Frequently Asked Questions

Fact checked by members of our Engineering and Technical Team.

Below you will find some of the most frequently asked questions about our Immersion Heating Elements and accessories and answers to those queries.

 

My Immersion Heater needs replacing, how do I know what to buy?

Check your existing Immersion Heater for identification marks (kW rating, volts, item number, IP rating). You can then search our full immersion heater range for the matching product, or read our step-by-step replacement guide.

 

How do I measure the BSP Thread Size of my Immersion Heater?

All domestic Immersion Heaters have a BSP thread size on the brass boss. The actual measurement across the diameter of this boss is 0.25 inches larger than the stated BSP thread size.

Using a vernier caliper, measure the thread of the Immersion Heater, this will be the ribbed section connected to the cap (the brass boss), where the heating element connects.

Once you have measured the thread, browse heaters by size: 1 3/4" BSP, 2" BSP or 2 1/4" BSP. Use the table below to select the correct BSP size:

 

I cannot find the product code for my Immersion Heater; what information do I need to purchase the correct replacement?

You'll need the length, power rating in watts, BSP thread size, and whether your system is vented or unvented. Our step-by-step replacement guide shows exactly where to measure. 

 

How do I know the size of the thread on my Immersion Heater brass boss?

For most Immersion Heaters the BSP thread size will be the last letter on the product code. If you are still unsure if you have the right thread size, you can measure the BSP thread size using our guide which you can find under How do I measure the BSP Thread Size of my Immersion Heater? here in the FAQ.

 

How do I find out the length of my Immersion Heater?

The only way to be certain of the length of your Immersion Heater is to measure from the underside of the brass boss to the end of the heating element. However, if your Immersion Heater is fitted in the side wall of your hot water cylinder (horizontally) then it will usually have a length of between 11 and 16 inches. If it is fitted to the top of your hot water cylinder (vertically) then it usually has a length of 18 to 36 inches depending on the size of your hot water cylinder.

 

Do we manufacture bespoke products?

Yes, contact our technical team to discuss bespoke commercial or industrial requirements. We offer a wide range of industrial immersion heaters as a starting point. 

We offer a wide range of commercial to heavy industrial products. We can offer vessels, ducts, flanges immersion heaters, control panels, accessories, and many others for a range of uses.

 

How do I know what letter of immersion heater to buy?

Our standard BSP coding: 

A = 2 ¼” - Browse

B = 2” - Browse

C = 1 ¾” - Browse

For more information refer to the “How do I measure the BSP Thread Size of my Immersion Heater?” portion of the FAQ.

 

Not sure what else you need?

See our immersion heater thermostats and controls and installation accessories.