KORAFLEX Optimal FKO

most available dimensions

KORAFLEX Optimal FKO represents the widest range of trench heater models. The black lacquered galvanized steel casing comes with optional decorative U-, F- or Cross frames, and a wide choice of grilles.

ECONOMIC version – basic version, black lacquered galvanized steel casing, non-lacquered heat exchanger
EXCLUSIVE version – black lacquered galvanized steel casing, RAL 9005 black lacquered heat exchanger

Technical data Demand

Heating
Natural convection
Higher performance
Low energy consumption

ECONOMIC version	basic version, black lacquered galvanized steel casing, non-lacquered heat exchanger
EXCLUSIVE version	black lacquered galvanized steel casing, RAL 9005 black lacquered heat exchanger
Depth [mm]	70, 90, 110, 130, 150, 190, 300, 450 mm
Width [mm]	140, 200, 260, 320, 400 mm
Length [mm]	800 to 3 000 mm (by 100mm)
Heat output [W]	from 41 to 3 480 W
Max. operating pressure [MPa]	1.2 MPa
Max. operating temperature [°C]	90 °C
Connecting thread	inner G ½"
Cover grilles
	Where a left-hand connection to the heating system is required, rotate the heat exchanger in the trench heater by 180°. Cross grille – design solutions – the casing must undergo alternation. Cross grilles must be ordered together with trench heaters. These trench heaters will be fitted with a Cross frame suitable for a Cross grille.

THeat output [W] where t1/t2/ti / EN 16430. Measurements shown in mm including U-frame.

Inlet temperature in °C

Outlet temperature in °C

Air temperature in °C

ΔT

ΔT = 50 °C		Length [mm]																							Temperature exponent
Depth [mm]	Width [mm]	800	900	1000	1100	1200	1300	1400	1500	1600	1700	1800	1900	2000	2100	2200	2300	2400	2500	2600	2700	2800	2900	3000	Temperature exponent
70	140	42	51	61	71	81	91	101	111	121	130	140	150	160	170	180	190	200	210	219	229	239	249	259	1,4629
70	200	76	90	105	120	135	150	165	179	194	209	224	239	254	268	283	298	313	328	342	357	372	387	402	1,4587
70	260	90	108	126	143	161	179	196	214	232	250	267	285	303	320	338	356	373	391	409	426	444	462	480	1,6148
70	320	102	124	146	168	189	211	233	255	276	298	320	342	364	385	407	429	451	472	494	516	538	559	581	1,5550
70	400	131	157	183	208	234	260	286	311	337	363	389	414	440	466	492	517	543	569	595	620	646	672	698	1,5235
90	140	50	62	74	86	98	110	122	134	146	158	170	182	194	206	218	230	242	254	266	278	290	302	314	1,5247
90	200	120	143	167	191	214	238	261	285	308	332	355	379	402	426	449	473	496	520	543	567	590	614	637	1,5373
90	260	153	183	213	243	273	303	333	363	393	423	453	483	513	543	573	603	633	663	693	723	753	783	813	1,5643
90	320	195	236	278	319	361	402	444	485	526	568	609	651	692	733	775	816	858	899	940	982	1023	1065	1106	1,4599
90	400	275	329	383	437	490	544	598	652	706	760	814	868	922	976	1029	1083	1137	1191	1245	1299	1353	1407	1461	1,4607
110	140	55	69	82	95	108	122	135	148	161	174	188	201	214	227	240	254	267	280	293	307	320	333	346	1,4888
110	200	142	170	198	226	254	282	309	337	365	393	421	449	477	505	532	560	588	616	644	672	700	728	755	1,4739
110	260	184	220	257	293	329	365	401	437	473	510	546	582	618	654	690	726	763	799	835	871	907	943	979	1,4385
110	320	237	287	338	388	438	489	539	589	640	690	740	791	841	891	942	992	1042	1093	1143	1193	1244	1294	1344	1,4622
110	400	327	391	455	520	584	648	712	776	840	905	969	1033	1097	1161	1225	1289	1354	1418	1482	1546	1610	1674	1739	1,4569
130	140	79	95	110	126	141	157	172	188	203	219	234	250	265	281	296	312	327	343	358	374	389	405	420	1,5855
130	200	144	172	200	228	256	284	313	341	369	397	425	453	481	510	538	566	594	622	650	679	707	735	763	1,5143
130	260	203	243	283	323	363	403	443	482	522	562	602	642	682	722	761	801	841	881	921	961	1001	1041	1080	1,6077
130	320	284	340	395	451	506	562	618	673	729	785	840	896	952	1007	1063	1119	1174	1230	1286	1341	1397	1453	1508	1,5011
130	400	364	435	506	578	649	720	791	863	934	1005	1077	1148	1219	1291	1362	1433	1505	1576	1647	1718	1790	1861	1932	1,5119
150	140	92	109	127	145	163	181	199	217	235	253	271	289	307	325	343	361	379	397	414	432	450	468	486	1,5470
150	200	154	185	215	245	276	306	336	366	397	427	457	488	518	548	578	609	639	669	700	730	760	790	821	1,5528
150	260	238	284	331	378	424	471	517	564	611	657	704	751	797	844	890	937	984	1030	1077	1124	1170	1217	1263	1,5240
150	320	314	376	438	499	561	623	684	746	808	869	931	992	1054	1116	1177	1239	1301	1362	1424	1486	1547	1609	1671	1,5165
150	400	389	465	541	617	693	770	846	922	998	1074	1151	1227	1303	1379	1455	1531	1608	1684	1760	1836	1912	1989	2065	1,5296
190	200	172	205	239	273	306	340	374	407	441	475	508	542	576	610	643	677	711	744	778	812	845	879	913	1,5264
190	260	260	311	362	413	464	515	566	617	668	719	770	821	872	923	974	1025	1076	1127	1178	1229	1280	1331	1382	1,4983
190	320	384	459	534	609	685	760	835	910	986	1061	1136	1211	1287	1362	1437	1512	1588	1663	1738	1813	1888	1964	2039	1,5283
190	400	526	629	732	835	938	1041	1144	1248	1351	1454	1557	1660	1763	1866	1969	2072	2175	2278	2382	2485	2588	2691	2794	1,5329
300	260	308	368	428	489	549	610	670	730	791	851	911	972	1032	1092	1153	1213	1273	1334	1394	1454	1515	1575	1635	1,4820
300	320	457	546	636	725	815	904	994	1083	1173	1262	1352	1441	1531	1620	1710	1799	1889	1978	2068	2157	2247	2336	2426	1,4769
300	400	559	669	778	888	998	1107	1217	1327	1436	1546	1656	1765	1875	1985	2094	2204	2313	2423	2533	2642	2752	2862	2971	1,4734
450	260	426	510	593	677	761	844	928	1011	1095	1178	1262	1346	1429	1513	1596	1680	1764	1847	1931	2014	2098	2181	2265	1,4575
450	320	506	605	704	803	902	1001	1100	1200	1299	1398	1497	1596	1695	1794	1893	1993	2092	2191	2290	2389	2488	2587	2687	1,4849
450	400	655	783	912	1040	1168	1297	1425	1554	1682	1810	1939	2067	2196	2324	2452	2581	2709	2837	2966	3094	3223	3351	3479	1,4713

