What are controls?

“What difference do controls make?”; “What are the best types?”

Controls have come a long way in the past ten years and they afford an excellent way to improve comfort conditions and save energy.

Controls have two primary functions:

Deciding when the heating system comes on and goes off. It is a good idea (and a requirement for new installations) to divide the house into zones (eg living areas and bedrooms) and to have separate timeclock control over each zone.

Maintaining a pleasant comfort level in the rooms. The most cost effective way of achieving this is by fitting thermostatic valves to radiators. These valves automatically regulate the radiator heat output to provide a constant temperature in the room.

It’s generally much cheaper and more CO2 friendly for your boiler to provide your hot water needs instead of using an electrical immersion. Most modern boilers can supply heat to the hot water cylinder and the space heating circuit (e.g. radiators) independently. This means that when you need hot water in warmer weather your boiler does this without having to heat the radiators at the same time.

Where possible it is desirable to have independent control over space and water heating. And now, with the Better Energy Homes scheme, you could even get a grant to help cover the cost of upgrading your heating controls

Controls - Horstmann

Horstmann...Together, we're in control!

Control, it's what we're good at and in domestic central heating and hot water installations that means more accurate control of time and temperature all around the system. Sometimes the solution needs to be simple, like a room stat and timer installation or it can be more sophisticated requiring 3 or 4 channel electronic programmers which can independently handle hot water and separate heating zones.

Our latest electronic room thermostats are proven to save up to 10% in energy costs* by increasing the efficiency of the boiler firing regime. Wireless, mains or battery versions of our controls are available across the Horstmann range.

• Thermostats
• Time
• Switches & Programmers
• Programmable
• Thermostats
• Motorised
• Valves
• Electric
• Water Heating Controls
• Boost Controls
• Wireless Products

SystemLex

A pre-configured wiring centre for controlling heating zones.

Just connect power, boilers, thermostats and timers. SystemLex does the rest.

SystemLex is designed for up to: Four zones Two heat sources Auxilliary functions (see below) All connections are numbered for foolproof installation.

Let's look at the SystemLex board in more detail...

	Wiring the zones... Here is zone 1 on the left of the board. Each heating zone is clearly marked.  Terminal for clock Terminal for thermostat (can be combined with the clock) Terminal for zone pump (or motorised valve) LED showing when that zone is supplying heat There is also an LED to show that power is being delivered to the SystemLex. All the LEDs are visible when the lid is in place. This picture shows the mains fuse and also the fuse for the individual zone.
	Power supplies... The power supplies are clearly marked
	Boiler connections... There are two sets of boiler supplies that switch in unison: Permanent Live, Neutral, Earth terminations Independent boiler voltage-free contacts to provide boiler switch-live or external controls link.
	Auxiliary logic switching facility... This set of connections may be used if an auxiliary function is to be performed, such as 'Hot Water Priority' or where an additional boiler, pump or valve is required. There are two sets of 'voltage free' terminals situated at the right hand side of the wiring termination block. These switches have both normally open and normally closed sides. Both switches switch simultaneously when power is presented at any one of the auxilliary inputs. The auxilliary inputs are independent of each other. These terminals exist to cater for the unexpected control dilemmas that regularly occur during heating installation, and will easily solve many otherwise exasperating problems.

SystemZone is a patented distribution manifold for use in zoned heating systems. It contains all the elements for correct system installation.

SystemZone has many unique features: Zone and boiler circuits are all independent of each other Safety is built in Very good hot and cold water separation Automatic neutral point Simple rugged design - no moving parts Simple to design even the largest systems Straightforward installation Efficient continuous air extraction

SystemZone is ideal for simplifying many complex installations. Here are a few examples:

Boiler arrays Here SystemZones are used to collect water from multiple boilers and to distribute it to multiple heating zones. Installation of a boiler array is less expensive than one or two large units with tall chimneys.

Here is a smaller boiler array suitable for a large dwelling or small commercial premises. The boilers in use in an array will work most of the time at their optimum load and therefore will be most efficient. Boilers also act as back-up for each other, allowing for maintenance and repair while keeping the system running as normal.

Integrating renewable energy sources SystemZone is excellent for complex systems with a variety of heat sources and different heat emitters. Here is a typical installation with an air-to-water heat pump, a back-up boiler (gas or oil), solar powered hot water with underfloor heating and radiators. The illustration shows the SystemZone incorporated in the SystemLink Zoning Centre.

Solid fuel combinations SystemZone is ideal for systems where different heat emmitters are combined, such as solid fuel and oil or gas.

