Diagnostic questions & answers for TP valves or relief valves used on water heaters, boilers, other water heating devices. Set #2.

This article series explains the requirement for temperature and pressure relief valves on water heaters, calorifers, geyers, or hot water cylinders, and we give relief valve installation, inspection, diagnosis and repair procedures for these important safety devices.

Temperature & Pressure Relief Valve Questions & Answers

These questions and answers about TPR valves or temperature/pressure relief valves on water heaters were posted originally at RELIEF VALVE, WATER HEATER - be sure to review the diagnosis and repair advice given there.

On 2018-12-29 by (mod) - after opening the relief valve we have no hot water

Anon:

IF you water heater is electric

AND the water level in the heater dropped below the electric heating element

AND the heater was turned on

THEN the element may have burned up.

Try first turning the system off and back on

Try also checking for a tripped button on the temperature limit control

Then use the on page search box to find our article entitled

How to Test for a Bad Electric Water Heater Heating Element

let me know how that works for you.

On 2018-12-29 by Anonymous

Someone opened the pressure valve by accident and water heater went into vacation mode and now we don’t have hit water

On 2018-10-02 by (mod) - Two types of temperature/pressure relief valves - water heater vs heating boiler

The relief valve on the boiler needs to be rated at or above the input BTUH of the boiler it protects.

A boiler relief valve is usually set to open at or above 30 psi.

[Click to enlarge any image]

The WATTS 374A model M [shown here) is designed for hydronic heat (hot water boilers) and has a spill or protection capacity of 550,000 BTU/hr - well above (thus in the "safe" direction) the input BTUH rating of your boiler (which you give as 150,000)

The relief valve on a separate calorifier or hot water tank or hot water storage tank such as an indirect water heater will have different specifications. And it is a different design as well.

For example a Rheem ProTec TPR valve (shown above) designed for a water heater has these specs:

Temperature Relief: 210°F (99°C),

Pressure Relief Range: 75 to 150 psi (5.2 to 10.3 bar).

Notice that it is opening at a higher pressure than the TPR valve on your boiler itself. That's because the normal pressure inside of a water heater or hot water storage tank will be greater.

A heating boiler starts at about 12 psi cold and gets up to just under 30 psi hot (at under 200F).

While a water heater (calorifier or geyser) starts at building water pressure that could be anywhere from 30 to 70 psi and goes to a higher pressure as it's heated.

I'm not sure which TPR application you are asking about. So I address both above.

Below the image shows what your Watts TPR valve looks like -

On 2018-10-02 by Peter Kim

Lennox Boiler model CMWB-5 as XEB-5 series with Crown's Mega store 50 for hot water storage is my heating system.

BTU/HR by CMWB-5 is 150000 for INPUT and 123000 CGA OUTPUT.

Due to the problem I have replaced Pressure Relief value with WATTS 354A model M with set to 30 PSI as recommended by pluming parts store. (unfortunately I did not have the tag for old parts.)

Can you tell if WATTS 354A model M with set to 30 PSI is right parts for my heating system?

On 2018-04-09 by (mod) - What size relief valve is normally on a 50 gal hot water heater?

Anon

There is not a single "right" answer to your question.

The relief valve must be capable of discharging hot water fast enough to not b e overtaken by the input BTUH of the water heater. You'll see that the input BTUH varies significantly by water heater fuel source: oil, gas, electric, solar, and not by the water heater size in gallons.

On 2018-04-08 by Anonymous

What size relief valve is normally on a 50 gal hot water heater?

On 2018-01-14 by (mod) - water pooling around the base of the relief valve.

I would pull out the TPR valve and start over with more turns of new pipe dope or teflon tape, after checking that the threads of the tank tapping have not been damaged or stripped.

On 2018-01-13 by George

Installing a new TPV into the top of a five-year old GE water heater. Used pipe dope but there is water pooling around the base of the valve.

I'm cranking with a 12-inch crescent wrench, and getting 20-30 degrees of rotation per mighty heave. Afraid to overtighten and not sure how much is too much. Advice?

On 2017-12-12 by (mod) - why has hot water pressure dropped off

I would look for a defective or debris blocked Anti scald valve or mixing valve.

The more Troublesome course after that will require cutting open the water pipe and inspecting beginning from the point at which it branches off from cold into your water heater.

