SEALED HEATING SYSTEMS

Sealed systems are the most commonly used form of central heating in Europe. Easy to install and alleviate the need to fit feed and expansion tanks in a central heating system. Air and water are separated by a flexible diaphragm. When the system is cold the expansion vessel is nearly full of air or nitrogen, when hot, the water expelled from the system by expansion enters the vessel and compresses the air or nitrogen.

Expansion Vessels

Sizes up to and including 24 litres may be wall mounted using the Mounting Bracket shown below. The 35 and 50 litre sizes have fitted feet. Not for use with potable water. Kitemarked to BS 4814.
TECHNICAL SPECIFICATION: Maximum working pressure 3 bar. Maximum system temperature 99ºC. Thread 3/4" BSP male.
Part No.CapacityDiameterHeight Unit PriceQty
11350
8 litre
228 mm
295 mm
  £25.08
11351
12 litre
98 mm
260 mm
  £27.42
11352
18 litre
298 mm
365 mm
  £28.22
11636
24 litre
328 mm
405 mm
  £31.34
11637
35 litre
380 mm
402 mm
  £56.41
11638
50 litre
380 mm
537 mm
  £78.36

Expansion Vessel Mounting Bracket

Suitable for expansion vessels up to 25 litres. Vessels larger than this should be floor mounted.
Part No.DescriptionUnit PriceQty
11353 Mounting bracket £3.96

Adjustable Hydrostat

The pipe mounted hydrostat (water pressure switch) protects sealed heating system components from operating when the system pressure drops below an adjustable pre-set level. Features a snap action SPDT microswitch assembly. Complies with BS EN 60947-4-1: 2010.
SPECIFICATION:
Connection : 1⁄4" BSP female.
Adj. operating pressure range : 0.15 bar to 1 bar.
Fixed differential pressure : 0.1 bar.
Max. pressure : 10 bar.
Max. fluid temperature : 120°C.
Ambient temperature : -35°C to 60°C.
Microswitch contact rating : 0.2 A.
Protection rating : IP40.
Weight : 0.47 kg.
Dimensions : H 115 mm x W 88 mm x D 49 mm.
Part No.DescriptionUnit PriceQty
20976 B11AN Hydrostat pressure switch £61.60

Pressure Reducing Valves

Suitable for use with combination boilers. Internal cartridge and filter can be serviced in situ.
Maximum inlet pressure 16 bar.
Preset 3 bar. Adjustable 1-6 bar.
Part No.DescriptionUnit PriceQty
11342 1/2" BSP F x F, with gauge 1-9 £31.74
  10+ £28.56  
11343 3/4" BSP F x F, with gauge 1-9 £37.52
  10+ £33.77  
11344 15 mm with gauge 1-9 £29.81
  10+ £26.83  
11345 22 mm with gauge1-9 £31.63
  10+ £28.47  

Water Hammer Arrester

Mechanical, maintenance free device to prevent water hammer in plumbing systems. Fit as close to a single problem tap or valve as possible.
Brass body with polymer piston, steel spring and EPDM seals.

SPECIFICATION :
Max. working pressure : 10 bar.
Operating start pressure : 3 bar.
Max. water hammer pressure : 50 bar.
Max. water temperature : 90°C.


Dimensions :
Body height (excluding thread) : 74 mm.
Max. diameter : 52 mm.
Weight : 0.5 kg.
Part No.DescriptionUnit PriceQty
20923 Water hammer arrester, 1⁄2" BSP £15.84

Shock Arrester

To prevent water hammer. Fit as close to the problem area as possible. Set at 3.0-3.5 bar. Maximum pressure 15 bar.
Vessel capacity = 0.16 litre.
Diameter = 86 mm.
Height =122 mm.
Connection = 1/2" BSPTM

WRAS approved
Part No.DescriptionUnit PriceQty
11355 Shock arrester, 1/2" BSP 1-9 £22.46
  10+ £20.21  

