Powrmatic DHM User Instructions

Users Instructions

WARNING: THIS APPLIANCE MUST BE EARTHED

CE

£1.00 When supplied separately.

DHM Range Issue 1 July 1999

The DHM Range

1. Lighting the Module

NOTE: On initial lighting of th e module , it may take

some time to purge the intern al pipework o f air.
If it is not possible to light the module after
several attempts contact the local service
company.

1. To Start the Module

1.1 Follow the start up instructions for the duct
heater or air handling unit.

1.2 When all external and internal controls are
calling for heat the burner start-up sequence
will commence. The exhaust fan will run and
after a pre-purge period of approximately 30
seconds an ignition spark will be gener ated at
each burner.
The main gas valves will open an d th e burn er s
will be established

NOTE: If any burner fails to establish it will go to

lockout and the lock out indicator / r eset button
on that burner control box will be illuminated.
To restart the burner push the lockout reset
button.

If a burner will not light after four or five
attempts then shut down the unit and call in
a service engineer.

NOTE: If there is loss of flame sign al at an y burn er

during normal running the control box will
immediately initiate spark ignition. If the burner
fails to relight it will go to lockout.

2. To Shut Down the Module

2.1 For Short Periods:

Follo w the in stru ction s pr ovid ed with th e du ct
heater or air handling unit so that external
and/or internal controls are not calling for
heat.

2.2 For Long Periods:

Complete 2.1 above, wait approximately 4-5
minutes for the exhaust fan of the module to
stop running and then turn OFF the gas and
electric supplies to the module.

3. Description of Operation

Important: All heaters must be controlled by the
fitted external control s and n ot b y u se of th e main
switch in the electrical supply to the heater.

The burner start up sequence will commence

each time that the external controls call for heat.
The exhaust fan will run and after a pre purge
period off approximately 30 seconds an ignition
spark will be generated at each burner. The main
gas valves will be opened and the burners
established. When the e xternal control s are satisfied
the burners will be turned off and approximately
4 - 5 minutes later the exhaust fan will be
automatically stopped.

4. Limit Thermostat

The limit thermostat is mounted towards the top
of the module inner panel.

i) Limit Thermostat Reset
In the even t of a f ault that cau ses th e temperatur e
of the air within the module to rise significantly
e.g. Blocked air inlets, the limit thermostat will
operate to shut down the burners. Remove the
cause of the f ault, wait 10 minutes and then reset
the thermostat by pushing the red reset button
(Refer to Figure 1 ). If the limit therm ostat continues
to operate call a service engineer.

5. Maintenance

Regular servicing is essential t o main tain efficient,
reliable and safe operation of the module. Users
are strongly recommended to have the module
serviced at least annually and preferably at the
end of the heating season.

6. IMPORTANT

Free access mu st be main tained to and around th e
module for servicing purposes and the air supply
to the heater must not be restricted in any way.
Combustible materials m u st n ot be st or ed a dja cen t
to the module or the unit it is fitted into.
If at any time a gas l eak is su spected turn OFF th e
gas supply - DO NOT USE A NAKED FLAME - and
contact the local gas undertaking immediately.

PUSH TO

RESET

PUSH MAN

PULL AUTO

Honeywell

Red

reset

button

Fig 1. Limit Thermostat

Every effort is made to ensure accuracy at time of going to press. However as part of our policy of continual product improvement, we reserve the right to alter specifications without prior notice.

HEATING DIVISION

Winterhay Lane

Ilminster, Somerset TA19 9PQ

Tel: [phone] Fax: [phone]

BSI Registered Firm

FM 414

Ind. & Comm. Air Heaters;

Air Moving Equipment;
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Smoke & Heat Ventilators;
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Fans & Systems.