See details at HOT WATER PRESSURE IMPROVEMENT

On 2017-12-12 by Avinash

I have a 15 litre storage water heater. For the last 4 days, the hot water pressure has dropped off significantly.

The mixer / diverter , when turned for cold water has no problems, its the hot water that is very slow. Its heating alright but no pressure.

i reviewed the inlet faucet for the heater and confirmed its open all the way. What next ?

On 2017-07-19 by (mod) - can I mount the PRV on its side?

George,

No

The temperature/pressure relief valve must

- have its mouth pointing DOWN - else it can clog and blow up the water heater

- have a discharge tube bringing hot water to a safe floor or disposal location - one that remains visible - and the tube cannot be piped "up"

If you can respect those rules as well as the instructions that come with your TPR (PRV in your lingo) you should be OK.

On 2017-07-18 by George williams

I have a side mount prv i need the little bit of room can i put it on the top of the hwh

On 2017-05-04 by (mod) - openign pressure for a T&P valve

Bob

It depends on what type of heating equipment is being protected;

For example a home heating boiler TPR valve like the Watts 335 ASME Boiler Pressure Relief valve, used on smaller boilers up to 510,000 input BUTH at 30 psi (2.11 bar) opens at 30 psi. No temperature rating is even given in the basic specifications.

• The valve opens at 30 psi

In comparison, a Rheem ProTec TPR valve used on water heaters provides

• Temperature Relief: 210°F (99°C),
• Pressure Relief Range: 75 to 150 psi (5.2 to 10.3 bar).

On 2017-05-04 by Bob Trueblood

At what temperature a T&P value would open

On 2017-04-30 by (mod) - no water in my water heater

Jessie:

You made sure by opening the water heater drain, right? And it closed without leaking right?

IN that case it sounds as if the inlet control valve to your water heater is off or blocked. Assuming you have normal cold water flow in your building, start following water pipes to the water heater from the point at which the cold water line sends a branch off to the water heater.

Look for any valves in that route; check that they're open; keep in mind that some valve types (like gate valves) may turn counterclockwise (in the open direction) but may remain closed inside if the valve stem is broken.

Otherwise I'd look for a clog in the piping at valves and elbows.

On 2017-04-29 by Jessie

There is no water at all in my gas Rheem 4 star.

On 2016-10-24 by (mod) - TPR valve keeps opening

Anon:

Check the starting water pressure to be sure it's not abnormally high - say over 60 or 70 psi.

Check that the heater temperature is not set abnormally high - safe is to 120F or less unless you also have an anti-scald valve or system installed.

Other causes of TPR leaks are described

at RELIEF VALVE LEAKS

On 2016-10-24 by Anonymous

New water heater new expansion tank and 2nd new relieve valve why is the valve still opening to release pressure?

On 2016-09-04 by (mod) - water heater leaks only when hoht

Deb

The water heater may leak only when pressure and temperature are increased in the heater.

You are right to leave the heater shut off and to call for repair.

If the leak is at a fitting the heater may be repaired.

If the leak is in the heater tank itself it needs replacement.

Watch out: If the heater is at over temperature or over pressure the system is extremely unsafe if the relief valve is not opening, risking

a BLEVE EXPLOSIONS

On 2016-09-04 by Deborah

water heater leaking only when hot water runs via a shower. Drip pan was full. TPR valve bone dry. I'm scared. Don't want it to blow so shut off circuit breaker and water valve.
can't figure the leak.

Any thoughts. It's labor day weekend. Want to wait to call a plumber on Tuesday. Can I leave everything on or keep it shut off?

Question: Leaky pressure relief valve blamed on bad expansion tank bladder ?

I have a weil McLain hot water boiler, which is about 20 years old. It was leaking out the pressure relief valve, so we changed out the expansion tank which had a bad bladder in it, as well as the pressure relief valve,

but now I noticed it has continued to leak out of the new pressure relief valve when the boiler is running. Any ideas? - Vincent Nizzardi

Reply:

A bad expansion tank bladder would certainly be a cause of relief valve leakage. As you replaced both the tank and the TP valve, and now see a leak at the new valve, there are other possible explanations such as:

• dirt on the valve seat due to crud that flowed into the valve during testing after installation. A technician might try flushing the valve and gently tapping the lift rod to be sure the valve is seated properly.
• high water pressure in the boiler - check the water pressure with a reliable gauge
• high boiler temperature
• a defective automatic water feeder that is putting too much water or water at too high a pressure into the system
• a leaky tankless coil that leaks into the boiler
• you may need an expansion tank on your water heating system. See the explanation and cure described in the article above at Closed Hot Water System & Thermal Expansion Problems.

