Vent-Axia Lo-Carbon Tempra 100mm (4") Heat Recovery Fan Longer Cell, Humidistat, Timer and Pullcord - 403836

Product Overview

The Tempra LHTP 403836 is a through-the-wall heat recovery ventilation unit designed to retrofit into existing 100 mm (4″) wall penetrations while providing advanced control features. It is the “longer cell” version—intended for wall thicknesses up to about 460 mm—making it suitable for thicker walls. The unit carries an IPX4 rating, making it suitable for installation in bathrooms, kitchens, or other moisture-prone spaces.

In terms of performance, the 403836 model provides both continuous trickle ventilation and a boost mode. The trickle settings are typically 6 l/s and 9 l/s, while the boost mode reaches up to 15 l/s when higher extraction is required (e.g. during showering). Its heat recovery system is capable of recovering up to around 78% of the thermal energy from the outgoing stale air, transferring that heat into the incoming fresh air to reduce heat loss and improve energy efficiency.

The “HTP” in LHTP reflects that the unit combines multiple control mechanisms: it integrates a humidistat, overrun timer, and pull-cord override. The humidistat allows the fan to boost automatically when humidity exceeds a preset level; the timer ensures continued extraction after activation for a controlled period; and the pullcord offers manual override where needed. Additional features include a “summer mode” (extract-only) setting to prevent overheating in warm months, low power consumption (as low as ~3.2 W on trickle), and quiet operation (≈ 20 dB(A) in trickle).

Downloads

Download 403836 Product Manual

Specification