Rtech MTS251TFT User manual

www.r-techwelding.co.uk
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R-TECH MTS251TFT
DIGITAL MIG - MMA - DC TIG WELDER
OPERATION INSTRUCTIONS
Version 2023-12-V1

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3
Index
Page
Introducon 4
Safety Precauons 6
Electrical Installaon 7
Technical Specicaons 9
Connecons 11
Controls & Sengs 14
MIG EASY SETUP 19
MIG Manual Mode 20
DC TIG EASY SETUP 22
DC TIG Manual Mode inc. spot/tack 23
Memory Storing 28
MMA STICK EASY SETUP 29
MMA STICK Manual Mode 30
Fault Finding 32
Safety Informaon 33

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Thank you for selecng the R-Tech MTS251-TFT Digital MIG, DC TIG & MMA Welder.
The MTS251-TFT has many benets over tradional welders, including colour screen with easy
navigaon & EASY SETUP, 20 memory stores, MIG welding with oponal spool on gun, DC HF
TIG pulse welding with spot and tack funcons, remote foot pedal opon and an industrial 35%
duty cycle.
We want you to take as much pride in operang our MTS251-TFT Digital as much pride as we
have in making this product for you. Please read all informaon in this manual before operaon
PLEASE EXAMINE CARTON AND EQUIPMENT FOR DAMAGE IMMEDIATELY
When this equipment is shipped, tle passes to the purchaser upon receipt from the courier. Con-
sequently all claims for material damaged in shipment must be made by purchaser against the
transportaon company used.
Please record your equipment idencaon below for future reference. This informaon can be found
on data plate at rear of machine.
Product: MTS251-TFT
Serial No.
Date of Purchase
Where Purchased
Whenever you request replacement parts or informaon on this equipment please always supply
informaon you have recorded above
Pay parcular aenon to the safety instrucons we have provided you for your protecon The level of
seriousness to be applied to each secon is explained below
This statement appears where the informaon must be followed exactly to avoid serious per-
sonal injury.
CAUTION
This statement appears where the informaon must be following to avoid a minor personal inju-
ry or damage to this equipment.

5
Introducon
The R-Tech MTS251-TFT digital MIG - MMA - DC TIG welder is a member of our eld acclaimed family of
welding machines. Premium features include
Large TFT Screen
35% Industrial duty cycle
Inverter power source - more ecient
Electronic HF for fast arc starng in DC TIG and low interference
EASY SETUP MIG - MMA - DC TIG
Professional weld sengs built in
Sengs from 1.0 to 8mm pre-installed for easy setup
Simple to use easy navigaon - no complicated menus - all sengs on single screen.
MANUAL MODE DC TIG
Full control of every weld parameter you could ever need
Pre-ow gas, start amps, slope up me, main amps, slope down me, end amps and post ow gas
2 Start modes - HF Fast start & LIFT
2T, 4T, foot pedal & torch switch control modes
4TS trigger mode, Ideal for pipe welding, switch from start to main amps as required
DC Pulse up to 150Hz
20 professional memory stores
Spot welding - Spot weld feature with sch funcon
Fast Tack welding - Tack weld feature with stch funcon
Welding Capability – Duty Cycle
The R-Tech MTS251-TFT Digital is rated at 250 Amps at 35% duty cycle on a ten minute basis. If the duty
cycle is exceeded a thermal protector will shut machine o unl the machine cools.

6
Safety Precauons
Read enre secon before starng installaon.
Warning!
Electric Shock can kill – Only qualied personnel should perform this installaon. Turn o input power at
the fuse box before working on this equipment. Do not touch electrically live parts. Always connect the
machine to an earthed mains supply as per naonal recommended standards.
Select suitable locaon
Place the welder where clean cooling air can freely circulate in and out of the front & rear louvre vents.
Dirt, dust or any foreign material that can be drawn through vents into welder must be kept to a mini-
mum. Failure to observe these precauons can result in excessive operang temperatures which can lead
to plant failure.
Grinding
Do not direct grinding parcles towards the welder.
An abundance of conducve material can cause plant failure.
Transport & unloading
Never underesmate the weight of equipment, never move or leave suspended in the air above people.
Use recommended liing/handling equipment at all mes.

