Vexve TERMOVAR Series Service manual

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TERMOVAR LOADING UNIT
MOUNTING AND OPERATING INSTRUCTIONS
Sizes Rp 25 – Rp 32 – 28 mm With EPP Insulation
With Backflow Preventer Without Backflow Preventer

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GENERALLY
TERMOVAR is an automatic loading unit for sold-fuel boiler/storage tank installations. The loading unit ensures
a minimum return-water temperature into the heating boiler, which encreases the boiler efficency, prevents tarring
and considerably prolongs the lifetime of the heating boiler.
TERMOVAR eliminates the risk of destructive thermal shock caused by surges of cold return water and renders
a more effective burning. The heating boiler reaches the right working temperature quickly. In the end phase of the
firing an automatic balancing valve closes the by-pass loop. This results a maximum cooling of the boiler and the
storage tank is fully filled with hot water.
TERMOVAR automatically allows self-circulation as soon as the fire has gone out so that the rest of the heat in boiler
is transferred into the storage tank. It also allows self-circulation in case of power failure.
MAIN PARTS
1. Thermally operated loading valve
2. Automatic balancing valve
3. Backflow preventer (Model S without)
4. Circulation pump
5. Three thermometers
6. Three ball valves
7. Insulation EPP (optional Order No. 4919)
TECHNICAL DATA
Voltage 230 VAC 50 Hz
Power consumption Pump speed I 45 W, Pump speed II 75 W, Pump speed III 110 W
Max. boiler capacity 80 kW
Max. operating temperature 110°C
Max. operating pressure 1,0 MPa (10 bar)
Thermostatic elements Opening temperatures 45°C, 55°C, 61°C, 72°C or 80°C, fixed
Circulation pump Grundfos UPS 15-60 CIL
Sizes Rp1“, Rp1¼“ or 28 mm compression fittings
Body Cast iron
Dimensions 210 x 210 x 110 mm
Weight 5,0 kg
DIMENSIONING
Pipe dimensioning between heating boiler and storage tank:
TERMOVAR 25 for heating boilers up to 60 kW: DN 25 steel pipe or DN 28 copper pipe
TERMOVAR 28 for heating boilers up to 60 kW: DN 28 copper pipe
TERMOVAR 32 for heating boilers up to 80 kW: DN 32 steel pipe or DN 35 copper pipe

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MOUNTING
The valve unit is mounted upright either on the right or left hand side of the heating boiler. After pipework the
thermometers are pressed onto the front side of the unit.
When starting a new heating installation a very common problem is air in the pipe system. For a trouble free system
the pipework has to be made without air pockets. If this is not possible the system must be fitted with air vents.
The circulation pump should be started at the same time as the firing. The pump also must be stopped soon after the
fire has gone out so that the remaining hot water in the boiler can self-circulate to the storage tank. Several boilers
have factory installed thermostats for pump control. If not, a flue gas thermostat (ACASO Art.-Nr. 7100) must be used.
Self-circulation
For self-circulation the supply pipe should be connected to the top of the storage tank and the return pipe to the
bottom. Self-circulation is obtained as soon as the fire and the circulating pump have stopped. The remaining hot water
will now self-circulate to the storage tank.
Service
TERMOVAR is normally servicefree. The valve unit has three ball valves. All parts can be changed without draining
the system.
FUNCTION
1. Heat up phase
The circulation pump should be controlled by a thermostat
that measures flue-gas temperature. The pump will start
when the boiler is fired up and stop when it has ceased to
fire. The boiler water is circulating to the loading unit and
back while the temperature of the boiler is rising.

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2. Loading phase
The thermostic element in the loading unit is affected by the
temperature of the water flowing from the boiler to the
loading unit. The element starts to open and allows
return water from the storage tank to be mixed with supply water
before it returns back to the boiler. The temperature of the mixed
water determines the working position of the thermostatic element.
An automatic balancing valve in the loading unit regulates the
internal flow of the supply water from the boiler.
When the temperature rises the element starts to close the
balancing valve. This causes a higher flow of return water into
the boiler. When the thermostatic element is fully open the balan-
cing valve is closed and the entire capacity of the pump is used
for cooling the boiler and loading the storage tank.
3. End phase
The thermostat element is fully open. The balancing valve
is closed. This results a maximum cooling of the heating
boiler and the storage tank is fully filled with supply water.
4. Self-circulation
Self-circulation is obtained as soon as the fire and the
circulating pump have stopped. The remaining hot water
will self-circulate to the storage tank.
When the storage tank is warmer than the boiler a backflow
preventer stops the self-circulation from tank to boiler.
In case of power or pump failure the backflow preventer
will open automatically for self-circulation.
Model S is delivered without backflow preventer.

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CIRCULATING PUMP
TERMOVAR loading unit has a Grundfos UPS 15-60 CIL circulating pump. Flow and capacity
according to the diagram below. Pump speed III is recommended. In a normal installation with
pump speed III the flow will be 40 – 46 l/m.
THERMOSTATIC ELEMENTS
Every thermostatic element has a code on the copper body.
Code on element Opening temperature Fully open
9311 45°C 60°C
8749 55°C 67°C
8743 61°C 73°C
8719 72°C 84°C
1456 80°C 92°C
REPLACING THE THERMOSTATIC ELEMENT
- Turn off the pump
- Close the three ball valves
- Open the cover No. 22 opposite the pump
- Take out the element housing and the spring
After replacing the element open the three ball valves and start the pump.
IMPORTANT! Check that there is no air in the system.

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11 13 14 16
15 24
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35
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2518 19 21 22
23 6 78910
SPARE PARTS
Part No. Art.No Part Part No. Art.No Part
1 4899 Grundfos pump UPS 15 – 60 CIL 6, 16, 21 4919 O-ring EPDM Ø 36,2mm x 3mm
2, 12 ,14 4902 Thermometer 51 x 7 mm 7, 15, 22 4908 Cover G 1¼”
3 4945 TERMOVAR body 45ºC 8, 9, 20 4885 Element housing with spring
3 4955 TERMOVAR body 55ºC 10 4911 Element code 9311 45ºC
3 4961 TERMOVAR body 61ºC 10 4912 Element code 8749 55ºC
3 4972 TERMOVAR body 72ºC 10 4913 Element code 8743 61ºC
3 4980 TERMOVAR body 80ºC 10 4914 Element code 8719 72ºC
4, 13, 18 4918 Sealing 44 x 32 x 2 mm 10 4915 Element code 1456 80ºC
5, 11, 19 4904 Ball valve Rp 1½” x 28 mm 17 4916 Backflow preventer (Model S without)
5, 11, 19 4905 Ball valve Rp 1½” x 1” 23 -- Balancing valve (included in part 3)
5, 11, 19 4906 Ball valve Rp 1½” x 1¼” 24, 25 -- Sealing Ø 40mm x 5mm
(for part 4916)

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40
0
20
120
100
60 80 60
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40
100
120
80
120
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40
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60 80
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Heating boiler Right-hand mounting Storage tank
40
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20
120
100
60 80
60
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20
40
100
120
80
120
0
40
20
60 80
100
Storage tank Left-hand mounting Heating boiler