DrawWarm

Gallery

Inside the simulator

Every picture here is a screen from the DrawWarm simulator, captured on 5 November 2026. The menu tour comes first, in the order a new learner meets it. Select any picture to see it larger.

The menu tour

Start to finish, menu by menu

From the start screen to Help, in the order a new learner meets them.

  1. 01 · The start screen
    The start screen: four ways in, the Programme, Sandbox Mode, Lessons and Random Fault.
  2. 02 · The Programme
    The DrawWarm Programme, stage by stage: Foundation, Intermediate, Advanced and Champion, with your record underneath.
  3. 03 · Foundation, unit by unit
    Foundation opens its units in order, each with what it covers: first the simulator itself, then reading a circuit.
  4. 04 · Quick Jobs
    Quick Jobs: short guided jobs, such as proving dead before you start or adding a second heating zone.
  5. 05 · Worcester wiring
    The Worcester wiring course: circuits wired as the boiler maker’s installation pages show them, on boilers based on Worcester models.
  6. 06 · Random Fault
    Random Fault: choose Easy, Medium or Hard, and the simulator hides a fault in a working circuit for you to find.
  7. 07 · The parts list
    Sandbox Mode’s parts list at Programmers & Timers: each part, with the makers’ units based on it listed underneath.
  8. 08 · Load Example
    File, Load Example: S-Plan, Y-Plan, combi, branded and Worcester circuits, each ready to switch on or rewire.
  9. 09 · An example loaded
    The S-Plan example loaded onto the canvas, wired and switched off: press Simulate and it runs.
  10. 10 · Export and share
    File, Export: the circuit as a picture, a PDF with its terminal schedule, or a link to share.
  11. 11 · Settings
    Settings: sound and music volume, and the size of the text.
  12. 12 · Help
    Help, built in: getting started, the tools, wiring, the multimeter, S-Plan and Y-Plan explained, safety and a glossary.

Systems

Wired, and switched on

S-Plan, Y-Plan, combi and more, each wired in the simulator and running: valves open, the pump turns, the live wires light up.

  1. S-Plan, running
    An S-Plan switched on with heating and hot water calling: both zone valves open, the pump running, the boiler firing.
  2. S-Plan, ready to wire
    The same S-Plan’s parts placed and unwired, the wiring centre’s numbered blocks still empty.
  3. S-Plan Plus
    S-Plan Plus: two heating zones and hot water on three 2-port valves, with DrawWarm’s own heat-only boiler.
  4. The wiring centre, live
    The S-Plan’s wiring centre close up while the system calls, every core in its colour on its numbered block.
  5. Y-Plan, running
    A Y-Plan switched on with heating and hot water calling, its 3-port valve at mid-position and the pump running.
  6. Combi, two heating zones
    DrawWarm’s own combi with two heating zones: each room stat opens its own 2-port valve.
  7. C-Plan
    A C-Plan: pumped heating and gravity hot water, with a valve based on the Honeywell V4043H (6-core).
  8. Underfloor and radiators
    Radiators and an underfloor heating zone on one system, both zones calling, with DrawWarm’s own heat-only boiler.
  9. OpenTherm, two zones
    An OpenTherm two-zone receiver on DrawWarm’s own system boiler, both zones calling.
  10. Three zones, one system boiler
    Three zones on DrawWarm’s own system boiler, with controls based on the Danfoss FP715Si, Honeywell T6360B and Drayton HTS3.

Makers’ units

Units based on makers’ products

Programmers, stats, receivers, valves and boilers based on makers’ products, each with its own terminals to read and wire. DrawWarm’s own designs say so.

  1. Every maker’s unit
    Every unit in the simulator based on a maker’s product, side by side, with DrawWarm’s own designs among them.
  2. Programmers and timeswitches
    Programmers and timeswitches based on units by Drayton, Honeywell, Danfoss, Horstmann, ESi, Salus and other makers.
  3. Zone valves
    2-port and 3-port valves based on Honeywell, Drayton, EPH Controls and Sunvic valves, each with its own head.
  4. Boilers
    Boilers based on Worcester and Vaillant models, beside DrawWarm’s own combi, heat-only and system boiler designs.
  5. Drayton
    Units based on Drayton’s: LP programmers, a cylinder stat, wireless stats and receivers, and a 2-port valve.
  6. Hive
    Units based on Hive’s thermostats and receivers, wired in the simulator like any other control.
  7. Same S-Plan: Drayton LP722
    The same S-Plan with a programmer based on the Drayton LP722: the same blocks, its own printed terminals.
  8. Same S-Plan: Danfoss FP715Si
    The same S-Plan with a programmer based on the Danfoss FP715Si fitted instead.
  9. Same S-Plan: Honeywell ST9400C
    The same S-Plan again, now with a programmer based on the Honeywell ST9400C.
  10. Drayton LP722: the backplate
    A programmer based on the Drayton LP722, its backplate and its front: read the terminals before you wire.
  11. Worcester 27Ri: the terminal strip
    The terminal strip of a boiler based on the Worcester Greenstar 27/30Ri, wired into an S-Plan.
  12. Worcester Greenstar 4000: the terminals
    The terminals of a combi based on the Worcester Greenstar 4000, opened up in the simulator.
  13. Google Nest: the Heat Link
    A thermostat and Heat Link based on the Google Nest units, the Heat Link’s terminals open.
  14. Combi with a wireless stat
    A combi based on the Worcester Greenstar 4000, with a wireless stat and receiver based on the Drayton Digistat+RF.
  15. DrawWarm’s own designs
    DrawWarm’s own designs: two cylinder stats, a combi, a heat-only boiler and a system boiler, drawn for the simulator.

