OK, so those pesky water heaters don't always work right.  Often they will suddenly stop making hot water.  What's wrong?

If you read and followed the instructions that came with your appliance, you are probably disappointed with the performance.  The instructions are less than ideal.

Set the water heater controls as follows: Invierno / Verano:  Set to Verano Temperatura del Agua:  Set to Alta Potencia de Flama:  Set to Baja

The first control (if you have it) turns on extra burners for freezing winter weather in the Invierno (winter) setting.

The second control (Temperatura del Agua) actually doesn't control the temperature of the hot water. It controls when the water heater runs, depending on the flow of the water. I want the heater to work with the lowest flow of hot water, so it needs to be turned all the way to alta (high). 

The third control (Potencia de Flama) is the size of the flame.  This is where I control the temperature of the hot water.  I set it all the way low (baja).  If this is too cool, you can turn it up a bit, but if you have to mix cold water with the hot water in the shower for instance, the water heater may cycle off. That is because when you turn on the cold water, the hot water flow is reduced.  It may be reduced enough to shut off the flame.

These heaters do require a minimum water pressure of about 20 PSI to operate. This is to prevent the unit from overheating.  If you are on municipal water, you probably have to have a storage tank and pump since the IDAAN water pressure often falls below 20 PSI.

WHY NOT SWITCH TO ELECTRIC?

It is 3 to 4 times more costly to use electricity to heat the water. A large heater will require 220 volts and a hefty sized dedicated circuit.

Technical Facts:

1 gallon of Propane ~= 4.23 lbs. ~= 91,500 BtuH 1 lbs. of Propane ~= 22,000 BtuH 20 lb. tank of propane holds approx. 4 gallons of propane (~= 366,000 BtuH)

16,600 BtuH is roughly 4.9 kWh of electricity therefore ... 20 lb. LP gas ~= 108 kWh of electricity

20 lb. LP gas costs $4.85 108 kWh of electricity costs $18.36 (The electricity here in Panama costs $0.17/kWh)

Almost 4 times as expensive to use electricity based on cost.

Efficiency factors

http://en.wikipedia.org/wiki/Water_heating

QUOTE electric heaters tend to be slightly more efficient (if one omits the power station losses) with recovery efficiency (how efficiently energy is transferred to the water) reaching about 98%. Gas fired heaters have maximum recovery efficiencies of only about 86% (the remaining heat is lost with the flue gasses). Overall energy factors can be as low as 80% for electric and 50% for gas systems.

However,Since electricity production itself today has efficiency levels ranging from only 15% to slightly over 55% (combined cycle gas turbine), with around 40% typical for thermal power stations, direct ELECTRIC water heating is typically the LEAST energy efficient option. UNQUOTE

Using price and unit efficiency alone, it is still less costly to use gas. Factoring in the least efficient ratings for the water heater: Heat lost due to inadequate insulation add 20% to electric cost ~= $22.03 to produce 366,000 BtuH Heat lost to the flue and radiated heat add 50% to gas cost ~= $7.28 to produce 366,000 BtuH

It is at least 3 times more expensive to use electricity to heat water based on cost and efficiency losses