Vaillant 75 mm plug for low-profile manifold, 10 pcs - recoVAIR /4

Product detailed description

Vaillant 75 mm cap for low-profile manifold, 10 pcs - recoVAIR /4

The 75 mm cap is a small but functionally important accessory part of the Vaillant recoVAIR /4 system, used to seal unused outlets of the low-profile air manifold (available in 12-outlet and 17-outlet versions). The product is supplied in a pack of 10 pieces, which corresponds to the typical need during installation or subsequent modification of the distribution system, when not all manifold outlets are used at once.

In practice, an air handling project rarely uses exactly all available manifold outlets - either a manifold with a larger capacity is chosen to allow for possible future layout changes, or several rooms are ventilated by a shared branch. In both cases, it is essential to reliably seal the remaining, unused outlets to prevent unwanted air leakage (so-called short-circuit flow) outside the branches that are actually in use, which would otherwise reduce pressure and flow in the active branches and degrade the function of the entire balanced ventilation system.

This small part is a typical example of the fact that, in controlled ventilation systems with heat recovery, the resulting quality and efficiency depends not only on the central unit itself, but also on how thoroughly every detail of the distribution system is finished, down to the smallest components. The investment of a few euros in a pack of caps is negligible compared to the cost of subsequently searching for the cause of unbalanced ventilation after the entire distribution system has been completed and covered by ceilings.

Technical characteristics

• Purpose: sealing unused outlets of the low-profile manifold (75 mm)
• Pack: 10 caps in one sealed pack
• Cap diameter: 75 mm (matches exactly the outlet diameter of the low-profile manifold of the recoVAIR /4 system)
• Material: rigid plastic with a sealing element for reliable outlet sealing, resistant to common temperatures and humidity in the ceiling void
• Simple installation without tools - fits directly onto the manifold outlet by hand, no gluing or sealing compound required
• Compatibility: 12-outlet and 17-outlet low-profile manifold, recoVAIR /4 system, universal for all central units in this range
• Compatibility with units: recoVAIR VAR 150/4 L, VAR 150/4 R, VAR 260/4, VAR 260/4 E, VAR 360/4, VAR 360/4 E
• Country of origin: Germany (Vaillant Group manufacturing plant)
• Warranty: 2 years from sale to the end customer

When you need these caps

• During initial installation of the distribution system, when the project requires only part of the manifold outlets to be used (e.g. a 17-outlet manifold in a house with fewer ventilated rooms, with reserve capacity for a possible future extension or layout change).
• During subsequent renovation or a change in room layout, when a distribution branch is removed and the corresponding manifold outlet needs to be sealed.
• As a replacement for a damaged or lost cap during service work on an existing distribution system.

Installation procedure

1. Identify the outlets on the manifold that will not be used in the project (i.e. no flexible hose will be routed from them to any terminal element).
2. Fit the 75 mm cap onto each such outlet with even pressure until it clicks or settles into its final position according to the outlet design.
3. Visually and manually check that the cap sits evenly around the entire circumference of the outlet without gaps.
4. Before covering with a ceiling, we recommend checking the tightness of the entire manifold, including all fitted caps (e.g. by a simple test run of the unit's fan at lower output while checking for audible air leaks).

Why it is important to seal unused outlets

The low-profile manifold works on the principle of splitting a single incoming air stream (from the main EPP duct route) into several outgoing branches. If any of the outlets remains open without a connected hose and without a cap, the air will "find the path of least resistance" through that open outlet instead of flowing evenly into all connected branches leading to the rooms. The consequences are:

• reduced airflow in the branches actually in use, meaning less fresh air is supplied to the rooms than the project envisages,
• uneven ventilation of individual rooms compared to the designed state,
• in the case of an open outlet in the ceiling void, possible air leakage directly into the ceiling void instead of into the occupied rooms, reducing the actual efficiency of the entire system.

That is why the manufacturer recommends always having 75 mm caps on hand for any installation or modification of a distribution system with a low-profile manifold, even in a greater quantity than currently needed - future layout changes very often require sealing another outlet without having to order individual pieces additionally.

Compatibility with the recoVAIR /4 system

The 75 mm caps are designed precisely for the outlets of Vaillant recoVAIR /4 low-profile manifolds (both 12-outlet and 17-outlet variants) and are part of a complete range of accessories for this system, together with the spigot, spigot cap, 75/62 mm flexible hoses and straight adapters of the same diameter. Do not combine these caps with manifolds from other manufacturers or of different outlet diameters - they may not seal correctly.

