Heating Boiler Diagnostic FAQs

Q&A on Diagnosing Problems at Oil or Gas Fired Hot Water Heating Boilers

Gas Fired Boiler Soot FAQs

Soot Stains at gas boiler pilot light control or burner!

Smoke stains and soot are being left on the bottom of the unit where you open to light the pilot on my gas boiler.

I assume that means it needs cleaning inside.

Is this something a homeowner can do themselves? (Oct 5, 2014) Elizabeth

Reply: gas boiler sooting safety warning: turn it off and call for repair

Elizabeth

Watch out:

If that's the fuel you're using I'd shut off the system and ask for inspection and repair by a licensed plumbing and heating contrator.

This is not a homeowner repair job.

Watch out: there should be NO soot production from a gas burner.

If it's making soot the combustion is improper and unsafe, producing dangerous carbon monoxide - an unsafe condition that could produce fatal carbon monoxide gas poisoning.

See GAS BURNER SOOT CAUSE & CURE for diagnostic and repair steps.

Watch out: for safety, also be sure that your home has properly installed, located, testing, working smoke and CO (Carbon Monoxide) detectors.

See CO DETECTION OPTIONS

For readers concerned about soot formation at an oil fueled heater,

see SOOT on OIL FIRED HEATING EQUIPMENT 

Boiler Water Supply FAQs

Should my boiler water supply stay turned on?

I have a Peerless oil burner. It has a tankless water heater.

My question is is my intake water supply suppose to be turn on and then turned off when the boiler is full?

Or does the water stay on all the time the boiler is on. My brother couldnt remember which level he turned for the winter.

If I leave the water on will it flood the boiler.

I have forced hot water heating.

And I have an electric water heater. I dont want to turn on the water and flood the boiler.

If the water stays on will it damage the boiler? Boiler WB-3 Water 30psi. boiler no.wb-110-wpc On 2017-09-11 by Frank

by (mod) - For hot water (hydronic heat) boilers the automatic water feed valve is normally left "ON"

Frank:

Provided that you are talking about a hot water (hydronic) heating system and not a steam heating system, then

First check that your boiler is at a normal operating pressure

1. Look at the pressure gauge on your boiler - it should read somewhere between 12 psi if the boiler is cold and something just under 30 psi fi the boiler is hot.
   
   For details see GAUGES ON HEATING EQUIPMENT
2. Look at the pressure relief valve to be sure it's not dripping or leaking.
   
   If you don't know what that is, see RELIEF VALVE LEAKS

Next see if your boiler uses an automatic water feeder valve

3. If there is an automatic water feeder valve ( and provided it's working) leave the water valve ahead of that control ON.
   
   In most residential hot water heating systems the heating boiler has its own water supply line and control valve and pressure reducing valve to automatically feed water into the boiler should some leak out.
   
   The boiler and its piping are a closed system that gets filled when installed and that is normally always full and should not use water (unless it's a steam system).
   
   

   Watch out: provided you have a pressure reducing valve like those shown just above, the valve should be set around 12 psi so that it will not raise your boiler's COLD water pressure above 12 psig.
   
   Watch out: most pressure/reducer - water/feeder valves come with an instruction sheet that specifically says the valve is a pressure reducer NOT an automagic water feeder even though everybody uses them for that purpose.

   I have found that after 20-40 years of service a typcial pressure-reducer valve like the 1960's B&G Pressure Reducer shown here become clogged and stop feeding water to the boiler.
   

   In that case the valve won't keep the boiler at 12 psi cold and you'll need to replace the valve.

   
   
   

4. If your boiler has only a manual water feeder valve - which would be unusual on a modern hot water heating boiler, then
   
   Watch out: IF your boiler has ONLY a manual water feed valve AND PROVIDED it is a HOT WATER or HYDRONIC boiler NOT a STEAM boiler, then
   
   do not leave the water feeder valve on as you'll put too much cold-pressure into your boiler and the relief valve will (or should) spill>
   
   If this is your case then you should ask your heating company to install an automatic pressure regulator and water feeder.

About your tankless coil for domestic hot water:

Separate from the heating boiler that's heating your home (just described) is a tankless coil used to make domestic hot water for washing. The tankless coil has its own cold water inlet and hot water outlet that supplies water to the house.

The tankless coil absorbs HEAT from the physically separate hot water inside the boiler and transmits that heat into the water entering the coil from your building water supply system and flowing out of the coil to give hot water at plumbing fixtures.

The coil normally always has its water supply on or open - else you'd have no hot water.

See TANKLESS COILS - home to read abou how your system is making domestic hot water for washing and bathing.

Boiler Makes Heat but Not Hot Water FAQs

We have heat but no hot water

I have an oil operated boiler the runs both my hot water and heat to my house. I have heat for my house but no hot water what could be the problem? On 2019-03-10 by Matt

by (mod) -

• IF your hot water is made by a tankless coil
  
  on your heating boileed tankless coil, or a closed valve, or a scale clogged tempering or mixing or anti scald valve
  
  See more detailed diagnosis and repair help
  
  at TANKLESS COILS
  
  at ANTI SCALD VALVE at TANKLESS COIL
  
  and CLOGGED PIPES / TANKLESS COIL DE-SCALE
• IF your hot water is made by an indirect water heater
  
  then the problem could be a bad zone valve that controls the boiler loop that heats the indirect water heater tank or a bad temperature sensor on the indirect hot water tank itself - see more detailed help
  
  at INDIRECT FIRED WATER HEATERS