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Electrical installaon
WARNING ELECTRIC SHOCK CAN KILL
Electric Shock can kill – Only qualied personnel should perform this installaon. Turn o input power at
the fuse box before working on this equipment. Do not touch electrically live parts. Always connect the
machine to an earthed mains supply as per naonal recommended standards.
Machine grounding and High Frequency Interference Protecon
This welder must be grounded to earth. See naonal electrical codes for proper grounding methods.
The high frequency generator being similar to a radio transmier may cause interference to radio, TV and
other electronic equipment. These problems may be the result of radiated interference.
Proper grounding methods can reduce or eliminate this.
Radiated interference can develop in the following ways
1. Direct interference from welder power source
2. Direct interference from the welding leads
3. Direct interference radiated from feedback into power lines
4. Interference from re-radiaon by un-grounded metallic objects.
Keeping these contribung factors in mind, installing equipment as per following instrucons should
minimize problems.
1. Keep the welder input power lines as short as possible and enclose as much of them as possible in met-
al conduit or equivalent shielding. There should be a good electrical contact between this conduit and
ground (Earth).
2. Keep the work and electrode leads as short as possible. Tape the leads together where praccal.
3. Be sure the torch and earth leads rubber coverings are free from cuts and cracks that allow welding
power leakage
4. Keep earth lead connecon to work in good condion – Clean area on workbench where earth clamp is
situated on a regular basis.

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Electrical installaon cont.
Input Connecons
Make sure the voltage, phase and frequency of input power is as specied on machine rang
plate located at rear of machine.
Have a qualied electrician provide suitable input power as per naonal electrical codes. Make
sure machine is earthed / grounded.
Make sure fuse or circuit breaker is correct rang for machine. Using fuses or circuit breakers
smaller than recommended will result in ‘nuisance’ shut o from welder inrush currents even if
welding at low amperages.
Failure to follow these instrucons can cause immediate failure within the welder and void ma-
chines warranty.
Turn the input power OFF at the mains switch & fuse box before working on this equipment. Have
a qualied electrician install & service this equipment.
Allow machine to sit for 5 minutes minimum to allow the power capacitors to discharge before
working inside this equipment. Do not touch electrically live parts
The MTS251-TFT requires a 240V 50/60Hz supply. It requires a 32A supply. It comes with a 2.5
metre mains cable aached.
Connect wires according to naonal coding.
Brown wire – Live
Blue wire – Neutral
Green/Yellow Wire – Earth (Ground)
Connecng to an Engine Driven Generator
If connecng this machine to an engine driven generator please ensure the following
Minimum Generator KVA Output – 10 KVA connuous Generator to be ed with AVR (automac
voltage regulaon) DO NOT USE ON A GENERATOR WITHOUT AVR
Connecng to a generator without the above minimum requirements will in- validate your war-
ranty.

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Input 240V AC 50/60Hz Input amperage 32A
Gross weight 28 KG
Dimensions 470H x 280W x 640L (mm)
Insulaon IP21S
MIG Operaon Current range DC 30A - 250A
No load voltage 85V
Duty cycle 35% @ 250A, 60% @200A
MIG EASY SETUP - Programs for Wire Type - Mild steel .6mm 0.8, 1, 1.2, 1.5, 2mm
Wire Type - Mild steel .8mm 0.8, 1, 1.2, 1.5, 2, 3, 4mm
Wire Type - Mild steel 1.0mm 0.8, 1, 1.2, 1.5, 2, 3, 4, 5, 6, 7, 8mm
Wire Type - Stainless steel .6mm 0.8, 1, 1.2, 1.5, 2mm
Wire Type - Stainless steel .8mm 0.8, 1, 1.2, 1.5, 2, 3, 4mm
Wire Type - Stainless steel 1.0mm 0.8, 1, 1.2, 1.5, 2, 3, 4, 5, 6, 7, 8mm
Wire Type - Flux cored steel .8mm 1.5, 2, 3, 4, 5mm
Wire Type - Flux cored steel 1.0mm 1.5, 2, 3, 4, 5, 6, 8mm
Wire Type - Aluminium .8mm 1.5, 2, 3, 4mm (for spool gun)
MIG Manual sengs Pre-ow gas me 0 - 10s
Upslope 0 - 1s
Inductance 0 - 100
Spot me .5 - 15s
Stch me 0 - 15s
Burnback 0 - 2s
Downslope 0 - 1s
Post ow gas me 0 - 10s
Trigger modes Manual mode 2T,4T
Spool gun mode Yes
Technical specicaons

