Heated backflow covers and enclosures are often necessary in cases where an irrigation backflow valve or drinking water rpz is going to be left outdoors during cold winters in areas of the united states experiencing below freezing weather for extended periods of time.
While most areas require only backflow insulation for freeze protection, certain installations require an additional heat source to keep water from freezing within the valve gate, expanding as it freezes and causing serious damage to the sensitive o-rings, gaskets and valve parts within. Once a backflow valve has been damaged it will require testing, repair or replacement, all of which is expensive and best if avoided.
Many municipalities in cold areas require heated backflow covers and enclosures to be installed to protect city water systems. If a backflow is damaged by freezing water the damage may cause obvious leaking, or most of the damage can be internal. Even if the unit appears to be functioning properly, it may allow water to flow backwards through it in a low pressure scenario, and this can cause contamination.
Types Of Heated Backflow Covers And Enclosures
Depending on how cold it gets, wind velocity and valve type there are different ways to use a heated backflow cover or enclosure. In some instances a light bulb placed under the backflow enclosure can radiate enough heat to help prevent freeze or frost damage. This technique is a bit of a shot in the dark, however, since one really doesn't know how many watts the bulb needs to be and how well insulated the enclosure needs to be in order to retain the limited amount of heat radiating from the bulb.
And there's always the chance that light bulbs will burn out and cease to produce heat which could result in pipes freezing or valve gate damage. Too much wattage may pose a problem if the bulb comes in contact with any insulation material or plastic inside heated backflow enclosures & covers, causing the material to melt or possibly even burn and creating a fire.
A much more dependable and easy to use method for creating heated backflow covers and enclosures for freeze protection is to use electric heat tape. Wrapping the heat tape around the backflow piping and the valve body itself will help protect the entire unit from the ground up. This process heats the actual metal to prevent water inside from freezing, expanding and causing damage to the pipes or valve gate. Heat tape works well on backlow devices manufactured by Febco, Watts, Wilkins, Zurn, Conbraco and other popular brands of residential and commercial backflow prevention valves.
The DekoRRa Model 301 and 302 boxes are both available as ASSE Class 1 heated backflow covers and enclosures which include easy to use heating tape, an r-13 insulation pouch, and the hard resin enclosure. DekoRRa designed this system to work efficiently in order to retain the most heat. The heat tape is wrapped around the valve and piping then plugged in to any 110v outlet. The backflow insulation bag is placed over the entire unit, followed by the locking resin enclosure.
This backflow freeze protection system is ideal because the insulation is right up against the heat source to help retain maximum R-value. And the tightly sealed backflo insulation bag and hard resin enclosure provides excellent protection from the wind, which can be a major culprit for robbing heat from backflow valves and causing them to freeze.