The NSS Pony 20 SCA is the largest walk behind carpet extractor that National Super Service produces. It has a large 20 gallon tank that allows the unit to clean large carpeted areas quickly and efficiently. Overall this is one of the best carpet extractors produced for the janitorial industry. Although this machine is extremely dependable and lasting, over time parts can breakdown and it may need to be repaired. The Pony 20 SCA is a simple machine with just five major elements that can fail. These elements are the gear excursion motor, vacuum motor, brush motor, pump and solenoid valve. It is quite simple to diagnose these parts and quickly repair them. When replacing parts on the NSS Pony 20 SCA is important to use OEM National Super Service parts to ensure that the machine runs correctly after repair.
The Pony 20 SCA is a self-excursion unit with variable speed that can cover large areas rapidly. The excursion system on this unit is powered by a 120 volt gear motor that powers the wheel assembly. The excursion motor is connected to the wheel assembly by a chain, if the excursion system goes bad and the machine does not move there are four elements which could be bad. The first and largest of these elements is the gear motor itself, this can be tested by running direct strength to the motor to see if it powers up. The second part is the speed control Board which increases or decreases the amount of voltage going to the motor depending on the speed at which the machine needs to run. On the lever assembly there is a dead man’s switch which turns the brush motor on and off. Over time switch elements can use down and fail and may need to be replaced. The last part that can fail is the circuit breaker, which over time can use out and prematurely overload. The circuit breaker is a three amp 120 volt unit that when overloaded will close the circuit to the brush motor. The other reason that this breaker will shutdown is if the brush motor is drawing more than 3 amps, this may be caused by bad bearings on the excursion wheel or something caught around the wheel impeding it from going forwards or backwards.
The Pony 20 SCA recovers solution from the carpet by an internal vacuum motor which sucks the water up by the vacuum shoe on the rear of the unit into the recovery tank. If you experience loss of suction it is important to check all seals and gaskets are clean and working condition. One of the main reasons for loss of suction is a damaged dome gasket located on the top of the machine. Any holes and fractures in this dome gasket will cause vacuum leaks and you will experience loss of suction. Before looking at the vacuum motor as a culprit also check the vacuum shoe and vacuum hose on the rear of the machine for any obstructions which may cause decreased suction. There are two main elements within the vacuum system. These two elements are the vacuum switch and vacuum motor. To find which part has failed use a multi meter to check to see if you are getting 120 volts to the vacuum motor when the switch is on. If you are getting 120 volts to the vacuum motor then the vacuum motor has prematurely gone bad. Other ways to tell if the vacuum motor is failing is to listen for a loud high-pitched squeal or grinding which would come from the motor bearings. On event water can get into the vacuum motor from the recovery tank if the machine is not emptied before the water level reaches the float valve. Other ways that water can get into the vacuum motor is excessive foam in the recovery tank from carpet cleaning detergents. One way to deter foam is to use a defoaming agent by adding it into the recovery tank before use. If you are not getting 120 volts to the vacuum motor when the switch is turned on, chances are the vacuum switch has failed and will need to be replaced. When replacing the vacuum motor in the Pony 20 SCA it is also important to replace the vacuum motor gasket to ensure a tight seal for optimal performance.
The next part which could fail is the brush motor. The brush motor on the Pony 20 SCA drives a rotating filament brush which is used to agitate the carpet fibers. This increases debris pickup and is optimal for food service areas and locations where dirt and grime are ground into the carpet. The number one reason that the brush motor will fail on this unit is if debris is caught up around the brush, or the bearings in the brush roll go bad. This will cause an excessive load be placed on the motor and it will use out prematurely. Another elements to check if the brush is not rotating is the brush belt, this belt could be slipping on the pulley or could be severed. If the brush is not rotating the three elements which could be bad are the brush switch, brush breaker or brush motor. To diagnose these parts take a multi meter and check for voltage coming from the brush switch to the breaker when the switch is turned on. If you are getting voltage to the brush breaker then proceed to the next step. Next check for voltage coming from the brush breaker to the brush motor, if there is no voltage there, then chances are your brush motor has failed. If you are not getting voltage from the brush switch to the brush breaker then replace the pump switch with an OEM NSS switch. If you are not getting voltage from the brush breaker to the motor and getting voltage from the pump switch to the brush breaker then chances are your brush breaker has failed and needs to be replaced. In the system there is also an AC rectifier which converts AC to DC strength for the brush motor. If the brush switch, brush breaker and brush motor are all getting strength then chances are the rectifier needs to be replaced.
The next internal system that could go bad is the pump system. The pump system sprays cleaning solution onto the carpet. If there is no solution coming out of your machine the first thing to check is jets on the lower end of the unit. There are five Jets on the Pony 20 SCA, these Jets are quick connect jets which when turned will break away from the jet housing. There is no need to unscrew the Jets from the spray bar. If you do need to replace the old jet housings be sure not to over tighten the jets as it will crack the plastic in the spray bar. To clean jets, soak in a delimer solution and then use compressed air to clear the jet nozzles. If the Jets are clean and you are not getting any solution on your carpet there are three elements which might have failed. These elements include the pump switch, pump or solenoid. To test which part has failed use a multi meter to check voltage between the pump switch and solenoid pump. If you are not reading any voltage from the system then chances are your pump switch has failed and will need to be replaced. If you are getting voltage from the pump switch to the pump then one of two elements could be bad. The pump and solenoid are attached together but the solenoid can be removed from the pump. On this unit the pump will run continuously run when the pump switch is engaged. The solenoid will open and close to allow water by the pump and then by the spray bar and jets onto the carpet. If you are getting strength to the solenoid and the pump and you are not hearing the pump run continuously than the pump will need to be replaced. If you are getting strength to the pump and the pump is running then the solenoid will need to be replaced.
Overall the National Super Service Pony 20 SCA is easy to continue and repair. There are other mechanical elements that may need to be replaced but this article covers the major elements that make the machine run. It is important not to touch live wires when diagnosing the machine. For optimal performance and reliability only use National Super Service parts when servicing this unit. NSS parts can be purchased from either a local dealer or online store. Our certified service technicians can assist you in finding the correct part for your floor equipment.