ESBE VTC511 cast iron load valve with internal thread
Front drawing with dimensions of the ESBE VTC500 load valve
Side drawing of the ESBE VTC500 load valve

ESBE VTC500 thermostatic load valve for biomass boilers up to 150 kW

Modelo
Regular price€239,58
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  • 4 in stock
  • Backordered, shipping soon

At Q-TECH, we apply the same clear rules for everyone: the law protects you, and when applied correctly, it protects us as well. By processing your purchase, you accept our General Terms and Conditions of Sale. If you are purchasing as a consumer (B2C), nothing stated herein limits the rights granted to you by mandatory law (RDL 1/2007, TRLGDCU): the 3-year legal warranty of conformity and the right of withdrawal under the terms and with the exceptions legally provided, which are detailed below. References to "B2B" apply only to businesses and professionals.

Your guarantees

  • Rights intact: 14 days of withdrawal from receipt for most products—subject to the legal exceptions you will see below, such as goods made to your specifications—and a 3-year legal warranty of conformity, under the terms of the TRLGDCU.
  • Conformity with the description: we guarantee that the equipment will correspond to the published technical description and what one could reasonably expect from it (arts. 115 et seq. TRLGDCU). Images and videos are for guidance only: the manufacturer may supply a more recent revision of the product or introduce minor aesthetic, packaging, or firmware changes, without this constituting a lack of conformity as long as the described characteristics and performance are maintained.
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Responsible use and your part

  • If you are thinking of returning it, keep it as you received it: without installing or activating it, with its seals, accessories, and packaging intact. This is how to ensure a full refund, without deductions.
  • Handling that exceeds inspection reduces value: handling the equipment beyond what is necessary to verify its nature and operation may result in a real, assessed, and case-by-case justified deduction (art. 108.2 TRLGDCU), never a fixed percentage. In particular: activating or registering the serial number, linking it to a manufacturer's account or app, circulating water through hydraulic equipment, unsealing probes, or installing software or consumables. Initial inspection of the product does not lead to a deduction.
  • The same item must be returned: withdrawal requires returning the supplied unit. Different equipment, or equipment with prior use, age, or wear prior to purchase, does not constitute a valid withdrawal.
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  • Delivery of bulky goods: delivery is made to the curb. B2C: transport risk is ours until physical delivery (art. 66 ter); we recommend noting visible damages on the delivery note and notifying us of breakages within 24-48 hours with photographs to activate the insurance. B2B: inspection and notation on the delivery note are mandatory; hidden damages must be reported within 24 hours (art. 366 CCom). Unjustified rejection or incorrect shipping information will entail the actual outbound and return costs (approx. €85-550 for heavy machinery).

Made to your measure (Advanced Pre-Assembly)

  • If your order includes equipment, racks, hydraulic assemblies, or technical rooms made or configured according to your specifications (permanent joints, custom cuts or wiring, parameterization, pressure testing), these are custom goods without the right of withdrawal from the conclusion of the contract (art. 103.c TRLGDCU; CJEU Case C-529/19), which is informed before purchasing and documented in the signed Order Note. A test you request without permanent modification retains your right of withdrawal, with only the actual loss of value caused by that test being deducted. Would you prefer to receive it tested, configured, and ready to connect, without assuming these risks? Contract our Advanced Pre-Assembly or the prior technical audit.

If you are purchasing as a business or professional (B2B)

  • The transaction is governed by the Commercial Code: firm sale, without the right of withdrawal; notification of defects within 4 days (apparent) / 30 days (hidden), arts. 336 and 342. Q-TECH acts as a distributor and excludes indirect damages, loss of profit, and data loss, limited to the price of the equipment, without prejudice to the manufacturer's commercial warranty.

Product warnings v1.0 · June 2026. Information summary; the complete and binding conditions are those published at q-tech.es.

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ESBE VTC500 thermostatic load valve for biomass boilers up to 150 kW

The ESBE VTC500 keeps the return to the solid fuel boiler hot while it loads the accumulation tank, with no electricity and no adjustment. At Q-Tech we integrate it in the pre-assembled plant room, tested in our workshop before it reaches your site.

Summary

Type3-way thermostatic load valve
Brand and modelESBE VTC500 series (VTC511)
UseReturn protection of solid fuel boilers and loading of accumulation tanks, according to ESBE
Boiler outputUp to 150 kW
Opening temperature50, 55 or 60 °C depending on the model
ConnectionInternal thread Rp 1 (DN 25) or Rp 1¼ (DN 32)
Power supplyNone: an internal thermostat controls the mixing
Q-Tech installationIntegrated and tested in the Q-Tech pre-assembled plant room

What is the ESBE VTC500?

