The most common reason for your hot glue system acting up is because of a clog. Clogs are common because you are working with glue, which is sticky and chars over time. Below are some of the most common technical calls we receive, with the solution…and you guessed it, it’s usually always a clog.

Pump is not pumping

There are several reasons as to why your pump can stop up. Honestly, it is usually dirty oily air in your shifter. However, when it is not your shifter it is usually a clog. If your shifter is running fine, but it sucked something up into the hydraulics of the pump, the pump shifter will be stopped in the top position, unable to shift down. That is because you probably have some char or debris in your hot glue reservoir and while pumping, you sucked something up into the ball check valve. You have now clogged up your pump and need to send it in for a flush and clean. Another potential issue could arise if your pump is running but sluggish. If your pump is running mush slower than it used to, it is probably because you haven’t changed out your tank filter and it is clogged. The tank filter is located on the side of the tank and filters all glue before it runs into the hoses. If that filter is not regularly changed (every 500 – 1500 hours depending on how clean your glue is) then that clog can cause pressure to back up into the tank and not allow your pump to run at full capacity.

Gun is not firing

If your gun is not firing at all, it is probably your solenoid valve. However, if your gun is firing every other time or randomly, it is probably due to a clog in your in-line filters. The in-line filters filter the glue from your hoses into your gun. These filters are there to help filter our char or debris that was missed by the tank filter or that has built up in the heated hose. If the filter screens are not changed regularly, they will get clogged up and not allow for your gun to fire properly. For example, if you need to increase air pressure in order for your gun to fire, it is probably the in-line filter clogged up. Another clog can happen in the gun manifold itself. Typically, this is only in multi-module guns. If you have a multi-module gun and the last module in the line is not firing, there is probably a clog in the manifold.

Module Drips

If your module is constantly dripping glue, then you have a clog in your module. This is most common in air open, spring close modules. A piece of char will get stuck in the seat and not allow the piston to seal tightly, causing the glue to drip out. A clogged module will need to be replaced with a new module.

Nozzle keeps clogging

This one is fairly straight-forward. If your nozzles keep clogging there are a few solutions. First, you can change out your in-line gun filters. They are probably not clean and not filtering the glue through the gun. You can also increase your nozzle diameter. If you are running small hole nozzles such as .010 or .012 diameter, try a .014 or .016 and you will start to see less clogging. However, that will lay down a little more glue, so keep that in mind when reviewing your glue usage.

The best way overall to reduce the number of clogs in your hot melt systems is to do preventative maintenance. That means cleaning your tank every month or every quarter, depending on how many shifts your tanks are running. Universal Systems makes Purge Plus tank cleaner and we sell them in a 5-gallon pail so that you are set for at least 2 – 3 cleanings. Additionally, change out your tank filters and in-line filters. These 3 tips are the most inexpensive way to keep your hot melt system running smoothly.