Wiring A Heatmiser IQ+ Controller To An ERP Compliant Suspended Heater
Wiring a Heatmiser IQ+ Controller – Updated 27th May 2018
What Is ErP And Lot 21 And What Is An ERP Compliant Heater?
“The Energy Related Product Directive” (ErP For Short).
ErP Directive (2009/125/EC) is a European Council Regulation that implements a series of measures to reduce greenhouse gas emissions. Lot 21 of the Directive implements changes to warm air heaters.
Lot 21 has three different phase in dates which force increases in seasonal efficiency and the lowering of Nox emissions contained within the flue gasses.
How Does This Affect Wiring A Heatmiser IQ+ with a new Warm Air Heater?
In simple terms, it means we need more wires.
For many years, the gas burner control system has simply been an on / off control. It turns on when heat is demanded and turns off when not required.
Under ErP, when heating a space for occupancy comfort, on / off burners and controls can no longer contribute towards the required seasonal efficiencies.
The Heating Industry has responded and Hi / Lo burner controls is now the standard basic method of control supplied from the factory. Fully modulating is still preferable over Hi Lo.
Hi / Lo control is not new, its been available for many years but due to the increased costs of a Hi / Lo capable burner, most end users were choosing the cheaper On / Off options.
To enable use of Hi / Lo control, we need to use an additional relay in the Heatmiser IQ+ and program the controller to support Hi / Lo operation.
As the space temperature begins to rise, when it reaches the Hi / Lo differential setting inside the controller, a relay is opened and the heater’s burner is instructed to reduce its firing rate.
This lower heat input into the space is often enough to reach and maintain set point. Overshoot of set point is generally avoided, less heat energy is used and as a result, less combustion gases are introduced to the atmosphere.
When starting up the heater, we need to instruct it to turn on in Hi Fire mode, then allow it to drop back to Lo. As always we can easily achieve this with the IQ+.
Wiring A Heatmiser IQ+
Click on the image to view a large PDF version.
Consider the wiring overview above.
When wiring a Heatmiser IQ+, two switch fused spurs are used to satisfy the requirements of BS:7671.
The first spur provides power to the heater and also provides a low level point of isolation / mechanical lock off. As the second spur is fed from the first this gives one point of isolation. If the heater is isolated, so are the controls.
The second spur provides protection to the IQ+ Controller as it requires much less current than the actual heater. Fuse the IQ+ at 5A and the heater either 5A, 10A or 13A depending on current draw.
Select a suitably sized cable to allow for current and voltage drop. Generally a 1.5mm cable is suitable for most smaller suspended heaters, but you may need a 2.5mm in some cases.
Fix the spurs to the wall and connect using a 20mm conduit coupler and two bushes. A Coupler and bushes can be used to fix the Controls spur to the IQ+. Take care marking the IQ+ Controller plate and hold it in place when marking. The alignment is tight to get the hole just right.
When wiring a Heatmiser IQ+, ensure all electrical supplies are turned off and safely isolated with a lock off kit if required. Always make sure the supply is turned off using an approved voltage indicator.
The customers supply should be fed into the Heater spur and terminated to the IN terminals. Provide a Live, Neutral and Earth. Ensure a back box bond is fitted to the spur front.
If using NYYJ cable, stuffing glands can be used to terminate the cable neatly at both ends. SY type cable must not be used for fixed electrical installation. If using SWA or other type of wiring system, ensure that the armour is earthed correctly at both ends. Also make sure the correct type of gland is used for the cable type.
Wire the heater supply cable to the “OUT” or “LOAD” terminals in the heater spur. At the same time route a separate Live, Neutral and Earth from the SAME terminals, to the next spur. Singles can be used here.
In the second spur, wire up the Live, Neutral and Earth (from Heater Spur) into the IN terminals.
Wire from the “OUT” or “LOAD” terminals directly into the Heatmiser IQ+ PCB.
A 7-Core control cable is taken from the top of the second spur and taken up to the heater. Ensure the use of correct terminations as previously discussed. Again, we suggest the use of NYYJ cable.
A length of 2” cable tray fixes the wiring into position extremely neatly and can easily be mounted right up to the heater.
Cut the 7-Core cable a little longer and strip back to the gland. Feed into the spur and route through the bush and coupler, then into the IQ+ controller.
Now would be a good time to take an R1+R2 reading for each of the cables and carry out an insulation test. These can be recorded on the installation certificate and will satisfy dead testing. Take the incoming connections out of the IQ+ before testing. Following dead testing, we can continue wiring a Heatmiser IQ+.
We need to install a few links inside the IQ+ Controller to make things work.
Daisy chain from the Neutral incoming connection, and take this to the N terminal of the “Lock Out Relay” terminals, then feed to the C (Common) terminal of the “Lock Out Reset Relay”. Keep the stripped insulation short and two 1.5mm wires will easily go into the terminals neatly.
