The largest choice of DIY products

What is a Connection Kit for an Electric Water Heater?

Guide written by:
Holly, self-taught DIYer, Cardiff

Holly, self-taught DIYer, Cardiff

22 guides

A connection kit contains the essentials for connecting a water heater to standard cold and hot water intakes. Service valves, a drain tube and connector hoses are essential when installing a storage water heater.

Important features

  • Service valves

What does a water heater connection kit contain?



A connection kit contains the main parts required for connecting a standard storage water heater. The storage tank and the thermostatic mixing valve are often excluded from the kit. It contains the following :

  • Service valves;
  • Drain trap;
  • Drain trap;
  • Drain tube;

The connection kit may contain teflon tape, brass fittings, glue etc.


Service Valves

Service valves are safety devices that protect the hot water tank from overpressurisation generated by heating water. Service valves are angled (elbow) or straight, made of brass or stainless steel, and can be anti-scale, teflon-coated, and with dielectric connectiors in order to protect it from corrosion.


Drain Trap 

The volume of  water heated by an electric resistance heating element increases as it expands.  Because the tank of the storage water heater does not expand, it is necessary to drain it. The drain transports the excess expanded water released by a service valve by routing it to the used water trap.


The drain trap is made of plastic and is connected to the seat of the service valves.  It is connected to the water heater or to a tee connected to an expansion tank to limit water loss, promote energy savings and protect the service valves.


Drain pipe 


The drain pipe is useful for connecting the trap to a wastewater pipe . It is made of plastic and articulated in order to adapt to different configurations.



Connector hose



Connector hoses are flexible and come in 3/4 " (20 x 27 mm) female-female or female-male.



Expansion tank



The water released after expansion represents approximately 3% of the volume of the hot water tank, which is a significant loss over a years time. To compensate for this loss, an expansion tank can be installed between the service valves and the tank . It is sized to the volume corresponding to 3% of the tank and to the temperature set point as water expands when heated. Expansion tanks must be certified for the production of domestic hot water (ECS).



Thermostatic mixer



It is a anti-scale device mounted at the hot water outlet of the storange tank. More often than not, keeps the temperature of the water between 30 to 50 ° C  and is required in new installation. 

Did you find this guide helpful? Yes
0 upvotes
Guide written by:

Holly, self-taught DIYer, Cardiff 22 guides écrits

Holly, self-taught DIYer, Cardiff
I have to admit that my educational background has little to do with my current passion: all things DIY. Studying management may have given me an ability to keep projects on track, but it's not much use when faced with the prospect of giving an old house a fresh new look.

My passion for DIY all started 5 years ago, when my husband and I bought our very first house. We were so proud...and then we saw how much work needed to be done! Since I basically started with no knowledge of home renovations, I had to learn as I went along, working on projects both great and small. My husband helped me at first, but soon, I was showing him what to do!

Where we live, the rain makes gardens grow wild, so I've become somewhat of an expert on gardening tools. My friends and family all come to me when they need DIY and gardening advice. Now I want to share that knowledge - with you!

The products related to this guide