Standard contents

RAL 9005 black lacquered galvanized steel casing
Economic – non-lacquered Al/Cu heat exchanger with bleed valve
Exclusive – RAL 9005 black lacquered Al/Cu heat exchanger with bleed valve
aluminium U-frame silver elox
metal cover plate
levelling set screws and 4 anchors
spacers for correct installation and concreting
hardboard cover to protect trench heater from contamination
durable packaging, installation instructions

Optional accessories

choice of grilles
Cross grille – design solutions – necessary to order together with trench heater
light/dark bronze and black elox or RAL colour chart lacquered aluminium U-frame
silver, light/dark bronze and black elox or RAL colour chart lacquered aluminium F-frame
thermostatic head with incorporated control and immersion remote sensor
24V DC power supply
24V DC or 230V AC room thermostat for regulation
24V DC or 230V AC thermoelectric actuator
raised floor structural supports
lockshield, thermostatic valve
½" × ½" 90° brass elbow for connection facilitation
flexible stainless steel hose
strengthened OSB cover for installation purposes

TRENCH HEATER COMPONENTS

1black laquered galvanized steel casing

2choice of grille (please order separately)

3choice of aluminium frame

4Al/Cu heat exchanger

54 anchors

6levelling set screws

7metal cover plate

8brackets

9spacers for correct installation and concreting

Suitable grilles

Roll-up aluminium silver	Linear aluminium silver	Roll-up aluminium dark bronze	Linear aluminium dark bronz
Roll-up aluminium light bronze	Linear aluminium light bronze	Roll-up aluminium black elox - NEWS	Linear aluminium black elox - NEWS
Roll-up steel	Linear steel	Roll-up stainless steel	Linear stainless steel
Roll-up natural / lacquer beech	Roll-up natural / lacquer oak	Roll-up natural / lacquer mahogany (upon request)	Cross (upon request)

Frames

U-frame	F-frame	Cross frame - Lowered casing edge

Decorative U-shaped and F-shaped frames are available as standard in aluminium with silver, black, dark bronze or light bronze elox finishes. U-frame and Cross frames are available also in black elox. Frames may also be lacquered (powder coated) using colours from the RAL colour chart. Frames are in every case supplied as a component of trench heaters, and the type required must be specified when ordering in the Order Code.

