Specialist Crop Storage Engineering

Tel: +44 (0) 1476 591592 Email: info@farmelec.co.uk

Made in the UK

Evaporative Humidifier Free Standing

Evaporative Humidifier Free Standing
To help maintain high levels of relative humidity within crop storage buildings, Farm Electronics
has developed a unique floor standing evaporative humidifier which halts damaging weight and
quality loss in potatoes and other root crops during storage.

Farm Electronics have utilised the HUMIDRAFT humidifier coil and installed it in a floor standing 
module. Locating the assembly at floor level, makes installation of electrical and water supplies and 
drainage much simpler and safer. Several modules can be stood side by side to provide sufficient
surface area for the air volume to be humidified.

The standard module occupies approximately 0.34m2 (3.2sq.ft) 
of floor space. With an airflow of some 1.7m3/s (3600 cub.ft per 
min) it is capable of maintaining the relative humidity levels at 
between 95%-98%. This enables the replacement of moisture 
levels normally lost during cooling operations in storage, yet 
required to keep the stored crop in prime condition.

Controls for the humidifier unit are located in the remote 
control panel. The control panel is fitted with a door interlock 
isolator switch, for complete electrical safety and a selector 
switch providing Automatic Off and Manual Run selections. 
In the Auto Mode the unit operates intermittently with preset 
run and off periods. A simple timeclock controls the operation 
and can be set for almost any variation of On and Off periods.

Technical Details:

Base Unit         110cm (w) x 31cm (d) x 265cm (h)

Fan                   Normally utilises existing fans

Control Panel   Epoxy coated enclosure with door interlock
                         isolator Auto/Off/Manual selector switch and
                         24hr On-Off Timeclock.


Operation and Installation Instructions

Description of the Humidifier Operation

The Humidifier works by constantly dribbling water over a specially treated absorbent paper 
element. The element when fully "Wetted" provides a large evaporative surface area over which 
the air passing over the element can take up the  moisture. By constantly passing air over the 
element it is ensured that the air is at the maximum saturation at all times. As the air only takes 
up whatever water it can there is no danger of excess moisture being in the building. Any 
water not taken up by the air recycles safely within the humidifier housing water storage tank.

The Farm Electronics Humidifier operates virtually maintenance free and requires no operator 
settings apart from setting the Auto On & Off times. After extended operating periods the paper 
element may have to be renewed. This will be as a result  of water contamination deposits.
Under normal conditions the element life should be a minimum of 2 to 3 seasons dependant on 

It is recommended that the water tank is drained off at least once a fortnight to remove any
contamination from the recycled water. This will greatly extend the element life.

Operator Instructions

The control panel for the Humidifier is very simple in operation. The main switch has an 
AUTO / OFF/ MANUAL position. In MANUAL the Humidifier pump runs continuously. In 
AUTO the unit will run in times "Set On" on the timeclock on the panel.  Push the small pegs 
in to set "On Times", pull pegs out to set "Off Times". For maintenance the Main On / Off 
isolator at the bottom of the box can be used to gain access to the circuit breakers and fuses.

Optional Auto RH Control

It is possible to control the Humidifier on RH level demand if a separate RH controller is
fitted. (i.e. Farm Electronics Model CH1 or CH2)

In this case whenever the panel is switched to AUTO and RH falls below the set point the 
Humidifier is started up until the RH rises back above the set level. The inbuilt Timeclock
is overridden. However the Timeclock can still be set and used independently as before if 


Installation Instructions

The unit should be sited in the desired location. The feet can then be rag-bolted to the floor.
The base must be levelled using a spirit level. NB. It is very important that the unit is 
installed level. This is because the dribble bar must be level to obtain an even water flow 
over the element. Bolt the feet to the floor after levelling is complete. The pump motor and 
minimum water level cut off float switches are wired to the panel from the terminal box fitted 
to the module. Connect a suitable mains water supply to the ballcock in the water reservoir tank. 
It is recommended that a water isolation valve is fitted to allow future service isolation. Run 
the reservoir overflow pipe through to a point where water can be safely  discharged making 
sure that this has a fall to outside along its length. Connect a 240v ac single phase supply to 
the main switch of the control panel. The total load of the panel is 1.0amps. To set up the 
water flow rate, switch the unit to manual. Adjust the flow valve on the pump at the base of the 
unit at the front, to regulate the water flow from the dribble bar to a steady trickle over the 
whole length of the bar (normally this is factory set). This flow can be viewed by removing 
the cover plate at the top of the evaporative element assembly. Once these steps are complete 
the unit should be fully operational.

Case Study

Breathing New Life (and Lots more Air!) into a 32 year old North Norfolk Potato Box Store     ... read more ›

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