should be positioned in a free air space where it is not shielded by any structure. A minimum of 1m (3ft)
from any vertical or inclined roof structure must be allowed for.

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5.1.15 Special consideration must be given to external flues with a view to prevention of condensation and weathering
problems.

5.2 ELECTRICAL

5.2.1 Mains. A single phase 230V 50Hz mains connection from a fused spur, rated at 13A with a double pole switch
for isolation is required for the installation. Location of connections is shown at Fig. 5. Mains may be brought
into the appliance via the electrical entry holes on either side, 600mm above the floor. A cable clamp with 2 self
tapping screws is provided to secure the mains cable adjacent to the entry hole, using the 2 screw holes provided.
All wiring must be to I.E.E regulations for electrical installations, using heat resisting 3 core cable to BS 6500

WARNING: TERMINALS MARKED ‘0V’ ARE NOT EAR TH.

5.2.2 Thermostat and its location.
a. A 24V thermostat which complies with BS 800, BS 3955 and BS 4201 must be supplied and is essential to

ensure close control of the comfort level. An anticipator is located in the thermostat which is rated in
amps. The current rating of the anticipator should correspond with the current rating of the multifunctional
control, (i.e. 0.6A). The anticipator should be checked and adjusted as necessary. Connection to the air
heater is as shown in Fig. 5, using sheathed conductors compliant with BS6500.

IMPORTANT: When a thermostat is fitted to the installation, ENSURE THAT THE BLUE LINK
WIRE between terminals ‘8’ and ‘11’ IS REMOVED.

b. The Thermostat should be located where there is free air circulation approx. 1.5m (5ft) from the floor, and

avoiding the following locations:­i) In a room where temperature is greatly affected by the sun or any other heat source, (e.g. radiant

fire, wall light fittings or TV set).
ii ) Near an outside door or windows, or on an outside wall.
iii) Where affected by warm air ducts, diffusers, waste pipes or the heater itself.
iv) Where subject to vibration.

5.3 GAS (See BS5864 and BS6891)

5.3.1 An independent gas supply pipe from the meter is to be preferred wherever possible. When this is not possible,
the pipe must be capable of taking the complete input of the heater and all other gas appliances being served by
this same pipe. This supply should be suitably sized to conform to British Standards requirements of no more than

1.0 mbar (0.4in wg) pressure drop (See table of discharge in BS6891).

5.3.2 The 3/4 in union gas cock (supplied) must be fitted to the gas inlet of the heater for easy isolation during
servicing. The gas pipe should be so fitted and installed as to be durable, substantial and gas tight. To assist in
determining where a gas connection may not be tight, a leak detection fluid should be applied around the
connection. Under no circumstances should a flame be used to locate a gas leak. Gas entry to the air heater is
through either side to a Rc 3/4 ( 3/4 in BSP. external [taper] thread).

6. COMMISSIONING

6.1 PREPARATION:

6.1.1 Ensure that:
a. Gas and Electrical supplies are OFF.
b. Filter, fan and fan compartments are free from obstructions.
c. All registers or grilles are open and conform to design specifications.
d. Return, relief and ventilation air installations are adequate.

6.2 SETTING OF FAN SPEED:

6.2.1 Remove the fan chamber door and the air filter (if fitted).

6.2.2 Set the Fan Speed selector to 230V for heaters fitted to ducted installations, or 210V for heaters utilizing
discharge heads.

6.2.3 Refit the fan chamber door and air filter (if required).

6.3 SYSTEM BALANCING:

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6.3.1 Set the SUMMER AIR CIRCULATION switch to ‘ON’.

6.3.2 Balance the system to provide required volume proportions at warm air outlets.

NOTE: If system includes ceiling diffusers, air velocities through these should be NOT LESS THAN 1.5m/s (300ft/min),
except for very small rooms (i.e. bathrooms etc.). Outlet faces may require partial blanking in order to achieve this.

6.3.3 Set the SUMMER AIR CIRCULATION switch to ‘OFF’.

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6.4 IGNITION OF PILOT AND MAIN BURNERS:
WARNING: If the pilot light is extinguished either intentionally or unintentionally, no attempt should be made to

relight the gas for a minimum of 3 minutes. Ensure that the Electrical supply, Time Control and Selector switches are set
to ‘OFF’.