FK TRENCH HEATER INSTALLATION

Construction recommendations

To ensure correct operation, it is essential that the following principles are respected.

Trench heaters must be installed horizontally with the heat exchanger on the window side. For the grille to function correctly, the upper edge of the casing must be straight and level (not buckled or bent).
The maximum recommended distance of the trench heater from the wall/window is 100 mm.
The size of the trough in the floor for the trench heater installation should be at least 100 mm bigger (both in length and width) than the convector.
We recommend connecting the trench heater to the heating system using a lockshield and thermostatic valve. The heat exchanger connection is by an inner G½ thread. Following connection to the heating system, bleed and carry out a pressure test.
When concreting, the trench heater must be levelled using the set screws provided and fastened to the floor using the anchors provided. The anchors keep the trench heater in place while pouring concrete.
Using anchors will extend the bottom width of the trench heater by 42 mm from each side.
While pouring concrete, the trench heater may be weighed down.
While pouring concrete it is particularly important to brace the trench heater to prevent longitudinal buckling. Trench heaters are fitted with spacers for this purpose. (Please note: FKP models as standard are, however, not equipped with spacers.) Following concreting, these spacers are easily removed.
While pouring concrete or anhydrite it is essential to seal all connection openings to prevent leakage.
Where the trench heater is not concreted in, floor supports are recommended to be used to incorporate the trench heater into a raised floor. Standard trench heater models are not self-supporting.
We recommend insulating the outer side of the trench heater casing along the length of the heat exchanger with polystyrene to prevent heat loss into the floor.
To avoid contaminating the trench heater, we recommend maintaining the protective hardboard cover in place during construction work. The board, which is included in the standard contents, is not suitable for walking on and serves solely to protect the trench heater from contamination during installation. Strengthened OSB covers for installation purposes are available as option extras.
Trench heaters fitted with stainless steel casings installed in humid environments – marked KORALEX Pool FKP – are equipped as standard with overflow drains. During installation, the pipe at the bottom of the trench heater must be connected to piping with sufficient gradient to drain overflow water. We recommend installing a U-bend to prevent odour.

Recommended positioning of heat exchangers in trench heaters

•

Trench heaters should be positioned a maximum of 100 mm from windows. In order to achieve maximum performance, the recommended position for heat exchangers in the trench heater is always on the window side. This results in natural air flow, whereby warm air rises and cool air is drawn into the trench heater. In this way, cool air at the window is screened and the air in the room is heated.

TRENCH HEATER INSTALLATION

1 - trench heater with natural convection, 2 - heat exchanger, 3 - grille, 4 - U-frame, 5 - F-frame, 6 - set screws, 7 - anchors, 8 - up to 300mm deep dividing partition, 9 - window, 10 - floor level, 11 - grout,
12 - expansion joint, 13 - insulation, 14 - concrete filler, 15 - sub-floor

Raised floor installations

• Structural supports for raised floor trench heater installations offer stable and effective solutions. Structural supports are manufactured from non-lacquered steel and are suitable for raised floors of a depth of up to 500 mm. Structural supports are suitable for Optimal FKO and Basic FKB models.

Supports must be ordered together with trench heaters due to structural alterations to convector casings! Components of several types of raised floor support are integral parts of the trench heater body.

Raised floor installations KORAFLEX FK

Trench heater multiple installations

Casing types according to water connections and lowered sides for multiple installations

• Lowered trench heater casing sides are used where invisible connections are desired between trench heaters (multiple trench heaters around a room, eg. in administrative buildings, restaurants, hotels, etc.). When ordering grilles, care must be taken to include information in the order code that the grilles required are to be used with trench heaters with lowered faces.

ORDERING CODES

Example of ordering code: FKO-100/11/26-V1U1P0

KORAFLEX trench heater with natural convection, Optimal model, length 100 cm, depth 11cm, width 26 cm, counter-flow non-lacquered heat exchanger, U-frame silver elox, right-hand connection to heating system, without lowered face.

KORAFLEX	Convection	Optimal		Length/Depth/Width (cm)		Heat exchanger type	Heat exchanger colour	Frame	Frame colour	Connection side	Lowered face
F	K	O	-	100/11/26	-	V	1	U	1	P	0
						V counter-flow P* single-stream 0 without heat exchanger	1 non-lacquered 5 RAL 9005 9 other colour RAL 0 without heat exchanger	U -frame F -frame C for Cross grille 0 without frame	1 silver elox 2 dark bronze elox 3 light bronze elox 5 black elox 9 other RAL colour 0 without frame	P right	0 without lowered face 1 lower face – input side 2 lower face – opposite input side 3 both sides lower

P* – single-stream heat exchangers are fitted as standard in trench heaters 140 mm wide, depth of 70, 90 and 110 mm only.

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