Radiator Not Getting Hot

Common Water Distribution Problems and Solutions

  1. No heat
  2. No heat, motor housing hot
  3. Gurgling sound in pipes or radiator
  4. Burner does not turn of
  5. Heat uneven throughout the house
  6. Radiator is cold, hammering noise in pipes
  7. Not enough heat, convector is lukewarm
  8. Not enough heat, radiators are lukewarm (water pressure is low)
  9. Radiators are lukewarm (water pressure exceeds 30 psi soon after burner turns on and safety valve discharges)
  10. Radiators above boiler are lukewarm, others are cold
  11. Circulator motor noisy
  12. System sounds like chain being dragged through it
  13. Water spills from safety valve Discharge pipe
  14. Circulator pump leaks
  15. Inlet valve leaks
  16. Bleed valve drips constantly or will not turn

No heat

Possible CauseProcedure
No power to systemReplace fuse or reset breaker
Aquastat faultyTest aquastats and have them replaced if necessary
Air trapped in radiators or convectorsBleed radiator and covectors
If frequent bleeding is required, install automatic bleed valves
Coupler brokenCall for service to have coupler replaced
Circulator pump faultyCall for service
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No heat, motor housing hot

Possible CauseProcedure
Circulator motor burned outCall for service
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Gurgling sound in pipes or radiator

Possible CauseProcedure
Air trapped in radiatiorBleed radiator
If frequent bleeding is required, install automatic bleed valves
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Burner does not turn off

Possible CauseProcedure
Burner aquastat faultyTest aquastat and have it replaced if necessary
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Heat uneven throughout the house

Possible CauseProcedure
Air trapped in radiators or convectorsBleed radiator and covectors
If frequent bleeding is required, install automatic bleed valves
Coupler brokenCall for service to have coupler replaced
Circulator pump faultyCall for service
Pressure reducing valve set too lowCall for service
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Radiator is cold, hammering noise in pipes

Possible CauseProcedure
Sagging floor makes radiator slope, trapping cold water
or air pockets in the radiator
Level sloping radiator with shims, raising the leg below the bleed valve.
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Not enough heat, convector is lukewarm

Possible CauseProcedure
Convector fins dirty or bentVacuum convector fins and straighten them
with broad-nose pliers
Air trapped in convectorBleed convectors
If frequent bleeding is required, install automatic bleed valves
Circulator pump faultyCall for service
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Not enough heat, radiators are lukewarm (water pressure is low)

Possible CauseProcedure
Pressure gauge set too lowCall for service
Pipes leakingTighten pipe joints with a wrench
Call for service
Pressure reducing valve faultyCall for service
Rust deposits in boiler or pipesDrain and refill boiler system, adding rust inhibitor
Circulator pump faultyCall for service
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Radiators are lukewarm (water pressure exceeds 30 psi soon after burner turns on and safety valve discharges)

Possible CauseProcedure
Old-style expansion tank waterlogged or leakingRecharge expansion tank
Call for service if leaking
Diaphragm-type expansion tank waterlogged or leakingReplace expansion tank
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Radiators above are boiler lukewarm, others are cold

Possible CauseProcedure
Pump aquastat faultyTest aquastat and have it replaced if necessary
Circulator pump or motorCall for service
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Circulator motor noisy

Possible CauseProcedure
Motor and pump not properly maintainedPry open port caps and lubricate with not-detergent SAE-30
motor oil
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System sounds like chain being dragged through it

Possible CauseProcedure
Coupler brokenCall for service to have coupler replaced
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Water spills from safety valve Discharge pipe

Possible CauseProcedure
Old-style expansion tank waterlogged or leakingRecharge expansion tank
Call for service if leaking
Diaphragm-type expansion tank waterlogged or leakingReplace expansion tank
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Circulator pump leaks

Possible CauseProcedure
Pump seal or impeller brokenCall for service
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Inlet valve leaks

Possible CauseProcedure
Valve packing deterioratedReplace valve packing
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Bleed valve drips constantly or will not turn

Possible CauseProcedure
Bleed valve faultyReplace valve
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