6.4.1 Set the Thermostat to the lowest or OFF setting.

6.4.2 On the Multifunctional Control, remove the Outlet Pressure test point cover, and a fit pressure test gauge

(refer fig. 4).

6.4.3 On the Multifunctional Control, remove the Gas Pressure Adjustment cover.

6.4.4 Turn ON the Gas supply to the heater, test for gas soundness and purge the whole gas pipe as described in IM/2

and IM/5.

6.4.5 Referring to Fig. 4, press and hold the OPERATING CONTROL, and whilst observing the Pilot Burner, repeatedly

press the Piezo igniter button until the Pilot burner ignites.
Note: If the Piezo unit should fail to provide a spark, the pilot burner may be ignited by applying a lighted taper to
the pilot burner whilst holding the OPERATING CONTROL depressed.

6.4.6 After 20 seconds release the OPERATING CONTROL and let it spring out; ensure that the Pilot burner remains

alight. If the Pilot burner extinguishes, wait three minutes and repeat steps 6.3.5 and 6.3.6 until Pilot burner
remains alight, holding the OPERATING CONTROL depressed for a longer period than previously.

6.4.7 Ensure that the pilot flame envelops the thermocouple tip, adjusting the Pilot Adjuster as required (refer Figs. 3

and 4).
Note: This appliance uses a low energy pilot burner, which is factory set at 4 full turns anticlockwise from
closed.

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6.4.8 Set the Heater Electricity supply ON.

6.4.9 Set the Time Control to required Heating On periods and the Selector switch to ‘TIMED’.

6.4.10 Set the room thermostat to MAXIMUM.

6.4.11 Ensure that the main burner has now ignited.

6.4.12 Test for gas soundness at the supply, Multifunctional Control, Pilot and Main burners using a proprietary

detection fluid and sealing any leaks found.

6.4.13 Allow heater to operate for a minimum of 15 minutes to ensure stability.

Thermocouple

Electrode

Fig. 3

Pilot Burner Assembly

Pilot Burner

6.5 MAIN BURNER PRESSURE TEST :

NOTE: AIR HEATER BURNERS ARE F ACT ORY SET T O PROVIDE A NOMINAL HIGH PRESSURE OUTPUT AS
DET AILED IN SUB PARA 1.1

6.5.1 Referring to Table 5 and Fig. 4 below, ensure that the pressure test gauge indicates the correct burner pressure,

resetting if required as follows:
a. At the Multifunctional control:

i. Remove the Burner Pressure Adjuster cover.
ii. Set the Burner Pressure Adjuster to provide a pressure test gauge indication for the correct burner

pressure as detailed in Table 5.

iii. Refit the Burner Pressure Adjuster cover.

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2

1. Start button

2. Off button.

3. Burner Pressure adjuster.

4. Outlet Pressure test point

5. Pilot Adjuster

1

5

3

4

Fig. 4

Multifunctional Control

6.6 EXTINGUISHING OF BURNERS AND TEMPERATURE RISE TEST:

6.6.1 At the Multifunctional control press the OFF button and ensure that both the Main and Pilot burners extinguish.

6.6.2 Remove the pressure test gauge from the Multifunctional Control and refit the Outlet Pressure test point cover.

6.6.3 Ignite the Pilot and Main burners and allow to operate for 15 minutes to ensure stability.

6.6.4 With the main burner operating continuously, check that the temperature rise across heater is between 45oC ­55oC, setting the fan speed accordingly, (decrease fan speed to increase temperature rise). The fan speed is
adjusted by selecting the fan speed at the control panel (decrease voltage selection to decrease fan speed).

6.7 AUTOMATIC CONTROLS CHECK

6.7.1 Set the TIME CONTROL to ‘ON’.

6.7.2 Turn the Thermostat slowly clockwise until the Main burner ignites.

6.7.3 Ensure that the fan starts to operate after a short period (approx. 1-2 minutes).

6.7.4 When the temperature reaches the control setting, ensure that the Main burner extinguishes followed by the fan
switching off after a short period.

6.7.5 When temperature falls below control setting, ensure Main Burner re-ignites followed by fan operation.

6.8 SAFETY CHECKS:

6.8.1 Check for gas soundness within the appliance.

6.8.2 Spillage test: Carry out a full spillage test as follows, and ensure that the flue operates effectively with all doors
closed and any extractor fans in operation.

