Technical Helpdesk


We are proud to say that all our pumps are designed by people with extensive knowledge of the air conditioning industry. We are always happy to answer your questions by phone or email, but do please browse some of the already answered questions here on our FAQ page:

You can contact our help desk at:
(+44) 01323 848842

I have 2 black wires with your pump, what do I do with them? (this also applies to mini pumps where there are 3 wires Grey Purple Orange)

A) To control the AC, wire into the appropriate control circuit provided in the AC equipment (this will require the AC circuit diagram, make sure power is OFF)

If this control is not required, the black wires are volt free as received from Aspen, (no voltage will be present on the black wires when the pump is working) the wires can be cut off or taped up if not required, Aspen strongly advises the use of a high level safety device to prevent damage in the event of pumps failure or over filling. The high level safety can be used in conjunction with BMS systems; there is an unused terminal available inside the pump (High Flow, High Lift & Heavy duty types), which can also be utilised. In the case of Mini Pumps all 3 terminal are wired N.O, normally open, N.C, normally closed, C. Common. Here again these are volt free. In all cases the maximum load is 4amps.

Any electrical work should only be undertaken by trained professionals.

How far will it pump?

A) Ideally pump as short a distance as possible for best pump efficiency, the best set up is to utilise an internal gravity drain system with a "Tun Dish" for each pump.

If this is not possible keep the discharge tube line as short as possible, all pumps as delivered have a performance graph giving flow rates in vertical head.

If long horizontal runs are required installers should satisfy themselves that the system can cope with maximum amounts of condensate which are likely, a simple rule of thumb, most AC systems will produce about 0.5 - 0.75 litres of condensate per KW/Hour, dependant on relative Humidity RH.

My Mini Lime is Noisy? (This could equally apply to all mini pumps)

A) Check where the discharge line goes?

  • Does it go to an outside drain at ground level?
  • does the end of the line end below the pumps?

If the answer is yes to the above the condensate is most likely siphoning out of the system after the pump has stopped working, this causes the pump to prime itself every time it starts, this process is noisy as the pump has to pump some air at first, gradually over a period of time this leads to the pump being weakened and becoming noisy all the time.

The discharge line must be setup to prevent siphoning. Aspen provides an Anti Siphoning Device with all their Mini Pumps and Silent+ Range.

My Aspen Universal runs all the time, how long is the timer set for?

A) The timer is 3 minutes, however, there is hysteresis to be accounted for Hysteresis, the time it takes for the blue (cold air sensor) to equalise in temperature to the red (ambient sensor).

In most modern split or ductless systems the indoor wall unit has a motorised Louvre blade which closes when cooling ceases, this closing holds large amounts of cold air inside the unit keeping the sensor at below ambient, even 1 degree difference is enough to keep the pump working. Try switching to "Fan Only", clear the cold air from the unit, after a short time (about 5 minutes) the pump should stop.

Alternatively warm the blue sensor in your hand after a few minutes the pump will stop.

What is the temperature differential of the universal sensors?

A) 5 degrees

I have an Aspen Standard, What do I do with the black wire, and it only runs for 3 minutes when I turn it on?

A) The black wire is a trigger, it requires a voltage be applied to it to energise the pump while the system is in cooling, without this trigger the pump will run 3 minutes and stop (timer)

The black wire should only be energized when the system is cooling, a suitable trigger can be from the compressor live or in the case of a heating system the reversing or change over valve may have a suitable voltage applied while in cooling this can also be utilised.

Standard pumps are very versatile, the trigger can be applied via a relay, float switch or some other device such as a timer, so enabling the pump to be adapted to a wide range of applications including dosing, lubrication, we have even supplied them to the printing industry for inks, to laboratories for chemicals, they have been used on ships, and on railways.

The trigger can be 150 - 240 Vac, lower voltages will give inaccurate or non-existent energisation.

I have an Aspen Peristaltic Pump and the head tube keeps failing?

A) There are 2 main reasons for failure, either:

  • The tube is contaminated with some sort of mineral oil (typically this can be compressor oil in the even that refrigeration has leaked in the system of someone has inadvertently used mineral instead of silicone grease) with this type of failure the tube enlarges and becomes much larger than original and gets damaged in the rotor.
  • If some abrasive material such as cement or plaster debris has been left inside the unit after installation and gets drawn inside the tube this then cuts the tube from the inside.