Keep us posted - what you learn may help other readers. - Editor

Question: Do I also need a TP valve on the cold water line? What about a check valve on the cold water supply main line?

Do I need a pressure-relief valve on the cold waer pipe that feeds my hot water heater tank? - Watts

Do I need to install a check valve on the cold water supply main line? Is it safe to do so? - Watts

On a municipal water supply system, do I need a check valve on the cold water line if a TP valve is installed on the water heater? - Watts

Reply: no

No, there is no need for a separate pressure relief valve on the cold water line feeding the water heater. That's because water pressure within the system is common throughout all of the plumbing system: cold water line into the tank, hot water in the water heater, and hot water in the hot water lines leaving the water heater tank all see the same pressure. [10]

... the original purpose of a check valve was to protect the [water] meter by preventing superheated water from backing up into the cold supply main from range boilers and heaters.

However, the very condition that can cause this, can also cause explosions and the temperature and pressure relief valve principle protects against both excessive temperature and [excessive] pressure, thereby eliminating the need for a check valve.

A check valve closes the [plumbing] system, thereby allowing pressure to build up from thermal expansion higher than the city main pressure, and therefore should not be used except where required by local codes. [10]

Note: We add that there are other reasons for a check valve or backflow preventer valve on water systems: to prevent water from the building from flowing backwards into the city supply mains during an interval of loss of pressure in the mains.

Should such a pressure loss occur the risk is that unsanitary water from buildings connected to the mains could flow backwards into and thus contaminate the water supply mains in a community.

Most community water supply systems include a pressure regulator combined with a backflow preventer or check valve at the water meter. Watts' note above was penned in 1973. The company may have more to say on this topic today.

When a hot water system includes a temperature & pressure relief valve installed on the water tank or heater there is no advantage to installing a check valve to protect the water meter - as Watts explained in the quotation above.

Watts points out that if a check valve is installed on the cold water line to the water heater, a result is a pressure rise in the system each time water is heated in the hot water tank.

Question: What is an "open main" water system and does it have safety implications for water heaters?

Does the water pressure in my house plumbing system ever increase under any circumstance (hot water heater or something else) on an open main water supply system? - Watts

Reply:

In an "open main" system nothing is closed between the house [plumbing] system and the street main. Therefore, water pressure [in the house] cannot increase above the street main pressure from the reservoir regardless of any expansion [in the hot water system] from temperature. Consequently, a straight pressure relief valve cannot operate unless a system is closed.[10]

Note: By "straight pressure relief valve" we think Watts means a valve that responds only to water pressure and that does not include a response to hot water temperature. Such a system could be unsafe.

Question: Why is hot water pressure going up to 150 psi in my water heater tank?

I had to install a new temp controller in my hot water tank. It is a bourdon tube type and I installed exactly like the original one. The water in the tank is heated by a coil as a separate zone from the furnace. The house water pressure is about 50 psi. I have the tank temp set at 125 degrees.

I installed a pressure gauge between the pressure relief valve and the top of the tank. When the hot water from the furnace enters the tank the water pressure goes from 50 psi to 150 psi and the relief valve discharges a little and then stops. The water temp is 101 degrees at this time. Why is the hot water tank pressure increasing to 150 psi? - Alan

Reply:

Alan you may need an expansion tank on your water heating system. Heating water in a closed container increases the pressure. See our discussion above about Closed Hot Water System & Thermal Expansion Problems.

Question: can I use a combination of check valve and pressure-only relief valve to protect against overheating my hot water tank?

Will a "straight" pressure-only relief valve prevent overheating and thus keep my hot water system safe if a check valve is also used?

Reply: No. Such a system is unsafe

No. Overheating in the hot water system depends entirely on the BTU input rate to the water heater.

A relief valve that operates on pressure only (ignoring temperature), regardless of its size or rated discharge capacity, can't prevent overheating nor reduce temperature. Such a sysetm is unsafe.

Question: will the relief valve affect building water pressure delivered to faucets?

Can the relief valve affect the pressure of water coming out of faucets? - Pam Gregg

Reply:

No, Pam, not under normal circumstances. That's because hot water leaving the water heater may pass BY a relief valve en route to your faucets (depending on where it is installed) but the water is not passing THROUGH it.