NOTE: If an extractor fan is situated in an adjoining or adjacent room, carry out the spillage test with the interconnecting

doors open.

If the draught diverter is accessible:

a. Introduce smoke into the draught diverter adjacent to an exit from the heat exchanger, by means a smoke

match or puffer.

b. Ensure that there is no spillage present (indicated by displacement of smoke downwards and out of the

draught diverter.

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If the Draught Diverter is not accessible:

a. Introduce smoke, by means of part of a smoke pellet on a non-combustible support, into the heat

exchanger.
b. Extinguish the Main and Pilot burners.
c. Ensure that there is no spillage evident by visually observing the draught diverter location on the air

heater.
d. If spillage is evident, further investigation and rectification is required before re-testing the appliance.

WARNING: The appliance shall not be left connected to the gas supply unless it has successfully passed
the above spillage test.

6.8.3 Turn OFF the gas supply at the service cock and ensure that the Multifunctional Control fail-safe operates within
60 secs (indicated by loud click from Multifunctional Control).

6.8.4 Turn gas supply ON at service cock.

6.8.5 Switch the appliance electrical supply OFF.

6.8.6 Disconnect the fan voltage selector flying lead at the electrical control panel.

6.8.7 Switch the appliance electrical supply ON.

6.8.8 Ignite the Main and Pilot burners as detailed in sub para 6.4.1 to 6.4.8

6.8.9 Ensure that the Limit Switch operates, indicated by the Pilot and Main Burners extinguishing, within 120 and 180
seconds.

6.8.10 Switch the appliance electrical supply OFF.

6.8.11 Reconnect the fan voltage selector flying lead..

6.8.12 Switch the appliance electrical supply ON.

6.8.13 Re-ignite the Pilot burner as detailed in sub-paras 6.4.5 and 6.4.6

6.8.14 Ensure that the Main Burner re-ignites when the appliance temperature reduces, (note: with the fan having been
disconnected, there may be some delay before the Main Burner re-ignites).

JU78 JU117 JU156

kW MJ/h Btu/h kW MJ/h Btu/h kW MJ/h Btu/h
INPUT 29.3 105.5 100,000 43.7 157.3 149,000 58.0 208.8 198,000
OUTPUT 22.9 82.4 78,000 34.3 123.4 117,000 45.7 164.5 156,000
Gas rate cv 2.78m3/h (98.0ft3/h) 4.14m3/h (146.1ft3/h) 5.49m3/h (194.1ft3/h)

1020Btu/ft
Burner setting 12.5mbar (5.0 in wg) 12.5mbar (5.0 in wg) 12.5mbar (5.0 in wg)

pressure (hot)
Main Injector BRAY CAT 33/1250

3

Table 4

Main Burner Pressure Settings

125

100

75

EXTERNAL

JU78,

JU78,

JU117,

JU117,

JU156,

JU156,

50

800 1000 1200 1400 1600

Table 5

Fan Performance Curve

10

AIRFLOW (cfm)

7. INSTRUCTIONS FOR USERS

7.1 If the building is unoccupied, ensure that the Instructions for User are left taped to the air heater for the User, and
Installation Instructions are left at or near the air heater for use on future service calls.

7. 2 If the building is occupied, hand the User Instructions over and ensure the User understands:

7.2.1 How to ignite the pilot and burner.

7.2.2 How to operate the thermostat, time control (if fitted) and heater ON/OFF switches and summer air circulation

switch, and that the time control (if fitted) must be reset following a power failure.

7.2.3 How to extinguish the pilot and main burner at the Multifunctional control, and switch off electrical supply to the

heater.

7.2.4 How to remove, clean and re-fit the air filter (if fitted) and at what intervals (i.e. fortnightly, or weekly for new

premises).

7.2.5 How to control the heating system by opening and closing warm air outlets.

7.2.6 How to obtain summer air circulation.

7.2.7 That the air grilles on the heater or heater compartment; grilles and ventilators in the walls, windows or doors of

the building must not be obstructed.

7.2.8 That the heater must be serviced at least once a year by a competent person to ensure efficient and safe operation.

