Heating boiler gauge replacement: this article describes the steps in replacing a pressure or temperature gauge on a hot water (hydronic) boiler or on a steam boiler.

We give two different approaches to boiler gauge replacement, a wet process that is done without draining the boiler and a dry gauge replacement process that requires draining water out of the heating equipment.

Q&A on How to Replace a Heating Boiler Pressure Temperature Gauge

These FAQs on how to replace the pressure/temperature gauge on a heating boiler gauge were posted originally at BOILER GAUGE REPLACEMENT - be sure to see the step-by-step guide given there.

On 2019-01-22 by (mod) - Why does my boiler temperature gauge have two needles, Black & Red?

Thanks for a great question.

The black needle tells us what pressure the gauge is sensing or reporting as boiler pressure.

The red, adjustable, needle permits a technician to set what's simply a "marker" or "indicator" that might be used

to set a recommended pressure level (or maximum) that has allowed for variations in elevation of the heating system above sea level (as the gauge was factory set assuming working at sea level or 1 ATM)

to warn a client that the system pressure is exceeding what's recommended.

For example:

in the UK British Gas gives this advice

Usually, on the front of your boiler, you’ll find a water pressure gauge. If you have a hydraulic pressure gauge, you’ll see low and high pressure indicated by red sections on the dial.

The position set when the boiler was installed is sometimes shown by a red indicator needle. On most digital gauges, you’ll see a flashing pressure reading, if there’s a low (or high) pressure warning.

If your boiler pressure reads less than 1 bar, it’s possible that you might have lost water from the system, which needs to be replaced. This is where that filling loop (or filling link) comes in again!

If the pressure gauge on your boiler indicates high pressure (above 2.75 bar), then you may need to bleed a radiator to bring the level down to around 1.5 bar.

This can be tricky and, occasionally, dangerous; due to high water temperatures. We recommend an engineer take a look if you are experiencing high pressure – this could be a result of a fault inside the boiler and may need an engineer visit to rectify.

Additionally, reducing pressure by bleeding a radiator may take some time, and you will need some method of catching the water to prevent damage to wall and or floor coverings.

Above all, be careful. This water is very hot, so maybe get an engineer to do it.

Original source: https://www.britishgas.co.uk/home-services/boilers-and-heating/guides/boiler-pressure.html

On 2019-01-21 by Bill

Why does my boiler temperature gauge have two needles. A black one and a manual adjustment red one?

On 2016-01-12 by (mod) -

If there is water at the proper level, ask your service tech to check for surging.

If there is no water in the sight glass, just droplets, the system is unsafe, should be shut off, and it's water feeder reoaired.

On 2016-01-10 by Sandie

The gauge developed condensation inside when it was zero degree outside and the boiler was on what seemed like every hour.

The condensation dissipated when the weather got a little warmer and the boiler was on regular intervals. What should I do about that. It never happened before.

Should I get it replaced or ?

On 2015-10-14 by (mod) -

From just your e-text I can't diagnose the trouble; but you could attache an independent pressure gauge to your boiler - at the boiler drain - to have another monitor of boiler pressure.

See https://inspectapedia.com/water/Water_Pressure_Measure.php

On 2015-10-14 by JALAAL

I was adding water in to my boiler but the pressure gauge went down again when it gets to 10 psi . Please help is something wrong with my boiler

On 2015-02-22 by (mod) -

I'd give the service manager a call to ask for hel with the gauge, explaining that it was replaced but is not working.

On 2015-02-17 by Ruth

One more question -How long should it take to replace a Pressure/Temp gauge on the boiler and do you have to drain the system to replace the gauge properly? Thank you again.

To (mod) I am having alot of trouble with NJR Home Services who replaced the Pressure/Temp gauge on the boiler.

Do you have any suggestions how to get them to rectify the problem? Who should I contact beside them. I did have a plumber come out to tell me the Pressure/Temp gauge was broken and he replaced it.

I have a contract with NJR Home services and I want to cancel it, but they said I will have pay for their services. What action can I take against them to get this problem resolved. Can you help as to whom I should contact for their faulty services? Thank you.

On 2015-02-17 by (mod) -

perhaps the gauge or its sensor was damaged at installation

On 2015-02-17 by Ruth

What would cause a pressure/Temp gauge to get stuck at 70psi after it being replaced? This gauge was replaced on my Weil-McLain II Boiler.
Thank you.

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Continue reading at BOILER GAUGE REPLACEMENT - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Heating Boiler Pressure Gauge Articles

• BOILER CONTROLS & SWITCHES
• BOILER GAUGE REPLACEMENT
• BOILER PRESSURE & TEMPERATURE SETTINGS
• BOILER PRESSURE CONTROLS & SETTINGS
• GAUGES, HYDRONIC BOILER
• GAUGES, STEAM BOILER
• PRESSURE REDUCING VALVES
• RELIEF VALVES - TP VALVES

Suggested citation for this web page

BOILER GAUGE REPLACEMENT FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING SYSTEMS

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