
Cylinder/Pipe 
Thermostat
Cat. No. TRT044
Operating & Installation Instructions

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 the 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 60ºC and 
65ºC, then left to do its job. This temperature 
is high enough to kill off harmful 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.
®

1. Introduction
TRT products are a cost effective  
comprehensive range of thermostats and 
controllers designed for internal use only.
The TRT044 is cylinderstat, with an easily 
adjustable dial. It is designed to be  
mounted to a domestic hot water  
cylinder using a spring wire, and allows 
the user to economically control the  
temperature of the hot water. It can  
be fitted to all hot water cylinders, or  
alternatively it can be used as a pipestat 
using the alternative wire strap supplied.
The TRT044 can be used to switch  
a circulating pump, boiler, or most  
common motorised zone valves. It can  
also be used for switching domestic 13A 
immersion heaters if required.
TRT044 Cylinder/Pipe Thermostat 
Side View
Cylinder/Pipe  
contact
Rear View of TRT044
2
1
Easy 
set dial
Front View of TRT044
40
°C
50
Clearly 
marked  
dial
60
70
80
Temperature 
adjustment 
knob
Cover 
retaining 
screw
Stylish  
design
Wiring  
terminals
C
Earth 
terminal
Cable 
entry
The electrical supply must be isolated 
before attempting to install the TRT044.
.
Fig. 1a
Fig. 1b
Fig. 1c

Contents
TRT044 cylinder thermostat 
TRT044 instruction leaflet
Spring wire 
Wire strap
2. Siting
The TRT044 is designed to be surface mounted 
onto the domestic hot water cylinder. For 
cylinders with an insulating foam covering, a 
section of foam must be removed so the back 
of the thermostat is in direct contact with the 
metal body of the tank.
The TRT044 should be mounted between a 
quarter and third of the way up from the base 
of the tank in a position that gives good access 
to the dial.
3. Installation
This product should be installed by a qualified 
installer to current installation standards. 
If in any doubt contact the Timeguard Helpline 
020 8450 0515.
Always isolate the mains supply before 
starting work.
Incoming cable should be 1.5mm sq.
Remove cover from unit by unscrewing cover 
retaining screw, and easing off the temperature 
adjusting knob. 
Thread incoming wire though the cable gland.
Allow sufficient excess cable to wire up the 
unit, but not too much to make it difficult to 
close the cover on the unit.
Connect the conductors to the relevant 
terminals, according to the wiring diagram. 
Ensure that the brass washer grips the conductor.
Pull some of the excess cable back through the 
gland and then tighten the gland to trap the 
cable and give good strain relief.
Replace the cover and the adjustment knob.
Adjust the length of the spring wire, and use it 
to strap the TRT044 to the hot water cylinder.
Restore mains to the unit after checking all 
system wiring is complete.
Wiring Diagram
Note: 
Check boiler 
instructions 
before 
connecting.
Terminals C and 2 make on temperature rise. 
Terminals C and 1 make on temperature fall.
Fig. 2
TRT044 
Cylinderstat
C12
4. Operation
Use adjuster dial to set desired temperature.
For vulnerable people it may be advisable to 
reduce the setting to as low as 50ºC bearing in 
mind the outlet water temperature will be 
somewhat higher than this due to the 
temperature stratification in the tank.
To clean use a clean dry cloth only. Do not use 
any liquid cleaners.
5. Specifications
Current rating:  16 (4) A
Voltage:  230V, 50HZ
Switch type:  Single pole, double throw 
 (SPDT) 
Operating 
temperature range: 0°C to 55°C
Set temperature 
range:  40°C to 80°C
Complies with:  BS EN 60730
Conforms to 
directives:  Conforms to 
  latest directives

For assistance with the product please contact:-
HELPLINE
020 8450 0515
or email helpline@timeguard.com
3 Year Guarantee
In the unlikely event of this product becoming 
faulty due to defective material or manufacture 
within 3 years of the date of purchase, please 
return it to your supplier in the first year with proof 
of purchase and it will be replaced free of charge. 
For years 2 and 3 or any difficulty in the first year 
telephone the helpline on
Note: a proof of purchase is required
in all cases. For all eligible replacements (where agreed by
Timeguard Ltd) the customer is responsible for all shipping/
postage charges for sending replacements outside the UK. 
All shipping costs are to be paid in advance before 
a replacement is sent.
For a product brochure please contact:
Timeguard Ltd. Victory Park, 400 Edgware Road,
London NW2 6ND Tel: 020 8452 1112
or email csc@timeguard.com
A       Group company
67-058-330 (issue 2)
 020 8450 0515.