MiTM 3500-4000 PSI Pressure Washer 2017 Unloader Handle / Knob Replacement

Introduction

In this guide, we will source and replace the plastic Unloader Handle / Knob that is prone to cracking from frequent use and abuse in more extreme environments and conditions. In some 2017 MiTM 3400-4000 PSI pressure washers, the discontinued [RKV 4G37 D] pump is used, and can be identified by the silver label on the gold-colored pump-head on the pump of the pressure washer that has the “RKV 4037 D” marking on it, as well as the serial number of the pump, and the “Annovi Reverberi” name and logo. We can then identify the Unloader Assembly model number, and then find the Unloader Handle / Knob part number from there using the Annovi Reverberi parts breakdown pages.

Step 1 Unloader Handle / Knob

MiTM 3500-4000 PSI Pressure Washer 2017 Unloader Handle / Knob Replacement, Unloader Handle / Knob: step 1, image 1 of 2

MiTM 3500-4000 PSI Pressure Washer 2017 Unloader Handle / Knob Replacement, Unloader Handle / Knob: step 1, image 2 of 2

First, identify your pump. If your pump looks like this, it is likely an Annovi Reverberi pump, as they were used on some MiTM 3500-4000 PSI pressure washers.
If your pump does not look like this, then you are likely in luck, and the iFixit diagrams and part numbers for your pump should be accurate.

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Step 2

Then, identify the model number on the silver sticker on the gold-colored pump head.
It should say "RKV 4037 D", however in usage this is the same as the model [RKV 4G37D] or [RKV 3400 RPM Series D RKV4037] which can be found as a replacement part, and often comes with an unloader valve, though it is not always included, and often includes a different unloader valve from the original pressure washer.
This part is not listed in the iFixit page for this pressure washer, and is shown incorrectly in the diagrams, as is the unloader valve.
If you just need to replace the pump, here is the exact model you will need, with the unloader valve: https://www.ppe-pressure-washer-parts.co...

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Step 3

MiTM 3500-4000 PSI Pressure Washer 2017 Unloader Handle / Knob Replacement: step 3, image 3 of 3

Identify the unloader valve. It should be on the input ports of the pump head, and usually has a gold-colored body.
The top port should have the valve stem of the unloader valve, as well as the spring, two (2) jam nuts, and the spring washer.
The front port should contain an adjustment plug with a hexagonal indent.
The back port should be connected to the water input passthrough, or as pictured here, to a reinforced hose that goes to the water input passthrough below the unloader valve.
The left port should be connected to the output of the pump, or a quick-connect for the pressure washer hose, as pictured here with a 90 degree elbow.
The right port should be connected to the uppermost port of the pump head, or the main output on the pump head.

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Step 4

The schematic for assembly and disassembly outlines the order of parts to go onto the valve stem, including the unloader handle.
The most standard unloader valve featured on this pump is the VRT3-310, however the included PDF includes the schematics for all of the VRT3 models. If your pump unloader does not look like this, you can search for it on the Annovi Reverebi website here: https://www.arnorthamerica.com/pages/par...
It also provides reference numbers in the legend below the schematic of the attached document "VRT_2015.pdf" that we can use to order an replacement parts that we may need to repair the unloader valve, as the iFixit schematic for the unloader valve and unloader handle has the incorrect part numbers for this pump.