Easiest Way To Fill your Outdoor Boiler with Water - In House Fill Kit

When your outdoor boiler is low on water, how do you refill it?

Outdoor boilers are open to the atmosphere so water will naturally evaporate over time. 

How Often Do Outdoor Boilers Require Adding Water?
This depends upon the time of year, wind, how hot you keep your boiler, and other factors. I find that my boiler needs water once every 6 weeks. For some it is every 4 weeks, but the average lies somewhere between 4 and 8 weeks. 

If you can go an entire season without adding water, check your water level - it may be dangerously low. Very rarely can an outdoor boiler operate an entire season without adding water and keep the boiler safe.

What if I Operate The Boiler Low on Water?
Some outdoor boilers with sophisticated electronics will just shut off and will not work without water filled to a certain level. If your boiler does not function, check the water level and add water if needed.

The GX Series outdoor boilers have all met the UL Standard 2523 which requires a low-water cutoff. There is a small red dot light that will illuminate on the front of the controller indicating that the water level is low and the boiler has been disabled until water is added.

What Is The Easiest Way To Add Water To An Outdoor Boiler?  
Most of our customers already know the answer to this question - you simply open a valve in the basement and watch the boiler until water comes out the vent tube at the top.  This system incorporates a kit we call the "In-House Fill Kit".

The In-House Fill Kit allows you to add water to your boiler by opening a valve that connects the domestic water supply to the boiler loop - IN YOUR BASEMENT! Without this kit, the boiler must be filled using buckets of water you carry to the boiler, or a hose that you have to drain each time so it does not freeze - what a pain that would be!


This system uses a backflow preventer to keep your domestic water supply safe. You would never want outdoor boiler water to backflow back into your domestic water supply and come out your sink or shower. Our system prevents that perfectly. Also, our system meets codes that are required to keep domestic water systems safe.

So all you do is open the valve for a few seconds, and PRESTO! your outdoor boiler is full again.  Remember to bypass any water softeners if you are filling the boiler for the first time.

As always, call us with any questions you may have during our convenient office hours of 9am-8pm M-F.  We are eager to help you save money on your heating bills for decades!