Reliant FVIR GAS WATER HEATER Technical Information download pdf (Page 73)

RESIDENTIAL GAS AND ELECTRIC WATER HEATER

TROUBLESHOOTING and SERVICE HANDBOOK

RELIANCE Water Heater Company Technical Training Department

Available air for combustion is essential to a heater. Properly vented heaters and installation conditions

play a huge part in the operation of the heater because without enough air, the heater cannot operate

properly and will shut down. The drafting characteristics of the heater depend upon the heat of the pilot,

main flame and tank temperature to generate draft. WARNING, hotter water temperatures can lead to

scalding. Safety always comes first

. Keeping this in mind, an increase of tank temperature 10° F may help

or even solve the problem. A simple mixing valve installed in the hot water outlet of the heater, will allow

much hotter tank temperatures while providing a worry free solution to scalding.

In conclusion, remember that a heater that is not properly installed will not operate properly. Proper

maintenance and cleaning of the heater and the surrounding area can play a major role as well. For

more information on the operation of you heater you can call 800-365-4054 for technical assistance or

visit the technical bulletin section under the technical literature section of our web site at

www.reliancewaterheaters.com

. There you will find information on everything from water conditions to

noises encountered in your water heater. With proper installation your RELIANCE

water heater will give

you many years of worry free hot water.

Decompression is the third reason that the pilot flame will fail. Decompression happens when the air

pressure inside the structure where the water heater is located, drops below the outside air pressure. If

air can not enter the structure as fast as it is being used then the building will go “negative.” If the room

pressure is negative, then the air pressure outside will push down the vent to equalize the pressure. The

effect is much like “capping”, the combustion products from the pilot stall in the heater flue pipe, and the

pilot runs out of oxygen because there is no draft (upward air movement) to replace the oxygen.

Reasons for a room or building to go negative are a closed room (no makeup air vents) without much, or

no foot traffic, a room that is too small to support the needs of the heater, an attic or kitchen fan that

exhaust air out of the structure without bringing in its own makeup air, or combustion air shared by two or

more gas burning appliances.

If it is a garage installation then try this as a test. Place a small 2” x 4” block of wood under each end of

the garage door (or if the heater is in a utility closet, try opening a window). This will leave a gap for air,

equalizing the pressure and the outage problems may go away. Then simple vents can be placed in the

garage door or exterior wall to help with ventilation. Most homes have no air conditioning ducts in the

garage (to meet energy ratings) supplying air in the garage; which would normally be a source of

combustion air.

Attic installations can be exceedingly hostile. The Constant high temperatures and little to no traffic along

with poor ventilation take there toll. Attic design and materials are very important to good attic ventilation

necessities heater operation. Soffit vents are usually blocked during the construction of the home when

the insulation is blown into the attic. The insulation should not cover the soffits. If the soffits are covered,

then a leaf blower can be used from the outside to blow into the vent. This comes with a warning that all

gas appliances must be turned off and any valuables need to be covered prior to clearing the vents. The

insulation dust can take several hours to settle. Vents, and vent placement, are very important as well.

Ridge vents work the best and can cool the attic by up to 35 degrees F in the summer by cooling the

underside of the roof deck as it is heated by the sun. There are also fewer pockets of dead air with the

roof vents. Attics with no venting devices have no air flow in them except the heated air escaping from

the soffits due to expansion, which leads to insufficient air. One way to determine if there is enough

available air in the attic is to stand in the attic with the door closed and shut off the attic light during

daytime hours (10 a.m. to 4 p.m.)

If no light can be seen from the soffit areas, then chances are that the heater will never have the required

air to support combustion. (See Figure 3)

A lack of combustion air will cause the main burner to have an unstable yellow flame pattern in the

combustion chamber. As the flame “looks” for oxygen, it will change its color and flame pattern and

flatten out in an effort to find an oxygen supply. This will increase the temperature in the bottom of the

combustion chamber and cause the heater to shutdown.

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Reliant FVIR GAS WATER HEATER Technical Information Page 73

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