Gunning Heating Products

Electric Trench Heating




Gunning Trench Heating is ideal for offsetting a downdraught from full height glazed perimeter walls, such as Conservatories, or anywhere that wall height is of a premium. The even distribution of heat along the perimeter prevents cold spots,

The casing as standard is 205mm wide x 125mm deep and 1200mm long.


The casing is manufactured from 1.2mm zintec steel sheet and would have a matt black paint finish to the inside face. There would be 8 No levelling bolts fitted through the base of the casing, to allow up to 20mm height adjustment if required.


Where casings are required to form continuous runs, they will also have fixing bolts provided so that several units can be joined together. there are 20mm cable entry holes at each end, this is to allow continuous feed of power supply to run through in the air intake chamber. Provision of an earth continuity link between casings is also allowed for.


The heating element will be fitted within the casing and will have a terminal box at one end, which will be fitted with a cable gland entry for site wiring by others.


Heating elements are of a steel hairpin construction and have steel fins bronze welded to the core, this construction offers excellent heat transfer and an even temperature along the active length. The elements have a 50mm cold zone at the connection end and are fitted into a wiring control box using gland nut and shake proof washers.


Within the casing there is a air splitter/baffle plate, which divides the heating chamber from the air intake chamber, there are two high temperature limit stats fitted to the splitter plates, these are fitted centrally in each half of the casing.

In the event of the casing grille, being partly or completely covered by a carpet, clothing or similar, preventing the air circulation through the casing, thus causing the temperature to rise above the desired maximum.

The heating will be switched off until the internal temperature has fallen by 15 deg C, when the stats will auto reset, there are safety shields fitted over the stats to prevent liquids which may be spilt into the casing coming directly into contact with the wiring terminals.


There is a 22 swg x 6mm wire safety mesh fitted over the entire heating chamber to prevent the ingress of items which may be dropped through the grilles. The mesh is 96% free area, which allows maximum air flow trough the unit whilst not absorbing a great amount of heat, thus keeping the casing temperature to an acceptable level. Above the mesh there is an aluminium grille frame, into which a 60%, or 70%, free area cross bladed flexible grille is fitted. Both grille and frame are finished in anodised satin silver. Please note that the free area of the grille will effect the heat output that can be offered.



With regards to the fitting of an internal control stat, it is possible to do so, but we have our reservations as to whether this is a practical consideration,

with the air inlet temperature, being higher at the point of entry than that in the room, "due to a degree of re-circulation within the case", the calibration of the stat if fitted in the air intake chamber, would have very little relationship between the reading on the stat and that of the room temperature.

We therefore feel that the only practical control of the units should be by a remote room stat.


Similarly the fitting of a double pole rocker switch is not advantageous, even though it would shut the unit off, it would still not be safe to access the power connection box without isolating the unit back at the distribution board.

We would recommend a fused local isolator fitted externally wired back to an RCU Breaker system to be the best application.




Technical Specifications

.          Heating elements are tested to I.E.C 335-1 regulation at the manufacture stage.

.          High limit stats are rated to 100,000 operations and conform to U.L. Approval

            No. E43273, C.A.S. Approval No. LR67165 and 67167 V.D.E. Approval

            No. 13403-4510-1006 T13/11 - NK regulations.

.          Internal wiring is of fibreglass construction to BS 6141 regulations.

.          All wiring terminals conform to E4204, E70188 standards.

.          All factory assembled wiring is carried out by qualified electricians to BS  7671 Part 5.

.          On final assembly each unit is tested to EEC regulations ref. BS 7671 Part 7

            and each unit is individually numbered and test certificate issued.

.          All heating units will be supplied fitted with test ID labels to H.S.E.PM32 and

            heat output ratings to assist with site placements.

.          All units have a 12 month parts warranty from date of supply.



Installation Instructions


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