7.2.9 That the red instructions for safe use have been pointed out and understood.

7.2.10 That expert help must be obtained if persistent failure of the pilot burner occurs.

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8. MAINTENANCE

IMPORTANT: Ensure gas and electricity supplies are isolated before commencing any maintenance or replacement of
components. After completion of any maintenance, always test for gas soundness and carry out a complete functional test of the
appliance in accordance with Commissioning Instructions at Sect 6.1 to 6.8 inclusive.

8.1 ROUTINE MAINTENANCE:

8.1.1 Operate the appliance and check for the correct function of the burner and controls.

8.1.2 Turn OFF the gas and electrical supplies to the appliance.

8.1.3 Remove the air heater front panel.

8.1.4 Remove and check the return air filter/cleaner for cleanliness, remove and clean the Air Circulation fan as

detailed in para 8.9.

8.1.5 Remove the Burner and Controls Assembly as detailed in para 8.2. Inspect and clean the main burner and injector

as necessary. Examine the main burner for cracks, including hairline cracks, exchanging the burner as necessary.

8.1.6 Inspect and clear the pilot burner orifice.

8.1.7 Clean the heat exchanger flueways by thoroughly brushing from above and below .

8.1.8 By viewing through the Fan Aperture, and using a torch or similar, examine the heat exchanger externally for signs

of cracks or holes, particularly around welded joints.

8.1.9 Using a torch or similar, introduce a light source into the heat exchanger burner aperture and upper access port,

and again examine the heat exchanger for signs of cracks or holes, particularly around welded joints, whilst again
viewing through the Fan Aperture.

8.1.10 Refit the Air Circulation fan, Burner and Controls Assembly, and air filter/air cleaner.

8.1.11 Light the appliance and note the main burner flame profile. If the flame profile is affected when the Air

Circulation fan switches on, check for any air leaks between the air heater and the base plenum, paying particular
attention to heaters with rear draught diverters. Rectify any air leaks before continuing with this procedure.

8.1.12 Allow the air heater to operate for approximately 15 minutes to ensure stability, and with the main burner lit,

ensure that the operation of Air Circulation fan does not affect the main burner flame profile.

8.1.13 If no defects are found, fully commission the air heater in accordance with the Installation, Commissioning and

Maintenance instructions applicable to the appliance.

11

8.2 BURNER AND CONTROLS ASSEMBLY REMOVAL:

8.2.1 Ensure that the Gas and Electrical supplies are switched OFF

8.2.2 Remove the appliance central front door.

8.2.3 Disconnect the Multifunctional Control and Limit Switch electrical connections.

8.2.4 Disconnect the gas supply by breaking the union at the input side of the Multifunctional Control.

8.2.5 Remove the 4 x Burner assembly fixing screws and withdraw the Burner and Controls Assembly.

8.2.6 Refit Burner and Controls Assembly in reverse order, ensuring that the Multifunctional Control leads pass
through the grommet on the burner mounting bracket.

8.3 MAIN BURNER ASSEMBLY CLEANING:

8.3.1 Remove the Burner and Controls assembly as detailed in 8.2.

8.3.2 Clean the burner thoroughly both inside and out with a soft brush. DO NOT ENLARGE, DISTORT OR

DAMAGE BURNER HOLES.

8.3.3 Reassemble in reverse order.

8.4 MAIN INJECTORS AND BURNER ARMS, REMOVAL, CLEANING AND REPLACEMENT:

8.4.1 Remove the Burner and Controls Assembly as details in 8.2.

8.4.2 Disconnect the Thermocouple and Pilot Feed Pipe at the Multifunctional Control.

8.4.3 Disconnect the Igniter Lead at the Piezo Unit.

8.4.4 Release the 4 x screws and nuts securing the Burner Assembly, and withdraw the Burner Assembly from the
Burner Manifold.

ZZ602/6

8.4.5 Release the Main Injectors from their housings in the Burner Assembly.

8.4.6 Release the Crosslighting Injector from its housing in the Burner Assembly.

8.4.7 Release the 3 x screw and nuts securing each main burner and the Crosslighting Burner to the mounting plate, and
withdraw each burner.