But if a water heater pressure-relief valve were stuck wide open flushing hot water continuously down a drain, building water pressure would probably fall noticeably - that would be an unusual circumstance and surely you would know it, from the flooding water out of the valve and quickly by the loss of hot water.

Question: using the "easing lever" on TP Valves? When should a TP valve be replaced?

I don't understand how simply lifting the "easing lever" verifies that the temp./psi. relief valve is intact and will function properly at factory set limits. Most water supplies have trace elements , including some non- toxic metals.

These elements usually collect and build up on the sensing stem of a water heater relief valve. If a relief valves "easing lever " is tripped, valves with lime and trace metal accumulation often will not re-seat, resulting loss of heated water,shutting off the water supply to the unit, shutting down the power to the unit, ordering a new relief valve and installing the replacement. It's seems to thoroughly test a water heater relief valve, Psi. and temp. limits would have to applied that would require the relief valve to engage.

Once a relief valve has released at its set point it should never be put back into service. - Ken Hansen

Question: since a TP valve releases excessive pressure in a water heater or boiler, isn't pressure-release enough protection against a water heater tank explosion?

If the condition of too much hot water pressure is corrected by the automatic opening of the pressure/temperature relief safety valve or "blowoff valve", why was I told that a water tank can still blow up?

Reply: relieving pressure alone won't prevent a hot water tank from exploding - that's why a TP valve also responds to temperature and the TP valve has to release heat at a rate equal to or greater than the BTU input rate for the water heater

One would think that the TP valve alone would always be enough protectin on a water heater tank. But as Watts Regulator Company explained back in the 1970's and as was demonstrated in the film "Explosion Danger Lurks", even a wide-open pressure relief valve can not prevent water in a water heater tank from becoming overheated.

At WATER TANK PRESSURE CALCULATIONS we discuss the calculations behind the increase in temperature and pressure in an enclosed water tank or water heater tank. In the case of a hot water storage tank, Watts points out that

The reason that the volume of pressure discharge [through the relief valve] is not enough to overcome the BTU heat input [into the hot water heater tank] is because thermal expansion pressure is approximately 2 1/2% of volume for every 100 degree rise. [The] fluid heat discharge ... necessary to relieve the extra BTU heat input for every 1000 heat units is about 20 times greater in volume.

In a [hot water heating] system with a check valve and a pressure relief valve, the relief valve opening by pressure increase due to expanding water will discharge approximiately 1/2 lbs. of water for each 1,000 heat units (BTUs) put into the water - because that is the rate at which the water expands when heated.

To release 1,000 heat units when the temperature is at 210-212 degF, there must be approximately 6 2/3 lbs. of water released from the system. In other words, to prevent overheating [water in the hot water storage tank] a means must be provided to relase about 20 times as much water from the system as a pressure relief valve can discharge from thermal expansion [alone], when there is a check valve in the supply line or [when there is] an accidental stoppage [of the water piping] to make the system a closed one.[10]

In other words, in a closed hot water piping system (closed by the presence of a check valve or a blockage in the water piping to prevent expanding hot water from "pushing" water volume back out of the watertank, to prevent a hot water tank from overheating, the TP valve has to discharge heat [not pressure] at or greater than the rate that the heater's burner or electrodes are putting heat into the water in the tank.

But on a typical water heater, the heat input rate in BTUs is about 20 times more than the heat output rate through a TP valve if it operated on pressure alone.

Watch out: the conclusion of this technical discussion is that it is absolutely essential that the BTU (heat or energy) dumping rate for a TP valve must be properly matched to the BTU input rate of the heater. And a pressure-only relief valve on a water heater, that is excluding a valve that also responds to temperature, would be an unsafe installation.

Question: figure out this relief valve problem

(Feb 20, 2012) Jeff Garmel said:

I had a new water heater installed. It leaks at the relief valve. There is a 10-15 year old Amitrol Therm-x-trol ST5 (2 gallon) expansion tank on the cold water line before the heater. is it possible that the installation drained the air out of the tank? thanks Jeff

(Mar 7, 2012) Sunil Jay said:

Water is leaking from the bottom opener near electric connection. Is it through the heating element bushes

(Mar 7, 2012) sunil_nemindra@yahoo.co.nz said:

Very fast and reliable guidance. Thank you.

