General Spares



As well as manufacturing goods, GMS are also able to supply spare and replacement items for your systems such as immersion heaters, gaskets, thermostats, valves, pumps as well as tube bundles and headers.

This leaflet details a variety of spares that we offer, however if you cannot find what you are looking for, please do not hesitate to contact us to discuss your enquiry, we may be able to help you or point you in the right direction.
Immersion Heaters

GMS use electric immersion heaters as an alternative heating source as it requires low installation, maintenance and has low off-peak costs. It can also be a cost effective back-up for other heat sources during periods of low demand and shut-down of the main primary heating source. Electric Immersion Heaters are used as the main source of heat in our Electric Storage Calorifiers

GMS can provide a range of immersion heaters to suit your requirements from 1kW to 250kW power supply in a range of screwed or flanged connections (dependent on Kilowatt rating).

Take a look at our full
immersion heater range by clicking here.
Tube Bundles

U-Tube batteries are the most common method of heat exchanger for use with calorifiers. The battery consists of a number of ‘ U-tubes’ expanded into a tube plate. The tubes and tube plate can be manufactured in a variety of materials to suit the shell material and application.

GMS can design U-tube Bundles based on kilowatt rating, primary temperatures available and the secondary temperatures required. Tube bundles can be designed and manufactured for new installations or can be designed as replacement items suitable for existing units.

Replacement Gaskets

Replacement gaskets can be provided in NBR, EPDM or NOVUS materials. Gaskets can be provided for headers, flanges, and inspection openings. If the replacement gasket is for a GMS unit all the information that we require is the original contract reference. If the gasket is for a ‘non-GMS’ unit we will require a template or details regarding the PCD, overall diameter, thickness required etc. Our sales department will be more than happy to help you with your enquiry.

Unvented Kit

We quote all of our unvented cylinders with an unvented kit, however if you forgot to order one or just need a couple of spares GMS can provide a quotation for the correct unvented kit that you require. Including;

  • Expansion Vessel

  • Expansion Vessel Accessories

  • Temperature & Pressure Releif Valves

  • Anti Vacuum Valves

GMS are also able to provide you with a full range of valves and accessories that you may require for water systems such as; air vents, check valves, PRV valves, strainers, steam traps, bursting discs, solenoid valves, control valves and many more.


The GMS dial thermometer is a standard dial thermometer for use with water applications and comes complete with pocket (other thermometers can be quoted on request). Specification as below;


Mounting: Bottom or Back entry

Temperature Range: 0˚C to 120˚C

Maximum Pressure: 16 BarG

Pocket: 100mm ½” BSP Solid One Piece Brass

Dial: 100mm Diameter, Dual Scale ˚C & ˚F


GMS stock a variety of own brand pressure and altitherm gauges.

GMS Altitherm Gauge – displays both the pressure and temperature (0-4 BarG, 0-120˚C) bottom entry

GMS Pressure Gauge – bottom/back  entry, 100mm/63mm Diameter  Dial, 1/4” / 3/8” BSP Connection, 0-7 BarG or 0-14 BarG


We can also offer alternatives if you require a different specification

Expansion Vessels

Expansion vessels are commonly used to protect closed water heating systems and domestic hot water heating systems from being exposed to high pressure. Expansion vessels work by being part filled with air, this then protects the system by cushioning any shock which is caused by water hammer and also absorbing any excessive water pressure which may have been caused by thermal expansion.

GMS supply two types of expansion vessel


·         Heating Expansion Vessel

·         Potable-Water Expansion Vessel

Take a look at our full range of expansion vessels by clicking here.

Please contact our sales department for more information about any of our spares listed above including price and availability.

If you require something that is not mentioned above please contact our sales team as we may be able to help you out or point you in the right direction if we do not supply it ourselves.

This page includes...

    Immersion Heaters

    Tube Bundles

    Replacement Gaskets

    Unvented Kit & Valves



    Expansion Vessels 

Information Pages

     Expansion Vessels

     Immersion Heaters 

Literature Available

    Complete Spares Brochure

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