8.4.8 Release the 2 x securing screws and nuts, and withdraw the Pilot Burner Assembly.

8.4.9 Clean as necessary . DO NOT ENLARGE, DISTORT OR DAMAGE MAIN INJECTOR HOLES.

8.4.10 If the injectors are to be replaced, ensure that they are correctly marked, referring to the Data Badge for details.

8.4.11 Refitment or replacement of injectors or burner arms is in reverse order.
Important: DO NOT OVER-TIGHTEN the Thermocouple connection. Tighten to finger tight + 1 flat.

Burners should be cleaned with a soft brush. Under no circumstance should the burner holes be enlarged,
distorted or brushed strongly. If an injector is replaced, ensure that is correctly marked, referring to Table 4 or
short list of spares. After replacement or refitment of the Pilot Burner, ensure that the gap between the igniter
electrode and the Pilot Burner tip is approximately 3mm, and that the flame profile is correct, adjusting as
necessary.

8.5 PILOT BURNER, THERMOCOUPLE AND ELECTRODE, REMOVAL AND REPLACEMENT:

8.5.1 Remove the Burner and Controls Assembly as detailed in 8.2

8.5.2 Disconnect Igniter lead from Piezo unit.

8.5.3 Disconnect the Thermocouple from the Thermocouple adapter on the Multifunctional Control, taking care to
avoid causing damage to the Thermocouple Capillary.

8.5.4 Release the Pilot Feed Pipe from the Multifunctional Control.

8.5.5 Remove the 2 x 4mm screws securing the Pilot Burner Assembly to the Burner and Control Assembly, and
withdraw the Pilot Burner Assembly.

8.5.6 Release the Thermocouple securing nut from the Pilot Burner Assembly and withdraw the Thermocouple, taking
care to avoid causing damage to the Thermocouple Capillary.

8.5.7 Release the Electrode securing nut from the Pilot Burner Assembly and withdraw the Electrode.

8.5.8 Release the Pilot Feed Pipe securing nut from the Pilot Burner Assembly and withdraw the Pilot Feed Pipe and
Pilot Injector from the Pilot Burner Assembly, and disconnect the Pilot Injector from the Pilot Feed Pipe hook.

8.5.9 Refitting or replacement is in reverse order.

NOTE: When refitting or replacing the Thermocouple, tighten only to FINGER TIGHT + 1 FLAT.

12

8.6 MULTIFUNCTIONAL CONTROL REMOV AL:

8.6.1 Remove the Burner and Controls Assembly as detailed in 8.2

8.6.2 Disconnect the Thermocouple and adapter at the Multifunctional Control, avoiding damage to the capillary.

8.6.3 Disconnect the Pilot Feed Pipe from the Multifunctional Control.

8.6.4 Disconnect the Multifunctional Control input and output supply feeds.

8.6.5 Refitting or replacement is in reverse order.

8.7 PIEZO UNIT REMOVAL:

8.7.1 Disconnect the 2 x conductors from Piezo unit.

8.7.2 Release the Piezo retaining nut and remove the Piezo unit from its mounting bracket.

8.7.3 Refitting or replacement is in reverse order.

8.8 CONTROL PANEL REMOVAL:

8.8.1 Ensure that the electrical supply to the appliance is isolated.

8.8.2 Release the 2 x securing screws and remove the appliance lower front door.

8.8.3 At the Control Panel terminal block, (and referring to Fig. 6), disconnect the following:

a. 230V connections ‘L’, ‘N’ and ‘E’ to the Air Circulating Fan at terminals ‘15’, ‘16’ and ‘17’.
b. 230V mains ‘L’, ‘N’ and ‘E’ connections from terminals marked 230V 50 Hz ‘L’ and ‘N’, and the earth

stud.

c. Thermostat connections from connection block terminals ‘8’, ‘9’ and ‘11’.
d. Multifunctional Control connections from connection block terminals ‘5’ (YELLOW) and ‘7’ (BLACK).
e. Fan Delay Control connections from connection block terminals ‘1’ (BROWN), ‘2’ (BLUE with RED

sleeve) and earth stud (GREEN/YELLOW).

8.8.4 Disconnect the 2 BROWN conductors from the SUMMER AIR CIRCULATION switch.

8.8.5 Whilst supporting the Control Panel, release the 4 securing screws and withdraw the Control Panel from the
appliance, releasing the wiring from cable clamps and grommets as required.