Relation to air performance and energy efficiency of the system

Although at first glance this seems like an insignificant small part, listed among the cheapest items in the entire recoVAIR /4 price list, its absence or incorrect use has a direct impact on the energy balance of the whole house and on the occupants' satisfaction with ventilation quality in individual rooms. The recoVAIR /4 central units are designed to deliver a precisely defined amount of air to individual rooms according to the project, at a given fan output. If part of the fan's capacity is "wasted" on unproductive flow through an unsealed, unused manifold outlet, the system must either run at higher speed (and therefore with higher electricity consumption and noise) to achieve the required airflow in occupied rooms, or, in a worse case, the actual airflow in the rooms falls short of the designed value, and occupants perceive this as insufficient ventilation, odour or increased humidity. The investment of a few cents per cap therefore clearly pays off in the long run compared to the losses caused by a leaky distribution system.

Checking tightness after fitting the caps

After fitting all the necessary caps onto unused manifold outlets, we recommend performing a simple functional test before covering the distribution system with a ceiling:

1. Run the central unit at test or maximum output.
2. Hold your hand or a thin strip of paper/foil close to each fitted cap in turn - a correctly sealed outlet should show no perceptible air movement or audible whistling.
3. Check the whole manifold acoustically - a noticeable hissing or whistling sound around any of the caps indicates incorrect fitting, which needs to be corrected before covering with the ceiling.
4. We recommend recording the result of the check in the installation report together with other checks of the distribution system's tightness.

Typical practical situations where a larger number of caps comes in handy

Installation companies ordering accessories for recoVAIR /4 manifolds often recommend having a slightly higher number of caps on hand than currently needed, for the following practical reasons:

• During construction, the investor may decide to change the layout or number of ventilation points in individual rooms, which requires additional reconfiguration of the manifold connections.
• During a future extension or change of room purpose (e.g. converting an attic space into a habitable loft), it may be desirable to subsequently open up an outlet or, conversely, seal one.
• During any future replacement or servicing of individual hose branches, a cap is temporarily used to seal the outlet until a new hose is fitted, so that the rest of the system is not taken out of operation during the work.

Maintenance and care

The caps require no maintenance during system operation, as they contain no moving, electronic or filtering components, and their sole function is a permanent, reliable sealing of the outlet. We recommend:

• checking that the caps remain firmly and tightly fitted whenever work is carried out on the ceiling around the manifold,
• keeping spare caps on hand for any change in room layout or future expansion of the distribution system, in case newly freed outlets need to be sealed again,
• replacing a cap as soon as possible with a new one in the event of mechanical damage (e.g. cracking due to careless handling), in order to maintain the tightness of the entire manifold.

Difference between the outlet cap and the spigot cap

The accessory range for low-profile manifolds of the recoVAIR /4 system includes two different types of caps, which are sometimes confused despite having a completely different function and size:

• 75 mm manifold outlet cap (this product) - used to seal any of the 12 or 17 manifold outlets that would otherwise lead via a flexible hose to a specific room. Supplied in packs of 10 pieces, since not all outlets are typically used at once.
• Low-profile manifold spigot cap (a separate product) - has a different diameter and is used to seal the main connection of the manifold to the round EPP duct, for example during transport, storage or a temporary shutdown of the manifold before connection to the main route.

When ordering accessories, it is therefore important to distinguish between these two products and to order exactly the type of cap that matches the location where it is to be used - the 75 mm outlet, or the manifold's main spigot with a different connection size.

Recommended order quantity

When planning your purchase, we recommend basing it on the air handling project documentation, which precisely defines how many manifold outlets will actually be used in the given project and how many will remain free. As a rule of thumb, you can use the following approach:

• If the project uses a 12-outlet manifold and only, for example, 9 branches are actually used, 3 outlets remain to be sealed - one pack of 10 pcs with a reserve fully covers this need.
• For a 17-outlet manifold with a larger difference between capacity and actually used branches, it may be necessary to order two packs to leave a reasonable reserve for possible future modifications.
• Installation companies working on multiple properties usually keep several packs of caps in stock as a standard consumable for this type of manifold.

Given the low price of this accessory compared to the overall cost of implementing the air handling distribution system, if in doubt, we recommend ordering one more pack of caps rather than having to order individual pieces later, when the manifold may already be covered by a ceiling and access to it more complicated.

Why choose a genuine Vaillant part

Even such a small part as an outlet cap has a direct impact on the actual performance and balance of the entire controlled ventilation system with heat recovery. A genuine cap from the manufacturer guarantees precise dimensional and shape matching to the outlet of a specific recoVAIR /4 manifold, which may not be guaranteed with non-original or universal replacements and can lead to leaks that are difficult to detect once the distribution system has been covered by a ceiling.

Frequently Asked Questions