How Do You Set Up an Old Guardian PET1481A Time Delay Relay?

Issue:

I have an old Guardian PET1481A timer. How do you set it up? Do you offer a replacement product for this obsolete unit?

Solution/Resolution:

Macromatic used to build the PET1481A time delay relay under contract for Guardian Electric Manufacturing Company, but we stopped back in 2003.

Since we built & sold the product to only Guardian, we do not normally provide any technical support. However, we offer this KnowledgeBase article as a service to anyone needing help in setting up the PET1481A product. We CANNOT provide any information beyond what is included below, nor can we answer any service questions related to the product. For a substitute product, see the last paragraph below.

To set-up the PET1481A unit, please refer to the following steps & the diagram above which is also on the side of the product:

• All set-up is done with the 9 DIP-switches on the side of the unit & the potentiometer on the top.
• To set one of the four built-in functions-On Operate (On Delay), Release (Off Delay), Interval ON & OP/Release (Retriggerable Single Shot)-set DIP-switches #2 & #3 per the chart. NOTE: if you select either the OFF Delay or Retriggerable Single Shot functions, you must set DIP-switch #9 to ON.
• Set DIP-switch #1 to OFF to select a Basic Time Range of 0.3-1.75 SEC or ON to select a base time range of 47-260 SEC.
• The actual time range is equal to the base time range selected with DIP-switch #1 in the previous step times N. The value of N is determined by setting selected DIP-switches #4-#8 to the ON position, then summing the values. The value of N is then multiplied times the Basic Time Range selected with DIP-switch #1 to give you a total Time Range. You can adjust your time delay between the MIN & MAX settings of the total Time Range using the potentiometer on top.
• For example, let's say you selected a Basic Time Range with DIP-switch #1 of 0.3-1.75 SEC. If you move DIP-switches #4 & # 6 to ON, the corresponding values of 16 & 4 totals an N value of 20. Then take this N value of 20 times the Basic Time Range of 0.3-1.75 SEC. This gives you a total Time Range of 6-35 SEC. You can adjust your actual time delay using the potentiometer from a MIN of 6 seconds to a MAX of 35 seconds.

Since the warranty for these products has expired a long time ago, we suggest you seriously consider buying a new device. The Macromatic substitute would be either our TD-781 or TD-881 Series products-click on the links for further information. NOTE the following differences between the PET1481A and these substitute products:

• The PET1481A can be used on either 24V or 120VAC input voltages depending which of three terminals you used-both the TD-781 & TD-881 Series products are 24V only or 120V only
• The PET1481A is an analog set unit while the TD-781 & TD-881 Series products are digital-set
• The PET1481A has only four functions-the TD-781 has 10 functions and the TD-881 has 16 functions