Piezoelectrico Caldera Compatible con Roca Rs20 R122050410A

Troubleshooting a hot water boiler - repairing a gas boiler

Gas boiler
?A boiler is an appliance that is used to heat water with a hydraulic heating system. The hot water is distributed throughout the house in pipes and radiates heat in the rooms either with steel radiators (in newer homes) or cast iron radiators (in older homes) or with convection heaters in the floor (newer homes). Once the radiator or convection heater is heated with the hot water, the water returns to the boiler to be reheated and the water circulation circuit continues. In addition to radiators, the boiler is also used with radiant floor heating systems.

These boilers can use fuel or natural gas or propane (gas) or can burn fuel oil (oil). Fuel oil boilers require more maintenance than their gas counterparts and require regular attention to the blower and oil filter.

Boiler components
?The boiler is more complex than forced air heating in that it has more parts, valves and controls. However, gas boilers are quite reliable and most problems, when they occur, are normally related to the expansion tank or water circulator pumps.

Let's take a look at the main components of the boiler for a forced water (hydraulic) system:

Hot water supply side:

Aquastat. The thermostat that regulates the temperature of the boiler

Gas valve and burners - combustion assembly that heats the water chamber

Combined pressure/temperature indicator (tridicator) - monitors water temperature and pressure

Water supply valve - controls the flow of water to the boiler

Pressure reduction valve - automatically maintains the correct water pressure at around 12-15 psi

Air vent - automatically removes unwanted air from the hydraulic system

Expansion tank - critical component that allows water to expand as it heats. There are two types of expansion tanks, the horizontal steel expansion tank, of an older and larger style, and the newer smaller diaphragm-style expansion tank.

Flow control valve - regulates the flow of hot water to the system

Pressure relief valve - relieves high water pressure
Hot water return side:

Circulator - electric pump that circulates water through the system

Drain valve - valve that opens to allow draining of the boiler.

PROBLEM: The boiler is not producing heat

PROBLEM: The boiler is not producing heat

Possible causes


The boiler has no power
Water level is low
Pilot failure or electric burner ignition failure
Thermostat failure

Possible repairs

A circuit breaker or fuse controlling the boiler is tripped or blown. Reset the tripped circuit breaker. Replace the blown fuse.
Keep the water level at half full. The boiler's automatic filling system using the pressure relief valve should maintain the correct water level by maintaining pressure levels of 12 to 15 p