Makers’ names and model numbers are trade marks of their owners, used only to say which product a unit is based on. DrawWarm is not affiliated with, or endorsed by, any maker named on this site.

The DrawWarm Method

Block by block, in the order of the numbers

The wiring centre is filled in the order of its numbers, so the diagram makes sense, and the same order finds a fault.

  1. The numbered blocks
    The wiring centre’s numbered blocks close up. Each block joins only the wires landed on it.
  2. Block 1: the permanent lives
    The DrawWarm Method on an S-Plan, lesson 1: block 1 first, the permanent lives, with the lesson beside the canvas.
  3. Blocks 1 and 2 wired
    As lesson 3 opens, blocks 1 and 2 are wired: the permanent lives and the neutrals. Next, the earths on block 3.
  4. Blocks 1, 2 and 3 wired
    Lesson 4 opens with blocks 1, 2 and 3 done. Next, the heating: blocks 4 and 5.
  5. Heating and hot water wired
    Lesson 6 opens with heating and hot water on blocks 4, 5, 6 and 8. Next, block 10: the oranges, boiler and pump.
  6. Commissioning: the truth table
    Lesson 7, commissioning: each demand is tried in turn, and the system must do what each one asks.
  7. The same order finds a fault
    Tracing in block order: 230 V on block 4, 0 V on block 5. Look between the last 230 V and the first 0 V.

Lessons

A guide beside the canvas

Each step says what to do and checks it: the wire’s colour, the meter’s reading, the answer to a question.

  1. A reading step
    A lesson step: probes on the lamp’s live and neutral, the meter reads about 230 V, then press Check.
  2. Meet the programmer
    Foundation’s parts unit: the dual channel programmer on the canvas, with the lesson explaining each channel.
  3. The colour check
    Wire a connection in the wrong colour and the lesson says so before you move on.
  4. A unit check
    A unit check question, timed and scored: which block carries the room thermostat’s call for heat?
  5. Reading a maker’s terminal map
    Intermediate: reading the terminal map of a programmer based on the Honeywell ST9400C before you wire it.

Call-outs

The job card, in the customer’s words

Fault Vault jobs and Random Fault start from what the customer says. The card never says what is wrong.

  1. Call-out: no heating
    The job card for a no-heating call-out, in the customer’s words. Switch on, confirm it, then pick up the meter.
  2. Call-out: the boiler won’t fire
    A boiler that never lights: the customer’s words on the card, and the method one button away.
  3. Call-out: hot water too hot
    Hot water scalding: the card gives the complaint, never the cause.
  4. Random Fault, Hard
    Random Fault on Hard, on a Y-Plan: the card warns there may be more than one fault on this system.

Testing

The meter, the tester and the proving unit

Volts, ohms and continuity at the terminals, and safe isolation step by step.

  1. Volts at the valve motor
    The multimeter on AC volts across a zone valve’s motor while the heating calls: 229.9 V.
  2. Ohms on the same motor
    Switched off and isolated, the same valve motor measured on resistance: 2.40 kΩ.
  3. Earth continuity
    An earth continuity check with the meter on ohms, the system isolated.
  4. Safe isolation, step 1
    Safe isolation, step 1: prove the two-pole tester on the proving unit before you trust it.
  5. NO EARTH
    Leave a part’s earth unconnected and the simulator marks it NO EARTH.

Parts

Open the lid, read the Manual

Every part has its terminals and a Manual page that says what each one does.

  1. The wiring centre’s Manual
    Every part has a Manual page. The wiring centre’s says a block joins only the wires landed on it.
  2. Inside a 2-port valve
    The 2-port valve’s Manual: the motor, gears, spring and end switch, and what each terminal does.
  3. The pump’s terminal box
    Open a part’s lid and its terminals show: here the pump’s terminal box, live, neutral and earth, ready to wire.
  4. The dual channel programmer
    DrawWarm’s own dual channel programmer, its terminals along the bottom.
  5. The underfloor manifold
    The underfloor heating manifold set, placed on the canvas with its terminals.

The record

A record of practice

The record is signed line by line. The sample certificates carry the name Your Name.

  1. The learner’s record
    The learner’s record, kept on the device and signed line by line: lessons, practicals and hints, unit by unit.
  2. Certificate of completion: Foundation
    A sample Foundation certificate of completion (simulator), made out to Your Name. It records practice in the simulator.
  3. Certificate of completion: Intermediate
    The Intermediate certificate of completion in its stage’s colour, for the sample name Your Name.
  4. A tutor’s task
    A tutor’s task: the customer’s words and the tutor’s own question, with a box for the learner’s answer.

Certificates of completion and credentials are DrawWarm’s own. They record practice and tests in the simulator. They are not a formal (regulated) qualification, and they do not show that anyone is competent to work on a heating system.

The Sandbox

Build it, switch it on, test it

Place any part, wire it your way and run it. Nothing is marked, and nothing can be broken.

  1. Parts placed
    The Sandbox with an S-Plan’s parts placed and unwired, ready for you to wire your way.
  2. A build half done
    A build half done in the Sandbox: nothing is marked, and nothing can be broken.
  3. The exported picture
    File, Export: the circuit as a clean picture with a header, ready to print or share.

Wire it yourself.

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