Truck Mount Startup and Shutdown Standard

Purpose

A truck mount is an industrial engine, a positive displacement vacuum blower, a high pressure plunger pump and a heat exchanger on one drive and one water path. Brought up in the wrong order it damages itself quietly: heat before flow bakes scale onto the exchanger tubes, a blower engaged on a low oil reservoir scores its lobes in minutes, a plunger pump run dry loses its cups in one job. Put away in the wrong order it does the same in reverse, and a unit parked full of water on a night below freezing splits a pump head: a multi-day repair and a route handed to somebody else's truck.

This standard fixes the order, gives every step an acceptance number off a gauge or a thermometer, and puts the freeze call on the published forecast rather than on how cold it felt at the last stop.

Scope

Covers daily startup, in-job monitoring, shutdown and end-of-day freeze protection on a gas engine slide-in or PTO truck mount doing residential and light commercial hot water extraction.

Does not cover: oils, belts and hour-based service (truck mount PM SOP); exhaust placement and carbon monoxide monitoring (the CO SOP, which gates step 1 here); jet and vacuum path service; filling and waste disposal; portables (the high-rise setup SOP). A unit past its PM interval does not run on this SOP - that is a shop manager call.

Roles and responsibilities

Procedure

1. Set van position and exhaust before anything runs. Park level or nose-up, chock the downhill wheel, set exhaust distance and direction under the carbon monoxide SOP, clip on the personal CO monitor. Accept: chock in, brake set, monitor self-tests with its calibration date in the future, exhaust path clear to open air. Wrong: an overdue calibration date, or the only spot puts exhaust under a soffit or into an attached garage. Stop rule: no monitor, no start, and no truck mount runs in or under an enclosed structure. Hazard: engine exhaust is odorless and it is what kills people on this van, so the monitor is the control and position alone is not.

2. Do the cold fluid and guard check with the key out. Engine oil between the marks, coolant at the cold fill line in engine and exchanger loop, blower oil at the full-cold sight line, belt guards fastened. Accept: all four at or above their marks, each guard on both fasteners. Wrong: blower oil under the sight line, or a guard on one screw. Stop rule: low blower oil is a red tag, not a top-up - the reason it is low is a seal, and it will be low again inside the shift. Hazard: do this cold with the key in your pocket: a hot blower case burns on contact, and a belt that starts with a hand behind a guard takes fingers.

3. Establish water and prime the pump before heat exists. Connect the fill under the fresh water fill SOP, fill the onboard tank to its line, clear the inlet screen, run the pump on bypass. Accept: a solid unbroken stream at the wand for 15 seconds with no spitting, tank at or above its fill line, and a fill source that keeps up with the machine's demand, about 2.5 gallons per minute on a single-wand truck mount - time 5 gallons into a marked bucket. Wrong: a pulsing or spitting stream, which is air, not a weak pump. Stop rule: stop the pump, find the air at the inlet screen or a loose fitting, never go to heat unprimed. Hazard: the wand points into the waste tank opening, never at a hand or foot - a cold plunger pump at working pressure injects through skin, and that wound looks like a pinprick and is a surgical emergency.

4. Start at idle and let it stabilize before loading it. Crank, then leave it at idle a full 60 seconds. Accept: steady idle for 60 seconds, no miss, oil pressure up, no new noise. Wrong: a hunting idle or a knock. Stop rule: shut down and call the shop manager rather than load a rough engine. Hazard: exhaust exists from the first crank and the monitor is live from here on - an alarm takes the CO SOP response, not a restart.

5. Engage the blower and read vacuum at the reel. Accept: vacuum at the reel inside the band the shop manager set for that machine and hose length, wand valve closed. Wrong: a low reading with the hose capped, meaning a leak in the recovery path, or a blower that howls or rattles. Stop rule: a rattling blower shuts down at once, because the failure after noise is a seized rotor that takes the drive with it; a low capped reading goes to the vacuum and jet SOP before the job, not after. Hazard: the open vacuum inlet pulls in a cuff or glove finger, so hands stay off it while the blower is engaged.

6. Bring solution pressure up with the wand triggered into the waste tank. Set the shop's pressure for that wand and jet set. Accept: the gauge reaches set pressure in about 10 seconds and then holds steady rather than sawing. Wrong: a needle sawing by more than a few percent of set pressure, which is a failing cup or stuck unloader. Stop rule: a sawing gauge is a pump fault, and the unit does not touch a customer's carpet - red tag and report. Hazard: stored pressure now exists in over 100 ft of hose, so nobody stands over a coupler while it comes up and the operator's face turns away from the tank opening.

7. Heat on only after flow, then verify temperature in the line rather than at the machine's own gauge. Take the reading under pressure, at the wand inlet or the machine outlet port: water leaving the jet is back at atmospheric pressure, where it flashes near 212 degrees F at sea level, so a free-stream reading cannot reach the in-line band however hot the machine is. Accept: in-line temperature reaches and holds the shop's working band, commonly 210 to 230 degrees F on synthetic carpet, within 5 minutes of heat coming on; where the only reading available is a tip reading into the waste tank, the field proxy for that band is 205 to 210 degrees F. Wool and other protein fibers run much lower and the fiber SOP governs there. Wrong: a reading that climbs then falls back, which is exchanger scale or a starved supply, not a bad thermostat. Stop rule: a fallback of more than 20 degrees F while running drops the job to no-heat and sends the unit for descaling. Hazard: water in that band scalds on contact and the tip stays hot after the trigger closes, so a tip reading goes into the waste tank opening, gloved, never a bare hand under the tip.