8.8.6 Refitting or replacement is in reverse order.

8.9 AIR CIRCULATING FAN, REMOVAL AND CLEANING:

8.9.1 Ensure that the electrical supply is isolated.

8.9.2 Remove the Control Panel as detailed in para 8.8

8.9.3 Release the securing screw from the upper front flange of the fan skirt, and withdraw the flange.

8.9.4 Release the 2 screws securing the Fan Assembly to the fan chamber floor, and withdraw the Fan Assembly by
sliding it forward, avoiding damage to fan blades.

8.9.5 Remove all dust from impeller and motor, avoiding damage to the fan blades and taking care not to disturb the
balance of the fan..

8.9.6 Refitting or replacement is in reverse order.

8.10 CAPACITOR REMOVAL:

8.10.1 Remove the Air Circulating Fan as detailed in para 8.9.1 to 8.9.4

8.10.2 Release the capacitor from the retaining clip.

8.10.3 Remove the protective cover from the capacitor and disconnect the 2 black conductors from the capacitor
terminals.

8.10.4 Refitment or replacement is in reverse order.

8.11 FAN DELAY CONTROL REMOVAL:

8.11. 1 Ensure that the electrical supply is isolated.

8.11. 2 Remove the appliance central front door.

8.11. 3 Release the 2 x screws securing the Fan Delay Control cover, and withdraw the cover.

8.11. 4 Disconnect ‘LOAD’ (BLUE), ‘COMM’ (BROWN) and EARTH (GREEN/YELLOW) connections from the Fan
Delay Control.

8.11. 5 Release the 2 securing screws and withdraw the Fan Delay Control.

8.11. 6 Refitment or replacement is in reverse order.

ZZ602/6

13

8.12 LIMIT SWITCH REMOVAL:

8.12.1 Ensure that the electrical supply is isolated.

8.12.2 Remove the appliance central front door.

8.12.3 Disconnect the 2 BLUE conductors from the Interrupter at the Multifunctional Control.

8.12.4 Release the 2 x screws securing the Fan Delay Control cover, and withdraw the cover.

8.12.5 Release the 2 x screws securing the Temperature Probe assembly, and withdraw the assembly.

8.12.6 Remove the Temperature Probe from the terry clip, and withdraw the probe from the assembly having first
removed the grommet.

8.12.7 Release the 2 x screws securing the Limit Switch, and withdraw the control from the appliance.

8.12.8 Refitment or replacement is in reverse order.

8.13 HEAT EXCHANGER ACCESS:

8.13.1 Remove the upper and central front doors.

8.13.2 Remove the Burner and Controls assembly as detailed in para 8.2

8.13.3 Release the 4 x securing screws and remove heat exchanger access plate and gasket from the front of the draught
diverter.

8.13.4 Release the nuts securing the baffle retaining plate, and remove the retaining plate and washers.

8.13.5 Remove the heat exchanger baffles.

8.13.6 Reassembly is in reverse order.

ZZ602/6

NOTE: When reassembling, ensure that the baffle is pushed fully home and access cap is fully sealed. In the event of heat

exchanger replacement being necessary, contact Johnson and Starley Service Department.

9. DEFECT DIAGNOSIS

9.1 IMPORTANT: If an electrical defect occurs after installation of the appliance; preliminary earth continuity,
polarity, and resistance to earth checks should be carried out with a multimeter. On completion of any
maintenance/fault-finding task that has required the breaking and remaking of electrical connections, then
checks of continuity, polarity, and resistance to earth must be repeated.

9.2 WARNING: When purging or checking gas supplies, ensure that the ventilation to the room or cupboard is
adequate, and that all naked lights are extinguished.