The Easy Way of Combining Sealed & Open Vented

Systems

 

A SystemZone Manifold & Plate Heat Exchanger

efficiently connects an Open-Vented Solid Fuel Stove to your Sealed Heating System

 

 

 

 

Benefits

 

• Easy to install

 

• Available in 15kW, 20kW & 30kW, sized specifically for solid fuel

temperatures

 

• Insulated or Non-Insulated options available

 

• Easy to control when used with one of our wiring centers

-HomeZone Controller or SystemLex

 

 

How to link a Sealed Heating System with an Open-Vented Solid Fuel Stove   In this schematic you can see a standard 3-zone system with dual heat sources. The exception being the Plate Heat Exchanger between the Stove and the Systemlink zoning/link-up manifold. It is this heat exchanger that allows the heat to transfer but not the differing pressures of the sealed and open-vented elements of the system.   You should use this simple method to join a sealed system with an open-vented Solid Fuel Stove as long as you can install a continuosly rising pipe through either the cylinder coil and/or a heat leak radiator. The need for the continuosly rising pipe is due to the gravity thermosyphoning cicuit that should be created for the stove. If you cannot get continuosly rising pipe from the stove to either the cylinder coil then you should use the Heat Genie which solves the most difficult of Solid Fuel installations where gravity ciruits are troublesome.

This is a similar setup as above but with a stove that has only 2 pipes at the back for connection to the heating system, in this case you simply tee off from the 2 pipes to create 4 pipes. An injector tee should be used in this scenario.

HomeZone is a fully intuitive heating zone controller with a separate wiring centre to allow for 230 volt functionality.

HomeZone has many benefits for the installer and the user, including: Very simple interface  Dedicated wiring centre Ideal for multiple zones and different heating sources Saves time and cost at installation Easy fault diagnosis

The controller is a stylish modern design that can be sited in living or sleeping areas:

	The HomeZone controller uses an interactive screen with soft keys and direction button that are very intuitive in use. There is a power button and a help button to guide the user as required.
	The HomeZone controller screen is very intuitive for the homeowner. Clear indication of the status of each zone Simple boost and advance functions LEDs showing active zones

	The HomeZone wiring centre
	The wiring centre has connections for: Pump and thermostat for each zone One boiler Auxilliary functions, such as additional heat sources (such as solid fuel), priority hot water, boiler lockout, etc.

	The schematic opposite shows the HomeZone wired to a typical domestic system with three zones and a boiler. This illustration uses pumps, which will be used in conjunction with a SystemZone or a ZoneAlone manifold.
	HomeZone works just as well with systems using motorised valves to control heating zones.

What is a room thermostat?
... an explanation for householders
A room thermostat simply switches the heating system on and off as
necessary. It
works by sensing the air temperature, switching on the
heating when the air temperature falls below the thermostat setting, and
switching it off once this set temperature has been reached.
Turning a room thermostat to a higher setting will not make the r
oom heat up any faster. How
quickly the room heats up depends on the design of the heating system, for example, the size of
boiler and radiators.
Neither does the setting affect how quickly the room cools down. Turning a room thermostat to a
lower setting
will result in the room being controlled at a lower temperature, and saves energy.
The heating system will not work if a time switch or programmer has switched it off.
The way to set and use your room thermostat is to find the lowest temperature setting
that you are
comfortable with, and then leave it alone to do its job. The best way to do this is to set the room
thermostat to a low temperature
–
say 18
o
C
–
and then turn it up by one degree each day until you
are comfortable with the temperature. You wo
n’t have to adjust the thermostat further. Any
adjustment above this setting will waste energy and cost you more money.
If your heating system is a boiler with radiators, there will usually be only one room thermostat to
control the whole house. But you c
an have different temperatures in individual rooms by installing
thermostatic radiator valves (TRVs) on individual radiators. If you don’t have TRVs, you should
choose a temperature that is reasonable for the whole house. If you do have TRVs, you can choos
e a
slightly higher setting to make sure that even the coldest room is comfortable, then prevent any
overheating in other rooms by adjusting the TRVs.
Room thermostats need a free flow of air to sense the temperature, so they must not be covered by
curtai
ns or blocked by furniture. Nearby electric fires, televisions, wall or table lamps may prevent
the thermostat from working properly
What is a cylinder thermostat?
... an explanation for householders
A cylinder thermostat switches on and off the heat
supply from the boiler
to the hot
-
water cylinder. It works by sensing the temperature of the
water inside the cylinder, switching on the water heating when the
temperature falls below the thermostat setting, and switching it off once
this set temperature
has been reached.
Turning a cylinder thermostat to a higher setting will not make the water heat up any faster. How
quickly the water heats up depends on the design of the heating system, for example, the size of
boiler and the heat exchanger inside th
e cylinder.
The water heating will not work if a time switch or programmer has switched it off. And the
cylinder thermostat will not always switch the boiler off, because the boiler sometimes needs to heat
the radiators.
Cylinder thermostats are usually
fitted between one quarter and one third of the way up the
cylinder. The cylinder thermostat will have a temperature scale marked on it, and it should be set at
between 60C and 65C, then left to do its job. This temperature is high enough to kill off harmf
ul
bacteria in the water, but raising the temperature of the stored hot water any higher will result in
wasted energy and increase the risk of scalding.
If you have a boiler control thermostat, it should always be set to a higher temperature than that of
the cylinder thermostat. In most boilers, a single boiler thermostat controls the temperature of water
sent to both the cylinder and radiators, although in some there are two separate boiler thermostats

