Following Mr Combi's hugely successful one day fault finding course and DVDs, this application will help you use your multimeter effectively. It will show you how to ensure a boiler is safely installed, safe to work on and conforms to BS7671. It can also help you to identify the cause of faults!

The app has four parts: the Electrical Safety Tests, a Multimeter Guide, an Ohm's Law Guide and has a built-in Ohm's Law Calculator.

Electrical Safety Tests
The app will show you how to carry out all of the tests from start to finish to help you make sure the boiler is completely safe. The tests should be completed after an installation (before switching on the appliance) or before carrying out any work on an existing boiler. Each test contains easy to understand images to make it much simpler to follow. Many electrical faults can be identified from the tests and the Fault Isolation page should help you to find the cause.

There are six parts, these are:

• Before Starting
• Earth Continuity Test
• Short Circuit Test
• Resistance to Earth Test
• Polarity Test
• Fault Isolation

We asked someone who had never used a multimeter to use the app and they were able to carry out the tests with ease!

Multimeter Guide
To help you to get a better understanding of how to use your multimeter, this app includes a multimeter guide. It consists of the following parts:

• Multimeter types
• Multimeter settings (those settings needed when working on boilers)
• Know your multimeter (so you will know what to look for on your own multimeter)
• SI Prefixes (to help you understand the multimeter results)

Ohm's Law Guide
If you're a beginner with electrics the Ohm's Law Guide will help to give you a better understanding of the calculations. The first two pages will explain Ohm's and Watt's Laws, page 3 explains how to add together resistances in series and parallel and the last four pages contain every possible formula for conversions between voltage, current, resistance and power.

A complete Ohm's Law reference guide you can take with you - wherever you go!

Ohm's Law Calculator
Our very popular Ohm's Law Calculator is included in this app. It's extremely easy to use; enter two known values, select the units, press the 'Calculate' button and the other two values will be entered instantly!

What's New

Version 2.4

We've updated a couple of the images to make them easier to understand.


Mr Combi Sales Ltd.
1.7 MB
Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.
Age Rating
Rated 4+
© Mr Combi Training Ltd.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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