Recent hydronic (hot water) heating boiler problem diagnosis and repair FAQs #2.

This website answers questions about all types of heating systems, advising on troubleshooting, inspection, diagnosis, and repairs. We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors of common heating system defects.

Heating Boiler Diagnostic FAQs2

These questions & answers about troubleshooting or fixing a heating boiler (hot water heat, hydronic heat, baseboards, radiators &c) were posted originally

at DIAGNOSE & FIX HEATING PROBLEMS-BOILER - home. Be sure to review that article.

Below is our index to questions and answers about heating boiler troubleshooting and repair.

Article Contents

• ADDING WATER to the BOILER - trouble with water feeders
• AIRBOUND HEAT - cold baseboards, radiators, noisy pipes
• BOILER CONTROLS - settings, substitutions, replacements
• BOILER CONVERSIONS - change boiler types, controls
• BOILER EFFICIENCY
• BOILER HEAT EXCHANGER DAMAGE - cracks, odors, sooting, safety
• BOILER LEAKS - where, why, how to fix
• BOILER LEAKS CORROSION STAIN FAQs
• BOILER NOISES - to fix the noise we start by finding the source
• BOILER ODORS
• BOILER PRESSURE
• BOILER PUFFBACK DAMAGE - is the boiler damaged?
• BOILER SHUTS DOWN - boiler won't keep running
• BOILER TEMPERATURE TOO HIGH - unsafe, boiler is too hot
• BOILER WATER SUPPLY -
• CAST IRON BOILER & RADIATOR PUSH NIPPLES
• CHECK VALVES, HEATING SYSTEM FAQs
• CIRCULATOR PUMPS on BOILER SYSTEMS
• COMBUSTION CHAMBER or CHAMBER LINER DAMAGE
• GAS BOILER BURNER SOOT - soot anywhere at or on gas fired heating equipment is a danger sign
• HEAT WON'T TURN OFF - radiators or baseboards still hot long after call for heat was satisfied
• HEAT WORKS but NO HOT WATER - boiler is supposed to make both
• HOT WATER but NO HEAT - boiler runs, makes domestic hot water but stops delivering heat
• HOT WATER NOT HOT ENOUGH - boiler heated indirect water heater or tankless coil just tepid or warm
• NO HEAT, BOILER RUNS - no heat delivered to some or all areas, but the boiler runs
• NO HEAT, BOILER WON'T RUN - boiler won't start & no heat is delivered anywhere
• NO HEAT DOWNSTAIRS - but upper floors are getting heat
• NO HEAT UPSTAIRS - but lower floor(s) are getting heat
• NO HEAT ZONE VALVE STUCK
• NO HOT WATER but DO GET HEAT - boiler runs, makes heat but not making hot water
• NOT ENOUGH HEAT DELIVERED - to some or all areas, though the boiler runs
• OIL BURNER DIAGNOSTIC FAQs - index to all oil burner diagnosis and repair Q&A
• RELIEF VALVE LEAK FAQs
• RISKS of HAVING NO HEAT - health, freezeups, other
• STEAMING HOT WATER BOILER - hydronic boilers should never be releasing steam
• TOO MUCH HEAT DELIVERED by BOILER - baseboards or radiators are too hot or rooms get too hot

We're sorting out the reader Q&A below and will re-post all of these pages soon.

Meanwhile use the on page search feature of your browser if you don't want to wade through the page. - DF

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Boiler Pressure FAQs

Why does my boiler pressure rise over 30 psi?

What can cause the boiler pressure to rise spontaneously to over 30 psi,even though the pressure was 12 psi when filled? Note the expansion tank and PRV are brand new and the water feed ball valve is shut. On 2018-11-03 by Bruce

by (mod) -

Bruce:

Causes of abnormally high pressure in a residential heating boiler (hydronic heating system - i.e. hot water heat) include

1. a defective automatic water feed valve

2. a defective or improperly-set building water pressure regulator

3. a leaky tankless coil in the boiler: a hot water coil or tankless coil in the boiler, if leaky, will leak water into the boiler from the higher-pressure building water pressure side.

More details are at:

TANKLESS COIL / HOT WATER COIL LEAKS

RELIEF VALVE LEAKS - some of the causes of a leaky relief valve can also cause high boiler pressure)

PRESSURE & TEMPERATURE SETTINGS, CONTROLS

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Hot Water Baseboards or Radiators Won't Turn Off

Radiators still get hot with boiler switched off!

Why would radiators still get hot with boiler switched off! On 2018-01-18 by Artb

Reply by (mod) -

Art

at HEAT WON'T TURN OFF (found by searching InspectApedia.com for that phrase) we list a number of reasons that heat may continue to pour out of radiators even with the boiler off.

Examples include normal thermal mass remaining in the water-filled steel or cast iron radiators and thermal convection circulation of hot water out of the boiler,

or

perhaps because a check valve that is stuck open

or

a zone valve that is stuck open

or

thermostat wires shorted together calling for heat

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Can't refill boiler after partial draining to replace a gauge

I have a Dunkirk boiler that had a bad temp/pressre gauge go bad. On 2018-01-07 by Darius

I replaced it.

Now I can't get the boiler to fill back up.

Is the reducing vavle bad ?

The boiler was still hot when I was trying to refill or burp it.

by (mod) - pressure reducers not reliable water feeders

Darius

Yes, probably that's the problem.

I have run into this problem too: nobody knew that the automatic water feeder/pressure reducer was not feeding the boiler until we drained the boiler for service.

You'll want to replace that valve. Meanwhile if there is a manual bypass loop and valve you can fill the boiler by that means.

See details

at WATER FEEDER VALVE, HYDRONIC BOILER 

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Continue reading at DIAGNOSE & FIX HEATING PROBLEMS-BOILER - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• BOILERS, HEATING
• BOILER OPERATING PROBLEMS
• DIAGNOSE & FIX HEATING PROBLEMS-BOILER
• OIL BURNER INSPECTION.
• GAS BURNER FLAME & NOISE DEFECTS
• GAS BURNER SOOT CAUSE & CURE
• GAS BURNER PILOT LIGHT PROCEDURE
• RADIATORS for ROOM HEAT - topic home, for cold radiator or baseboard diagnosis and repair

Suggested citation for this web page

DIAGNOSE & FIX HEATING BOILER, FAQs-2 at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING BOILERS

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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