SYMPTOM POSSIBLE CAUSE REMEDY

a. Pilot will not light. i. No gas supply to heater. Check for gas at inlet pressure test

point on multifunctional control.

ii. Gas supply pipe not purged. Purge gas supply pipe in accordance

with BS 6891.

iii Pilot orifice restricted. Clear pilot orifice or replace pilot

injector.
iv. Piezo system faulty. Check igniter, lead, and electrode.
v. Limit Switch has operated Relight Pilot or replace Limit Switch
vi Limit Switch connections Check connections and wiring.

damaged

b. Pilot lights but goes i. Connection between thermo- Check connection is secure.

out on releasing ST ART couple and Multifunctional
button during initial Control not secure.
light-up, or after
normal operation. ii. Faulty power unit on gas Replace Multifunctional Control.

control.
iii. Faulty thermocouple. Replace Thermocouple.
iv. Pilot flame too small. Adjust.
v. Pilot orifice restricted. Replace Pilot injector
vi. Limit control has operated Relight Pilot or replace Limit Switch.

14

c. Main burner lights i. Loose electrical connection Check connections.

but fan fails to run Fan Delay Control.
after approx. 3 min.

ii. Fan Delay Control set incorrectly. Check for correct settings.
iii. Faulty fan assembly. Replace, taking care not to damage

impeller.
iv. Faulty Fan Delay Control. Replace.
v. Burner pressure setting incorrect. Adjust Burner pressure.

d. Main burner operating i. Gas rate or burner pressure Check gas rate and burner pressure

intermittently setting high. setting.
with fan running.

ii. Temperature rise excessive. Adjust fan speed or gas rate accordingly.
iii. Air filter or return air path Check filter is clean and air path is clear.

restricted.

iv. Excessive number of outlets Open additional outlets.

closed.

v. Spillage of flue gases. Carry out spillage test and rectify.

e. Main burner operating i . Gas rate or burner pressure Check gas rate and burner pressure

with intermittent setting too low. setting.
fan operation.

ZZ602/6

ii. Fan Delay Control set incorrectly. Check for correct settings.

f. Fan runs for excessive i. Fan Delay Control set incorrectly. Check for correct settings.

period or operates
intermittently after
main burner shuts down.

g. Noisy operation. i. Gas pressure too high. Check burner pressure setting.

ii. Noisy fan motor. Replace fan assembly.
iii. Fan speed setting too high. Adjust fan speed.

j. Pilot alight but main i. Mains electrical supply not Check mains supply.

burner not igniting. connected to heater.

ii. Controls not demanding heat Check that time control and

thermostat are operating correctly.
iii. 6.3A fuse failed. Replace. If failure occurs again, check

wiring for short circuits.

iv. Loose connection to thermostat, Check connections.

Limit Switch , time control,
Multifunctional Control
or transformer.

v. Transformer open circuit. Check with test meter and replace

transformer.
vi. Multifunctional control faulty. Replace Multifunctional control.
vii. Limit Switch faulty. Short circuit control and replace if

necessary.
viii. Room thermostat or external Fit temporary loop in heater thermostat

wiring faulty. socket. If heater ignites, external circuit

or room thermostat is faulty.

15

EQUIPOTENTIAL
BONDING POINT

THESE ITEMS IN

BURNER CHAMBER

FLOOR

SUMMER

SWITCH

DIRECT EARTH

POINT

g/y

240V

br

210V

N

18

19 20

240V

FAN

br

br

br

br

br

6.3A

g/y

b

br

b

F

1

L

N

br

FAN

SW

210V
PWR

br

2

b

br

SLEEV E THIS END

DO NOT CONNECT

OV

WARNING

TO EARTH

LINK A

y

4F

24V

NC OV

r

r

P

T

S

GAS

CONTROL

y

br

L

TRANSFORMER

1.6A

24V

FAN VOLTS
SELECTOR

v

y

765

T2

bk

3

b

2

p/r

bk

T4

NC

T1

OV

LINK B

2 CORE CABLE

N/CN/O

1

240V

p/r

y

N/C

N/O

5

4

br

6

br

7

8

br

NC

240V

br

br

br

br

g/y

b

b

17

1615141312111098

NNC

L

FAN
PWR

THESE ITEMS MOUNTED

ON FRONT BULKHEAD

TEMPERATURE

O’HEAT

LIMIT

CONTROL

INTERRUPTOR

UNIT

LIMIT

SWITCH

JU156

ONLY

BUTT

CONNECTOR

y

bk

FAN

CONTROL

AIR

PROBE

24V

GAS

CONTROL

br

OUT

THIS SIDE

b

g/y

IN

3 CORE CABLE

LINKS A AND B

DIRECT EARTH
POINT (DEP)

br

6.3A

br

L

WARNING :