What is a programmer?
... an explanation for h
ouseholders
Programmers allow you to set ‘On’ and ‘Off’ time periods. Some
models switch the central heating and domestic hot water on and off at
the same time, while others allow the domestic hot water and heating to
come on and go off at different tim
es.
Set the ‘On’ and ‘Off’ time periods to suit your own lifestyle. On some programmers you must also
set whether you want the heating and hot water to run continuously, run under the chosen ‘On’ and
‘Off’ heating periods, or be permanently off.
The tim
e on the programmer must be correct. Some types have to be adjusted in spring and autumn
at the changes between Greenwich Mean Time and British Summer Time.
You may be able to temporarily adjust the heating programme, for example, ‘Override’, ‘Advance’
o
r ‘Boost’. These are explained in the manufacturer’s instructions.
The heating will not work if the room thermostat has switched the heating off. And, if you have a
hot
-
water cylinder, the water heating will not work if the cylinder thermostat detects tha
t the hot
water has reached the correct temperature

What is a programmable room thermostat?
... an explanation for householders
A programmable room thermostat is both a programmer and a room
thermostat. A programmer allows you to set ‘On’ and ‘Of
f’ time periods
to suit your own lifestyle. A room thermostat works by sensing the air
temperature, switching on the heating when the air temperature falls
below the thermostat setting, and switching it off once this set temperature has been reached.
So,
a programmable room thermostat lets you choose what times you want the heating to be on, and
what temperature it should reach while it is on. It will allow you to select different temperatures in
your home at different times of the day (and days of the we
ek) to meet your particular needs.
Turning a programmable room thermostat to a higher setting will not make the room heat up any
faster. How quickly the room heats up depends on the design of the heating system, for example,
the size of boiler and radiat
ors.
Neither does the setting affect how quickly the room cools down. Turning a programmable room
thermostat to a lower setting will result in the room being controlled at a lower temperature, and
saves energy.
The way to set and use your programmable r
oom thermostat is to find the lowest temperature
settings that you are comfortable with at the different times you have chosen, and then leave it
alone to do its job. The best way to do this is to set low temperatures first, say 18
o
C, and then turn
them u
p by one degree each day until you are comfortable with the temperatures. You won’t have to
adjust the thermostat further. Any adjustments above these settings will waste energy and cost you
more money.
If your heating system is a boiler with radiators, t
here will usually be only one programmable room
thermostat to control the whole house. But you can have different temperatures in individual rooms
by installing thermostatic radiator valves (TRVs) on individual radiators. If you don’t have TRVs,
you should
choose a temperature that is reasonable for the whole house. If you do have TRVs, you
can choose a slightly higher setting to make sure that even the coldest room is comfortable, then
prevent any overheating in other rooms by adjusting the TRVs.
The time
on the programmer must be correct. Some types have to be adjusted in spring and autumn
at the changes between Greenwich Mean Time and British Summer Time.
You may be able to temporarily adjust the heating programme, for example, ‘Override’, ‘Advance’
o
r ‘Boost’. These are explained in the manufacturer’s instructions.
Programmable room thermostats need a free flow of air to sense the temperature, so they must not
be covered by curtains or blocked by furniture. Nearby electric fires, televisions, wall or
table lamps
may prevent the thermostat from working properly.



What is a thermostatic radiator valve (TRV)?
... an explanation for householders
TRVs sense the air temperature around them and regulate the flow of
water through the radiator which the
y are fitted to. They do not control
the boiler.
They should be set at a level that gives you the room temperature you want. These settings may
have to be different in each room, and you should set the TRVs to suit each room and then leave
them to do th
eir job.
Turning a TRV to a higher setting will not make the room heat up any faster. How quickly the room
heats up depends on the boiler size and setting, and the radiator size. Turning a TRV to a lower
setting will result in the room being controlled a
t a lower temperature, and saves energy.
TRVs need a free flow of air to sense the temperature, so they must not be covered by curtains or
blocked by furniture.
TRVs cannot turn off the boiler when the whole house is warm. To do that, you will need a roo
m
thermostat as well. The radiator in the room with the room thermostat should not normally have a
TRV, but, if it does, keep the TRV on the maximum setting and adjust the room thermostat as
explained with the instructions