8. Monitor at every tank change. Re-read vacuum, pressure and water temperature, and check the waste tank float. Accept: all three inside their bands, waste level below the float shutoff. Wrong: vacuum falling steadily through the job, which is a filling tank or a loading lint screen rather than a dying blower. Stop rule: vacuum below band stops wand passes until the tank is dumped and the screen cleared, or you leave water in the carpet and buy a slow-dry callback. Hazard: opening the waste tank puts hot, biologically loaded aerosol at face height - stand upwind, lid between you and the opening, gloves on.

9. Shut down in reverse: chemical off, flush, cool, unload, idle, stop. Close the chemical feed, run clear water 30 seconds, turn heat off and keep water moving until the wand reads under 120 degrees F, unload the blower, idle 2 minutes, key out. Accept: clear water at the end of the flush, wand under 120 degrees F, 2 minutes of idle before the key. Wrong: killing a hot engine with the exchanger full, which cooks residue onto the tubes and is the usual cause of the step 7 fallback a month later. Stop rule: if the engine dies hot, restart and finish the cool-down. Hazard: exhaust and exchanger stay hot after shutdown, so nothing is stowed against either and the CO monitor stays on until the engine has been off 5 minutes.

10. Make the freeze call on the forecast, then restore every valve you opened. If the overnight low where the van parks is forecast at or below 32 degrees F, empty the waste tank first under the waste disposal SOP, then draw propylene glycol RV antifreeze through pump, solution line, hose and wand until colored fluid shows at the wand and at the relief return. Accept: color at both discharge points, and the fresh tank drain, exchanger drain and waste tank drain each closed again by hand - three valves opened, three closed. Wrong: antifreeze drawn only as far as the pump, leaving reel and wand wet; a hose full of ice splits its inner tube and leaks mid-job a week later. Stop rule: too little antifreeze on the van to see color at both points means the unit does not park outside. Hazard: propylene glycol is far less toxic than ethylene glycol but is still an ingestion hazard to pets and children, so nothing drains onto a driveway.

The record this produces

Each startup writes one line in the unit log, kept on the van and synced to the job record: date, engine hours at start, blower oil level, primed yes or no, vacuum at the reel, set pressure, water temperature with where it was read and the minutes to band, waste dumps, engine hours at shutdown, and freeze protection yes or no with the forecast low. Any step that took a stop rule records the step number, the failing reading, and who was told.

The shop manager reads the temperature column across a month to catch scale before a no-heat day: a unit that banded in 3 minutes in March and takes 4-1/2 in May is scaling, still inside step 7's 5 minute gate and invisible in any single day's entry.

Worked pass, with a step that failed

Residential job, three rooms. Van 25 ft from the front door, downwind, monitor on, chock in. Step 2: oil mid-range, both coolant loops at the cold line, blower oil at full-cold, guards fastened. Step 3: primed, solid stream 15 seconds. Step 4: steady idle 60 seconds. Step 5: reel vacuum in band at 125 ft of hose. Step 6: set pressure in about 8 seconds, holding, no saw.

Step 7 failed. The van carries no outlet port, so the reading was the tip proxy: the thermometer in the stream at the waste tank read 190 degrees F at 5 minutes, then fell to 165 degrees F over the next 4 minutes. The proxy floor is 205 degrees F, so 190 never reached it, and 190 minus 165 is a 25 degree F fallback, past the 20 degree F limit in the step's own stop rule. Both halves of the acceptance failed.

The tech worked the stop rule instead of turning the heat up. Supply was checked first, since a starved exchanger falls back the way a scaled one does: the fill hose put 5 gallons into a marked bucket in 1 minute 40 seconds, and 5 gallons over 1.667 minutes is 3.0 gallons per minute, above the 2.5 gallons per minute step 3 sets for this machine, so supply was not the cause. That left scale. The job finished at no-heat with a stronger prespray and longer dwell, the customer was told dry time would run long, and the unit went for descaling that evening.

Shutdown ran clean: chemical off, 30 second clear flush, heat already off, wand under 120 degrees F, blower unloaded, 2 minute idle, key out. Forecast low was 41 degrees F, above the 32 degree F trigger, so no antifreeze was drawn and no drain valve opened - which is why step 10's restore count for this run is zero valves, not a skipped check.

References

• See related: Prochem Everest 650 Truck-Mount Preventive Maintenance SOP - owns oils, belts and the hour-based intervals this SOP defers to.
• See related: Carbon Monoxide and Exhaust Safety on a Truck Mount SOP - gates step 1, owns the alarm response.
• See related: Vacuum and Jet Maintenance Standard SOP - owns the capped vacuum test and the jet service used in steps 5 and 7.
• See related: Waste Water Disposal and Fresh Water Fill SOP - owns the fill in step 3 and the tank dumps in steps 8 and 10.
• Manufacturer operating manual for the unit, which sets the pressure, vacuum, flow and temperature bands this SOP asks the shop manager to record per machine.