The ESBE VTC500 is a cast iron 3-way thermic valve that protects boilers up to 150 kW from return temperatures that are too low, according to ESBE. It is installed in the return pipe to the boiler and works in any mounting position.

What problem does it solve?

When water returns cold to a solid fuel boiler, combustion does not reach its temperature and tar and condensation build up. ESBE states that a high return temperature, guaranteed over the whole combustion cycle, gives higher efficiency, less tarring and a longer boiler life.

The VTC500 has a thermostat that opens port A when its opening temperature is reached. It regulates on two ports, so it works with no adjustment valve in the bypass, according to ESBE.

Technical data

Pressure classPN10
Maximum differential pressure100 kPa (1 bar); between A and B, 30 kPa (0.3 bar)
Media temperatureFrom 0 to 110 °C
LeakageA to AB, maximum 1% of Kvs; B to AB, maximum 3% of Kvs
Rangeability Kv to Kv minimum100
MediaHeating water to VDI 2035, water with up to 50% glycol and water with up to 28% ethanol
ConnectionsInternal thread Rp (EN 10226-1)
Body and cover materialNodular cast iron EN-JS 1050
ConformityPressure Equipment Directive (PED), article 4.3; no CE marking

Models and data by variant

ModelConnectionOpening temperatureKvs (m³ per hour)Dimensions A, B, C and DNet weightReference
VTC511 DN 25Rp 1 internal50 °C ±5 °C993, 34, 69 and 47 mm0.84 kg51020100
VTC511 DN 25Rp 1 internal55 °C ±5 °C993, 34, 69 and 47 mm0.84 kg51020200
VTC511 DN 25Rp 1 internal60 °C ±5 °C993, 34, 69 and 47 mm0.84 kg51020300
VTC511 DN 32Rp 1¼ internal50 °C ±4 °C14105, 38, 75 and 55 mm1.4 kg51020600
VTC511 DN 32Rp 1¼ internal55 °C ±4 °C14105, 38, 75 and 55 mm1.4 kg51020700
VTC511 DN 32Rp 1¼ internal60 °C ±4 °C14105, 38, 75 and 55 mm1.4 kg51020800

Compatibility and limits

  • For boilers up to 150 kW, according to ESBE.
  • Maximum differential pressure of 1 bar, and 0.3 bar between ports A and B.
  • Glycol reduces the maximum valve output; ESBE asks for this to be considered when sizing it.
  • The circulation pump is not included.
  • The opening temperature is fixed; it is changed by replacing the thermostat with an ESBE VTC951 thermostat of another temperature.
  • ESBE recommends fitting shut-off valves on the connections to make maintenance easier.
  • No CE marking: it is pressure equipment under article 4.3 of the PED.

When this product is not the right choice

ProductWhen to choose itMaximum boiler outputPump included
ESBE VTC300 load valveIf your boiler does not exceed 30 kW and you want a compact brass valve30 kWNo
ESBE LTC300 load unitIf you want the valve and a high-efficiency pump in one unit50 to 90 kW depending on the opening temperatureYes, 6 m

Frequently asked questions

Which model do I need?

It depends on the boiler output, the flow and the return temperature your boiler manufacturer requires. The DN 25 has Kvs 9 and the DN 32 Kvs 14; send us your boiler data and we will tell you which valve to choose.

Can the opening temperature be changed?

Yes, by replacing the thermostat with an ESBE VTC951 of another temperature, according to ESBE.

Does it include the pump?

No. If you prefer the valve and the pump in one unit, the ESBE LTC300 load unit integrates both.

Does it need maintenance?

Not under normal conditions, according to ESBE.

Can I install it myself?

It is not recommended: it should be installed by a professional, following ESBE's instructions. Q-Tech delivers it fitted in the plant room or installs it with an Expert Technician.

What is the delivery time?

We have it in stock in Málaga and dispatch it as soon as we confirm your order.

Q-Tech installation and support

Q-Tech fits the VTC500 in the pre-assembled plant room: assembled and tested in our workshop, it arrives ready to connect to the boiler and the tank. You can book workshop pre-assembly, an on-site hourly Expert Technician or a technical call to choose the model. See also our biomass collection or message us on WhatsApp.

Documentation

Availability and lead times: this item is in stock at our warehouse. Occasionally, depending on the time of year, the stock update may contain an error. If no units are available when you place your order, we will order it urgently and inform you immediately of the updated delivery time.

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