Flat Immersion Heater Spanner

The Flat Immersion Heater Spanner is a simple flat spanner for removing and refitting the immersion heater element in a hot water cylinder. It is the basic version, suited to uninsulated cylinders where the boss is easy to reach.

When a flat immersion heater spanner is the right tool

Immersion elements fail, scale up or need a new thermostat, so sooner or later the element has to come out. The large nut on the element is far too big for normal spanners. A flat spanner slips over it and gives you leverage. On a cylinder with factory foam lagging round the boss, a box spanner usually reaches better, so check what you have before you start.

• Flat pattern spanner
• For immersion heater elements
• Suits uninsulated hot water cylinders
• Simple, no moving parts

Isolate the electrics first and prove them dead. Then drain the cylinder below the element. Hold the cylinder steady while you undo the element, because a copper cylinder can twist or split if you lean on it hard. Fit a new washer and tighten firmly but not wildly. Refill, check for leaks, and only then restore power. Other spanners are in our spanners section.

Ordering a spanner in Glasgow

Ask at Plumb Parts, 555 South Street, Glasgow G14 0QX. Hours: Mon-Fri 8am-5pm and Sat-Sun 8am-1pm. Or place the order online.

Specification

• Suitable for: Removing and refitting immersion heater elements on cylinders with an exposed boss

Common Questions

Flat or box immersion spanner: what is the difference?

A flat spanner is a simple one piece tool that needs clear access round the boss. A box spanner reaches into lagged or recessed bosses and gives better grip.

Why will my immersion heater not budge?

Scale and age lock them tight. Brace the cylinder so it does not twist, and use steady pressure on the spanner rather than sharp blows.

Do I have to drain the whole cylinder?

Drain it down below the level of the element. A side entry element needs more water out than one fitted in the top.