(May 26, 2012) pam said:

there is water coming out of my hot water heater and it's making a funny noise the water is turned off and so is the gas

Reply:

Sunil,

I have found that leaks anywhere in a water heater will often appear as both water on the floor and water appearing at the water heater tank metal jacket bottom and vertical sides around the heater base where there is a sheet metal seam. In other words the leak may be from somewhere higher up.

You should not try to remove the heater jacket, but you can remove the covers over the electrical water heater controls and elements (if yours is an electric heater as your message suggests). That will give view of the mounting of the two heater elements and you will see directly if the leak is from one of those locations.

Send along photos if you like and I can comment further - use the CONTACT links found at page top or bottom.

(May 29, 2012) (mod) said:

Pam if the water is leaking out of the heater itself it's probably time to replace it.

Question: is a TP valve required on a wall mounted water heater?

(Oct 2, 2012) Bill Miller said:

Is there a rule or code on how many 90 degree 3/4" fittings can be used on the drain line of a T&P at a 75 gallon State water heater?

(Oct 4, 2012) James said:

IS a TP valve required for storage wtaer heaters that are wall mounted, 50 liter capacity. I ahve noted that most household storage water heaters in the middle east have on TP valve except a releif valve on the water INLET of the heater.

Yet all these are listed and registered to be complying with the IEC 60335-2:2002 Household and similar Electrical appliances: Storage Water heaters? would appreciate guidance. cheere

Reply:

James a temperature and pressure relief valve is required on any hot water tank or cylinder regardless of how the tank is mounted.

James, yes. I worry that a relef valve on the cold inlet is not what the manufacturer specified, and that even if it responded to overpressure it won't respond safely and reliably to an over temperature condition.send us brand and model numbers for research.

Question: tested the TP valve now it keeps leaking

(Dec 2, 2012) Sun said:

After lifting the lever of temperature and pressure relief valve for annually maintenance,hot water leaking for hours, I wonder when its stop?

Reply:

Sun,

Tap gently on the pin that pulls the valve open. If that doesn't reseat the valve, and if flushing the valve doesn't remove debris from the valve seat it's time to replace the valve.

Watch out: a temperature/pressure relief valve that keeps dripping is unsafe and could risk becoming clogged, failing to open on overpressure and leading to a dangerous or even fatal boiler explosion.

See BLEVE EXPLOSIONS

When in doubt replace the valve. You should be using a heating service professional.

Also check for abnormally-high system water pressure and water hammer problems in the building.

Question: Thermal expansion valve on cold line leaks

(Dec 22, 2012) charles said:

I have a thermal expansion valve that is installed on my inlet line (cold water line going into my hot water tank) that is leaking, now the question that I have is, is it required to be on the inlet line . Talking to a few friends that do plumbing and they are saying that it is not required, but they recommend that I install a expansion tank.

So, another question is if the system was installed without a expansion tank is it a good idea to install one are just replace the thermal expansion valve that was installed when the hot water tank was installed, are just remove the old system and install a new hot water tank system per new system directions ? So many questions, but can't find all the answers! NEED HELP !

Reply:

Sounds like you need an expansion tank but first I'd check for any other sources of abnormal system pressure such as water hammer.

Question: Rheem PVW50 TP valve leaks

(Jan 11, 2013) Wayne said:

I have a 9 year old Rheem PVW50. Last year I replaced the drain valve, T&P valve and the anode rod. The old anode rod was worn out.

A couple of months ago I noticed the T&P valve was leaking every once in a while. Then it started every day.

I read an article that said if the T&P is leaking to open the cold water faucet, if the T&P stops dripping it is not the water heater.

But to check it out get a watts gauge with high pressure marker. So I purchased one and found out the cold water was going up to 110 psi and hot water heater up to 150 psi. Found out I need to replace the Watts Pressure Reducting Valve AU25B.

After replacing valve cold side is now 50 to 60 psi. However, the hot water heater registers 50 to 60 and when the water is being heated may go up to 100 psi. No water is leaking out of the T&P valve or anywhere else. Putting my ear to the heater I can hear a little grumbling out of the tank but not overly so.

So my question is 2 fold. First, is the water pressure of 50 to 100 in the tank ok? Secondly, when is the best time to replace the tank but still get maximum usage out of the water heater? I've been told by a friend at Rheem that they have seen 15 to 20 years out of the tanks.