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DC TIG Operaon Current range DC 10A - 250A
No load voltage 78V
Duty cycle 35% @ 250A, 60% @200A
Arc starng modes HF, Li
Trigger modes Manual mode 2T,4T,4TS, REMOTE PEDAL,2T+F, 4T+F
Trigger modes EASY SETUP 2T,4T, REMOTE PEDAL, 2T+F, 4T+F
TIG EASY SETUP DC - Programs for Metal type Steel
Metal thickness programs 1.6 Tungsten 1, 1.2, 1.5, 2, 3mm
Metal thickness programs 2.4 Tungsten 1, 1.2, 1.5, 2, 3, 4, 5, 6, 8mm
TIG DC Manual sengs Pre-ow gas 0 - 10 seconds
Up-slope / Downslope me 0 - 10 seconds
Start / End amps 10A
Post-ow gas me 0 - 10 seconds
DC Pulse amps 3 - 95%
DC Pulse width (me) 5 - 95%
DC Pulse Hz 0.5 - 150 Hz
Memory sengs YES - 20
TIG DC Manual SPOT Mode Spot weld me 0.1 - 10 seconds
Spot weld stch me 0 - 5 seconds
TIG DC Manual TACK Mode Tack weld me 10ms - 250ms
Tack weld sch me 10ms - 250ms
MMA EASY DC - Programs for Rod types mild steel 6011, 6013, 7014, 7018
Rod diameter 2.4, 3.2, 4.0mm
2.4mm thickness programs 1.5, 2, 3, 4, 6mm
3.2 mm thickness programs 3, 4, 5, 6, 8mm
4 mm thickness programs 4, 5, 6, 8, 10mm
MMA Manual DC Amp range 10 - 200A
Duty cycle MMA 35% @ 200A, 60% @160A
An sck YES
Hot start me 0 - 2 seconds
Hot start % 0 - 100%
Arc Force 0 - 100%
Cellulosic Rods YES
Technical specicaons

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Connecons
Front panel connecons
MIG euro torch connector
MIG Spool on gun
connector
Quick release gas
torch connector
for TIG torch
MIG Mode - Spool
gun torch.
TIG mode - 7 pin
socket for TIG
torch switch or
remote foot pedal
Negave power con-
nector
MIG mode using gas
connect earth lead
TIG mode - connect
torch
MMA mode - connect
earth lead
Rear panel connecons
Fuse holder for water
cooler 240v output
Gas inlet 3/8 BSP ng.
TIG - Pure Argon
MIG Steel - Argon/Co2
MIG Alloy - Pure Argon
On/O switch
Posive power
connector.
MIG mode gasless
wire - connect
earth lead.
MMA mode -
connect electrode
holder
240v output for
water cooler
240v mains
input cable

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Rear panel connecons cont..
Extra earth connecon
Extra earth connecon, used if you experience local interference (not normally used)

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Wire feed assembly, wire reel holder & gasless wire
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4
1 - Wire reel retainer. Screw in to retain wire roll adaptor onto wire reel.
2 - Wire Feed Drive Assembly. To change roller size release retaining screw, remove roller and turn
roller around and slide onto sha making sure the right size groove is in line with wire and ret re-
taining screw. The MIG181 comes ed with a dual roller 0.6mm and 0.8mm.
3 - Roller tensioner - This sets the pressure of rollers, the best way to adjust tension is to slacken o
pressure so that MIG welding wire does not feed, slowly adjust pressure unl wire feeds
smoothly, you should be able to stop wire feeding by holding wire and it should slip on rollers.
If you have too lile pressure wire will slip when welding causing unwanted Burn back into ps or
errac weld beads size.
4 - When using gasless wire, move internal cable to negave connector – This then makes the torch
negave, you would then connect Workpiece earth lead to + posive connector on front of machine
3

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Front panel
Digital Colour Screen
Easy to navigate menu system - on previous digital machines, the sengs for ALL modes were on one
screen, now you only see sengs on screen for the mode you are using.
EASY SET mode - pre-programmed weld sengs for MIG - DC TIG & MMA
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345
1 - AMPS / Wire speed control knob
MIG mode controls wire feed speed / trim
MMA mode controls welding amperage
2 - VOLTAGE control knob
MIG mode controls welding voltage / trim
3 - Gas check buon / Save
To enable easy seng of gas ow.
SAVE buon - For saving manual mode memory sengs
4 - Control funcon selector knob
Turn to adjust and select seng, press in to set.
5 - EASY SET buon / Load
Press to enable / disable EASY SET mode
LOAD buon - For loading manual mode memory sengs

