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How do you supply water to your faucet test bench?

CATEGORY Hydraulic

Reading time : 6 min

@Guillaume Foucher

The water supply for a valve test bench depends directly on the tests to be performed, the type of product being tested, and the resources available on site. A test bench may require cold water, hot water, stable pressure, a specific flow rate, or a closed-loop system to minimize water consumption.

Before selecting a solution, several factors must be determined: the desired pressure, the required flow rate, the number of outlets to be supplied, the required temperature accuracy, and whether there is an existing hot water system or primary loop.

Depending on the available infrastructure, the bench can be powered directly from the mains, from internal tanks, via a hot/cold water loop, or by a standalone generator. These configurations have different advantages and different constraints in terms of control, water consumption, and sizing.

Here are the main options for supplying water to a hydraulic test bench designed for testing plumbing fixtures.

SOMMAIRE

Criteria to consider before choosing a water supply system

Before sizing the power supply for a valve test bench, you must first specify the expected test conditions. A bench used for simple inspection will not require the same setup as one intended for performance, endurance, or qualification testing.

The main criteria to be defined are as follows:

the need for cold water, hot water, or lukewarm water;
the flow rate required to supply one or more test stations;
the expected pressure, which may be constant or variable depending on the test;
the desired temperature accuracy;
the number of benches or modules to be powered;
the choice between a open-loop water supply or closed-loop operation.

These factors make it possible to select a configuration that is suitable for the existing system. In some cases, the site’s existing network is sufficient. In others, tanks, pumps, heat exchangers, or a dedicated hot/cold water generator must be provided.

On-site situation	Possible solution	Key takeaways
Cold water available, no hot water	Heated hot water tank + mains cold water	Simple to integrate, but cold water depends on the main supply network
Both hot and cold water available	Direct supply, with pumps or tanks if required	Practical solution if the network pressure and flow rate are stable
Hot / cold water primary loop available	Heat exchangers integrated into the test bench	High temperature accuracy, without continuous water consumption
No suitable water supply available	Autonomous hot / cold water generator	Complete solution, to be sized according to the number of workstations

Case 1 – You only have cold water

If you don’t have a hot water supply, the easiest solution is to install two tanks: one connected to the hot water supply for the bench (50 L) and one connected to the cold water supply (15 L). We add to that a heating system in the hot water tank and a distributor in the test bench. The distributor will draw a part of the mixed water to the hot water tank, which allows to create a closed hot water circuit (more economical in energy and water).

The other part of the mixed water is drawn towards the drain. In effect, the loop is open to cold water, so the total water consumption is equal to the cold water flow, but there is no need for cooling, because the cold supply is directly at your water supply temperature. This system is the simplest, as there is no cooling system. The disadvantage is that the cold water temperature is not adjustable.

cold water supply<br />
but not hot water

Case 2 – You already have hot and cold water

1: The pressure regulation of your water supply is correct (water supply pressure = test pressure): In this case, the test bench can be supplied directly from your water supply.

2: You need to create pressure variations: you must install pumps at the inlet of the unit on the hot and cold water lines, which will allow you to create pressure variations beyond the mains pressure. In this configuration the water pressure can only be increased.

3: You need to perform tests at a pressure lower than your supply pressure: you must therefore first reduce the pressure using buffer tanks for both hot and cold water, then raise it in a controlled manner using pumps to the test bench.

If you wish to have separate hot and cold water returns, you must install a distributor at the mixed outlet of the bench, to distribute the mixed water on the hot and cold return networks.

Case 3 – You have a primary loop

Your hot and cold water loop is used as an external source of heating and cooling of the bench. Water from the bench’s internal hot water tank is heated by a heat exchanger (with the hot water loop as the heating source). The cold water from the bench’s internal cold water tank is cooled by a heat exchanger (with the cold water loop as cooling source). There is no water consumption through the loop.

The heat exchanger systems allow for very good temperature accuracy (± 0.5°C on hot and cold) and you can easily change the hot and cold temperature setpoints.

Advantages :

You can easily control the temperature and pressure using the internal tanks and pumps.
The test water remains in the tank (it is not connected to your heating and cooling system), which allows for frequent replacement.
Very good regulation of the bench supply temperature and quick change of the hot and cold water temperatures

primary circuit for superheated and chilled water - Plant loop

Case 4 – You do not have a suitable power supply

Solution 1:

The first solution is a small generator which feeds directly the bench. It consists of two tanks (hot water and cold water) and features a heating system for the hot water tank with a capacity of 20 kW and a cooling system for the cold water tank, also with a capacity of 20 kW. The sink is equipped with a hot/cold water distributor so that the mixed water is drawn from the hot water tank and the cold water tank in a closed-loop system, which prevents water waste. There is an energy saving on hot water, but the system needs energy to cool the cold water. There is no heat recovery from cold to hot.

The accuracy of the hot tank is ± 1 °C, while that of the cold tank is only ± 2 °C. This will be sufficient for most endurance tests, but not for some performance testing.

Solution 2:

The bench is powered by a hot and cold water generator that is more powerful than the one in Solution 1. The generator controls the temperature of a hot water tank and a cold water tank. The pump delivers hot and cold water directly to these tanks.

This system is capable of supplying one or more valve test benches, depending on the flow rates required at each station. The system operates in a closed-loop configuration, with integrated hot and cold water production.

The system has a high thermal output: 30 kW for hot water and 30 kW for cold water. Thanks to its large-capacity internal tanks—400 L for hot water and 200 L for cold water—the generator can provide a high instantaneous flow rate while maintaining a precise temperature.

This configuration allows multiple test benches to be supplied with a temperature accuracy of approximately ±0.5 °C for both heating and cooling, within the flow rate limits specified during design. It is therefore particularly well-suited for laboratories that have multiple test benches or conduct regular test campaigns.

The heat pump cools the cold water and recovers some of the energy produced to heat the hot water. The excess heat is then vented through an air heater. This system helps to minimize energy loss compared to more traditional heating and cooling systems.

Both solutions are similar in principle, but Solution 1 is simpler and less expensive. However, it offers lower temperature accuracy, lower heating/cooling capacity, and does not transfer heat from the cooling circuit to the heating circuit. For a more detailed comparison of these configurations, visit our page dedicated to peripheral equipment.

Which configuration should you choose for your test bench?

The right choice depends on the existing system, the required flow rate, the desired temperature accuracy, and the number of stations to be supplied. If the site already has a stable hot/cold water supply, a direct connection may be sufficient. However, if the tests require greater precision or if no suitable supply is available, a standalone generator or a dedicated loop may be preferable.

In any case, the sizing must be specified in the specifications to avoid flow rate limitations, temperature fluctuations, or excessive water consumption during testing.