Reply:

Opening a cold water faucet isnot a proper fix for a leaky TP valve. Replace the valve; if the new one leaks check the system temperature and pressure; Your system may need a hot water expansion tank.

Question: Nipple between water heater and TP valve

(Feb 12, 2013) Ethan said:

Hello! I have a question here, not addressed by any web info I can find:

Is it against any code to have a nipple (about 1" long) installed in between water heater and the T&P valve? (instead of having the T&P valve threaded directly into the tank). I'd rather not use an extra-long T&P valve. Much thanks!

Reply:

In my OPINION the installation you describe is improper and unsafe and if it violates the manufacturer's installation instructions, indirectly by that error it's "against code" as you put it.

The short nipple you describe raises the valve, reduces the depth of extension of its temperature sensor into the water heater, so is improper.

Question: O ring blew in mixing valve - is there a sticking relief valve problem?

(Mar 4, 2013) ron goodrick said:

hi there just replaced an expensive basin mixer cartridge leaked installed new one .. 3 days o ring blew in hose //sticking temp relief valve ? dodgy taps ??

Mar 6, 2013) SOMIDI MAHESHWRA said:

IF A SAFETY VALVE IS GETTING RELEAF AT 250 Deg centigrade and presuure 20 kgs/sq cm if my temperature is 30 deg centigrade what is the pressure of release in kg/sq cm.

Reply:

These questions are a bit unclear leaving us reluctant to guess at an answer.

Watch out: if your TP valve is "sticking" - that is not opening when it should, the system is unsafe. See BLEVE EXPLOSIONS

Question: Washing machine blows the TP valve

(Mar 16, 2014) mike said:

I have a front loader washing machine and it blows the T&P Valve on my electric hot water tank. Any solution on how to fix this problem. I have put in a pressure reducer coming into the house and water hammer behind the washing machine and nothing.

Should I replace the T&P valve again since it has blown 50 plus times. Only with the washing machine nothing else it blows

Reply:

I'm unclear how the washer is causing the TP valve to blow or leak - and because there could be a very serious safety hazard involved, some accurate diagnosis is in order.

For example, if the problem is due to water hammer caused by the washer operation, there are water hammer control devices you can install at strategic locations on the system to solve the issue - search InspectApedia.com for

WATER HAMMER NOISE DIAGNOSE & CURE to read details.

But if the washer cycle is for some reason causing the hot water source - a water heater - to overheat or malfunction, that could be a serious safety hazard.

Question: new TP valve for new water heater?

(Mar 29, 2014) henry parker said:

when I buy a new water heater do I also need to buy a temp relief valve?

Reply:

Absolutely, if a TP was not included with the heater. Be sure to buy the proper valve matched to the water cylinder (heater) capacity and design and mount location.

I would never risk re-using an old TP valve on a new heater.

Question: why is just one TP valve leaking?

(Mar 29, 2014) C. David Hensley, cdjhensley@morrisbb.net said:

30 gallon water heater less than a year old with pop-off value leak, I have replaced the value, city water pressure is 40 -45 lbs., heat controls on 120 degrees top and bottom, this is the only water heater out of 12 apartments in the same building that leaks. What happen?

Reply:

C. David,

You want to diagnose the reason the valve is leaking. At the ARTICLE INDEX at the end of this article click on

RELIEF VALVE LEAKS

...

Continue reading  at RELIEF VALVE, WATER HEATER - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see RELIEF VALVE, WATER HEATER DIAGNOSTIC FAQs-3 - more-recent questions and answers about TPR valves on calorifiers, geysers, water heaters

Or see these

Recommended Articles

• GAS WATER HEATER AUTOMATIC SHUTOFF - temperature operated gas supply shutoff for water heaters, Watts 210-5 series
• HOT WATER PRESSURE EXPANSION RATE - how much does water expand when you heat it?
• HOT WATER EXPANSION TANKS - how to cure the problem of leaks in heated hot water systems, calorifiers, water cylinders
• RELIEF VALVES - TP VALVES
• WATER HEATER SAFETY
• WATER HEATER TEMPERATURE ADJUSTMENT CONTROLS

Suggested citation for this web page

RELIEF VALVE, WATER HEATER DIAGNOSTIC 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 T&P RELIEF VALVES

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INDEX to RELATED ARTICLES: ARTICLE INDEX to PLUMBING SYSTEMS

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