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Controls and sengs
The MTS251-TFT features 6 main operang modes
MIG in EASY mode
MIG in Manual mode
DC TIG in EASY mode
DC TIG in Manual mode
MMA (STICK) in EASY mode
MMA (STICK) in Manual mode
MIG EASY MODE
R-Tech Easy mode takes the guesswork out of MIG welding. You normally had to enter wire feed speed
and welding voltage before beginning to weld on manual welders, we have done this for you.
You simply select the following from easy to understand screen.
Wire diameter being used
Material thickness
The machine will set wire feed and welding voltage.
You can then trim the wire speed / voltage to suit your personal travel speed etc.
TO ENTER EASY MODE - PRESS EASY BUTTON ON FRONT PANEL - EASY HOME SCREEN WILL SHOW
MIG MANUAL MODE
In manual mode your have full control o all weld sengs
Wire feed speed
Welding voltage
2/4T Trigger operaon
Spool gun on/o
You can also adjust advanced features as below
Start / end amps
Pre and post ow gas
Up-slope and downslope
Spot and sch weld mer

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MMA EASY MODE
R-Tech Easy mode takes the guesswork out of MMA welding. You normally had to enter welding
amperage , we have done this for you.
You simply select the following from easy to understand screen.
Electrode diameter and type being used
Material thickness
The machine will set the required welding amperage.
You can then trim the voltage to suit your personal travel speed etc.
MMA MANUAL MODE
In manual mode your have full control o all weld sengs
Welding amperage
Hot start me
Hot start %
Arc force %

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DC TIG EASY MODE
R-Tech Easy mode takes the guesswork out of TIG welding. You normally had to set the welding
amperage before beginning to weld on manual welders, we have done this for you.
You simply select the following from an easy to understand screen.
Tungsten size being used
Material thickness
The machine will set the required welding amperage.
You can then trim the welding amperage to suit your personal travel speed etc.
TO ENTER EASY MODE - PRESS EASY BUTTON ON FRONT PANEL - EASY HOME SCREEN WILL SHOW
DC TIG MANUAL MODE
In manual mode your have full control o all weld sengs
Welding amperage
HF or Li start
2T/4T/4TS/2T+F/4T+F trigger modes
Pre ow gas me
Start amps
Up-slope me
Down-slope me
End amps
Post ow gas me
You can also adjust advanced features as below
Pulse mode on/o
Pulse me %
Pulse amps %
Pulse Frequency Hz
Spot / Tack mode
Spot / Tack me
Stch me

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Operaon
When you rst turn on machine you will see the following main funcon select screen.
Turn the middle selector knob to scroll through sengs available below, then press in knob to select.
MIG Ar95/C5 - MIG welding with MIG gas - most common.
MIG Ar80/C20 - MIG welding with industrial high thickness MIG gas.
MIG AL - Aluminium MIG welding with pure argon gas
MIG SS - Stainless steel MIG welding
MIG Flux - Gasless MIG welding
TIG DC - TIG welding with pure argon gas
STICK DC - MMA Sck welding

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MIG Operaon - EASY SET
Once you have selected required MIG mode you will see a screen as below.
This is the MIG manual screen.
Now press in the EASY SET buon and the following screen will be shown
Use the middle knob to cycle through sengs, when a seng is highlighted in red, use the le control
knob to change seng.
Wire diameter being used 0.6, 0.8,1 .0mm & Material thickness in mm
2/4T Trigger operaon & Torch Standard / Spool gun torch
Once you have selected the required wire diameter and material thickness, the recommended wire feed
speed and welding voltage is shown, you can trim both these sengs to suit personal travel speed etc.
To trim M/Min use middle knob to highlight M/Min in red, then adjust using le knob.
To trim Voltage, use right side control knob.
Spool gun operaon - when using spool gun, the knob on gun itself trims / controls the wire feed speed.

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MIG Operaon - manual mode
Once you have selected required MIG mode you will see a screen as below.
This is the MIG manual screen.
Use the middle knob to cycle through sengs, when a seng is highlighted in red, use the le control
knob to change seng.
Wire feed speed
Welding voltage
2/4T Trigger operaon
Spool gun on/o
Spot welding on/o
Once you have selected the required base opons, you can then move to advanced sengs screen by
highlighng the icon below and pushing in middle knob.
Spool gun operaon
When using the spool on gun, the control knob on the gun controls the wire feed speed.