THERMOSTAT

CIRCUIT

IS 24V

NOT MAINS

N

SUPPLY 240V

50 Hz

FUSED 13A

br

N

br

F1

g/y

br

17

FAN

CONTROL

SUMMER

SWITCH

g/y

b

r

br

F2

br

b

A: REMOVE WHEN USING VOLT
FREE TIMED OR MANUA L
SWITCH.
B: REMOVE WHEN USING
THERMOSTAT.

b

16

RELAY

14

FAN MOTOR

U2

Z1

2

240v

br

7

MAIN WINDING

AUX. WIN DING

JU117 & JU156

JU117 C1=7uF

JU156 C1=16uF

6

8

OL

U1

Z2

3

br

1

C1

JU117

AND

JU156

240V

br

210V

L

NC

NC

b

N16

JU78

17

FAN MOTOR

MAIN

g/y

N

AUX

WINDINGS

8uF

br

L

N

15

b

16

NC

CIRCUIT DIAGRAM: JU78, JU117 AND JU156 AIR HEATERS

br

HI

LO

MOTOR

15

FAN

18

19

20

TAP

FAN

24V

JU78

THERMO
COUPLE

GAS

PILOT

MOTOR

y

8

T2

y

6

INTERRUPTOR

y

7

9

AIR TEMP.

PROBE

O’HEAT

LIMIT

CONTROL

UNIT

GAS

CONTROL

bk bk

B

p/r

11
T1

OV

5

LIMIT

SWITCH

JU156
ONLY

A

1.6A

br

L

N

b

p/r

24V

S

0V

v

WARNIN G

7 AND 9 ARE

DO NOT EARTH

r

P

b

T4

Wire colour code where indicated

LABEL REF NO 1000-2205540-02

Fig. 5

JU Series Air Heaters Wiring Diagram

16

ZZ602/6

Fig. 6

JU Series Air Heaters Principle Dimensions

17

10. SHORT LIST OF SP ARES

ITEM G.C. MAKER’S DESCRIPTION JU78 JU117 JU156
No No No

1 JAH82/545 Fan assembly 1

JAH122/545 Fan Assembly 1

JAH163/545 Fan Assembly 1
2 BOS 1 8 58 Filter tray assembly (if fitted) 1 1 1
3 1000-0514840 Limit Switch 1 1

1000-0522200 Temperature Probe Assembly 1
4 U560-0530000 Thermo-Switch Assembly 1
5 BOS 01841 Multifunctional control 1 1 1

SIT Eletrosit
6 E39538 BOS 02397/4 Pilot assembly 1 1 1
7 386 820 1000-0703870 Thermocouple (SIT 0.290.174) 1 1 1
8 386 775 BOS 01970 Electrode 1 1 1
9 397 819 BOS 02394 Electrode lead 1 1 1
10 U780-0700000 Burner and Controls Assembly 1

U117-0700000 Burner and Controls Assembly 1

U560-0700000 Burner and Controls Assembly 1
11 U780-0752000 Main Burner 2 3 4
12 1000-0703720 Main Injector BRA Y Cat. 33/1250 2 3 4
13

BOS 01676/4 Cross Lighting Injector Inter Albion T100 1 1
14 S 00461 Heat Exchanger exchange kit 1

S 00462 Heat Exchanger exchange kit 1

S 00463 Heat Exchanger exchange kit 1
15 384 505 BOS01441 Piezo Unit 1 1 1
16 U560-0504000 Control Panel 1 1 1
17 385 159 BOS 00104 Fan Delay Control Honeywell L4068C 1 1 1
18 1000-0513100 Fuse 6.3A 20mm Quick Blow (BS4265) 1 1 1
18 1000-0513110 Fuse 1.6A 20mm Quick Blow (BS4265) 1 1 1
19 1000-0505850 Relay 1 1 1

ZZ602/6

18

Johnson and Starley prides itself on its ability to supply spar e parts quickly and efficiently. If you have a pr oblem in obtaining a
spare part, please contact Johnson and Starley Spar es Department at the address below .

JOHNSON & ST ARLEY L TD.

T elephone: [phone] Rhosili Road,

Brackmills,

F a x: [phone] Northampton NN4 7LZ