Warrick Series 27 Part Number
Configuration Explained

The 27 Series liquid level controller is designed with mounting tabs to install within a panel or enclosure for use with float-type or conductive probe-type level sensors. It can be configured for single level indication (e.g. high alarm), or for pump up or pump down differential service. It is designed for applications where intrinsically safe control with UL and CSA approval may be required.

Mode of Operation

“Mode of Operation” covers whether your control will be direct acting or inverse acting. The way the operation behaves is different when functioning as single or differential service as described below.

Single level service

                                                                                                                  

Direct acting refers to the state of the normally open (NO) contacts in relation to rising liquid level. The contacts remain open while liquid is below the high-level probe connected to the (L) terminal (with jumper between L & H ) on the 27 series screw terminals. These NO contacts then remain closed only while liquid is in contact with the high-level probe.

Inverse acting refers to the state of the normally open (NO) contacts in relation to rising liquid level. The contacts remain closed while liquid is below the high-level probe connected to the (L) terminal (with jumper between L & H) on the 27 series screw terminals. These NO contacts then remain open only while liquid is in contact with the high-level probe.

Differential level service

                                                                                                                   

Direct acting, commonly called “pump down” or “drain” refers to the state of the normally open (NO) contacts in relation to the liquid level between the high and low probe ends. When liquid reaches the high-level probe connected to the (H) screw terminal on the 27 series, the contacts close. They remain closed until liquid level falls below the low-level probe connected to the (L) screw terminal on the 27 series. Once it falls below the low-level probe the NO contacts open and remain so until reaching high-level probe, repeating the process.

Inverse acting, commonly called “pump up” or “fill” refers to the state of the normally open (NO) contacts in relation to the liquid level between the low and high probe ends. When liquid falls below the low-level probe connected to the (L) screw terminal on the 27 series, the contacts close. They remain closed until liquid level rises to contact the high-level probe connected to the (H) screw terminal on the 27 series. Once it reaches the high-level probe the NO contacts open and remain so until falling below the low-level probe, repeating the process.

Supply Voltage

The supply voltage selection is what is used to power the control module (attached to both AC terminals and G ground).

Sensitivity

The general rule is the sensitivity of the control (e.g. 10K, 100K etc.) should be greater than the resistance of the liquid. The less conductive (more resistance) a liquid is, the more sensitive the control module needs to be. It is usually better to choose the sensitivity level that is above, yet as close to the conductivity/resistance as you can. Choosing a level too high could sense mist, foam, steam, etc., or even cause the module to not operate properly. Gems has offered a conductivity chart <HERE>.
Please note, if your liquid conductivity is too high for any sensitivity level listed, then you will need to consider a float-type level sensor.

Enclosure

You can choose to have the control module affixed within a 6x6x4 fiberglass NEMA rated enclosure.

Type 1 enclosure constructed for indoor use to provide a degree of protection to personnel against access to hazardous parts and to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (falling dirt).

Type 4 offered is type 4X enclosure constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (windblown dust); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); that provides an additional level of protection against corrosion; and that will be undamaged by the external formation of ice on the enclosure.