Sealed System Filling Kit

Contains all the essential components required for a sealed system installation.
Contents: filling loop, 3 bar safety relief valve complete with gauge, connecting T-piece and vessel mounting bracket.
Part No.DescriptionUnit PriceQty
11354 Filling kit £47.34

Safety Relief Valves

Diaphragm type safety valves. A necessity for ensuring the safety of sealed systems, to avoid over pressure. Set at 3 bar (44 p.s.i.) pressure, (except 17107 at 2.5 bar).
Part No.DescriptionUnit PriceQty
11346 1/2" BSP Fx 1/2" BSP F, compact head1-9 £5.62
  10+ £5.06  
17107 1⁄2" BSP F x 1⁄2" BSP F, compact head, set at 2.5 bar £6.48

Part No.DescriptionUnit PriceQty
11347 1/2" BSP M x 1/2" BSP F, compact head1-9 £5.39
  10+ £4.85  

Part No.DescriptionUnit PriceQty
12346 1/2" BSP M x 1/2" BSP F, standard head £6.55

Part No.DescriptionUnit PriceQty
11348 1/2" BSP F x 1/2" BSP F with gauge £10.12
11639 3/4" BSP F x 3/4" BSP F with gauge £13.23

Part No.DescriptionUnit PriceQty
11349 1/2" BSP M x 1/2" BSP F with gauge £10.14

NABIC Safety Relief Valves

The NABIC Fig 542 safety relief valve suitable for use on hot water, steam, air, CO2 (to -20°C), ethylene glycol and potable water. Gunmetal construction, with diaphragm protected working parts and PTFE to metal seating. To BS 6759: 1984, WRc approved. All wetted parts are manufactured from dezincification resistant materials, approved by the WRc for use on potable water.

SPECIFICATIONS:
Factory set pressure: 3 bar
Maximum operating temperature: 195°C
Inlet and outlet threads: female to BS 21:1985
Part No.DescriptionUnit PriceQty
19166 1⁄2" £117.98
19167 3⁄4" £135.40
19168 1" £178.98
19169 1.1⁄4" £249.06

Pipe Cowl Fitting, Solder Ring

Pipe cowl fitting designed to fit 15 mm pressure relief valve pipe termination. One solder connection only. Manufactured to EN 1254: 1998 and complies with all current legislation.
Length : 40 mm. Cowl dia. : 28 mm.
Part No.DescriptionUnit PriceQty
20010 15 mm solder ring fitting pipe cowl £3.83

Pressure Relief Outlet Terminal

The 'Pro-Term' has been designed to be fitted easily from inside the building, reducing fitting time; for all pressurized domestic heating systems. Manufactured to BS EN 1254: 1998 and complies with all current legislation. 3 part construction, comprising Pro-Term, stabilising flange and pipe insert.

Pro-Term standard (Type 1) -
designed for walls up to 12" thick 'Standard construction'.
Pro-Term non-standard (Type 2) -
designed for walls up to 39" thick 'Tenements and Sandstone construction'.

Part No.DescriptionUnit PriceQty
18553 Pro-Term Type 1 £17.22
18554 Pro-Term Type 2 £21.80

Straight Tundish

Corrosion resistant, acetal co-polymer straight through tundish with 15 mm inlet and 22 mm outlet compression end fittings to BS EN 1254-2: 1997. Tundish provides Type AA air gap (20 mm minimum air break) and is suitable for sealed or unvented systems.

Max. temperature : 95°C.
Overall height : 104 mm.
Part No.DescriptionUnit PriceQty
20924 15 mm x 22 mm compression £4.94

Aluminium Tundishes

For use where an air gap or air break is required in sealed or unvented systems.
Part No.DescriptionUnit PriceQty
12165 1/2" angle aluminium tundish with 3/4" outlet £12.37
12166 3/4" angle aluminium tundish with 3/4" outlet £12.74