These two Neutral jumpers allow the lock out indicator and reset circuitry to work. Lock out reset is normally done with a switched Neutral, so be careful you get this right.
Next in a similar way, daisy chain from the Live incoming connection into relay 1 (Fan) then relay 2 (Lo Fire).
This provides a live feed to the relays so when they operate, a control signal is generated.
Wire earth of the 7-Core inside the spur, there are two connection points and sufficient room to install neatly.
Following the wiring diagram:-
- Cable 1 to the Fan relay
- Cable 2 to the Lo-Fire relay
- Cables 3 & 4 to the Hi-Fire relay
- Cable 5 to the Lockout indicator
- 6 to the Lockout Reset
Check over all the connections carefully and note they may not follow number order.
Close off all the spurs and replace the cover of the IQ+, ensure the ribbon cable is pushed home both ends. This completes wiring a Heatmiser IQ+ controller.
At the heater, terminate both cables off neatly and appropriately.
Connect the L, N and E conductors from the 3-Core cable to the incoming mains terminal block.
Join the E conductor from the 7-Core cable into the main Earth terminal in the heater, alongside the supply E.
Using the chart above, terminate the remaining six cores to the heaters wiring terminal strip.
- Cable 1 provides a manual fan signal, generally called FAN or SUMMER
- Cable 2 provides the signal for heat, generally called HEAT ON or CALL FOR HEAT
- Cable 3 & 4 provide the Hi Heat circuit, generally called HIGH or Hi Fire
- Cable 5 provides a signal to the IQ+ if the heater enters lock out.
- Cable 6 provides a signal to rest the heater, following lock out.
Check all the cables are tight and routed neatly through the heater by giving a gentle “tug test”.
Now would be an ideal time to take relevant Earth Loop readings (Zs) for the installation certificate.
Once you are satisfied that the electrical installation is completed, we need to make some modifications to the IQ+ controller.
Wiring A Heatmiser IQ+ Controller Programming
Turn on the power and allow the controller to boot up.
Lets make some changes to the configuration of the controller first.
Enter Engineer Configuration Menu
Press the [PROG] button, enter the Engineer password “6 3 4 3” followed by the [ENTER] key.
Turn On Optimisation
Lets turn on the Optimisation feature by pressing button  on the keypad.
Remember, when you set up the times later on we will be entering “Opening Times” as the controller handles the actual on / off times on your behalf.
Optimisation allows the heater to turn on a little earlier or later, depending on how cold the room is. During the winter months the heater comes on a little earlier. As things warm up, it comes on a little later.
Press  to enable Optimisation mode and press [ENTER].
Next we need to enter the rate of change figure. Leave this as 20. This figure is the amount of time it takes to heat the building by 1.0 Degree. 20 Minutes is a good starting point. As the controller is self learning, it will adjust this figure automatically. Press [ENTER] after making changes.
Next set the maximum number of hours the heater can come on, before occupancy time. Generally a figure of 2 Hours is sufficient. In some extreme cases increase this to 3 hours.
Press the [ENTER] key and you should drop back to the main engineering menu.
Setup Controller As Hi / Lo Configuration
Next, press  to enter the SETUP menu, then press  to enter CONFIG.
Press  to select Hi / Lo operation and press [ENTER] to move on.
Press  to enable HIGH FLAME BOOST and press [ENTER] to move on.
High Flame Boost closes both the “Hi” and “Lo” relays at start up. After 60 seconds, the controller checks to see if both relays are required. If the temperature is within the differential band the “Hi” relay will then turn off.
Enter the Hi / Lo Differential. If you set this at 4 Degrees and say the daytime temperature was set at 21 Degrees. As the room temperature reaches 18 Degrees, the heater would drop to Lo fire and continue to operate until it reaches 21 Degrees. 4 Degrees is a good starting point for this value.
When the value is input, press the [ENTER] button again.
Press  for Double Ignition to disable then [ENTER].
Do the same  and disable the proving switch, then hit [ENTER].
Next you can set a “User Temperature Limit”. If the controller is programmed with a day time temperature of 21 Degrees, entering 02.0 [ENTER] into this box would allow staff to increase the room temperature to 23 Degrees.
When you drop back to the menu, press the [RUN] button until you drop back out of the menus. The screen will read “Adjusting Setup”.
The user settings can now be set as required for the heater.
When you adjust the on and off times of the controller, remember to enter the opening time rather than the heater on time. The controller will automatically bring on the heating early as we set up Optimisation.
You can download the “IQ+ Quick Start Guide”, together will the full manual below in PDF format.
The “Quick Start Guide” explains most of the controllers functions on one sheet.
If you need any further help wiring a Heatmiser IQ+ controller, or wish to buy any Heatmiser products, please contact us or click here to visit Heatmiser products in our store.
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