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The relief valve should be at least as large (in BTU/hr capacity) as the input of the boiler. A 3.5 million input boiler would need then a relief valve to handle at a minimum 3.5 million BTU/hr.

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Q: How do you size a boiler relief valve?
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What to do if your furnace keeps blowing water out of the relief valve?

Nothing as a furnace is scorhed air a BOILER is either water or steam and "Relief Valves" are for liquid thus either you have a boiler or your furnace is being flooded from an outside source


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They serve two different purposes. An air bleed valve is used to remove air from the circulation system. A pressure relief valve is designed to automatically open when certain pressure levels are reached.


Why does a boiler explode?

Low water level along with both a defective high limit safety and pressure relief valve.


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Can a broken thermostat on an oil boiler cause hot water to flow out through the expansion pipe?

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Why does a house boiler pressure relief valve drip water constantly?

if it's dripping water constantly even when cold most likely your pressure reducing valve on the in coming water is letting in more water than it should causing the pressure to rise, if it just happens when the boiler is calling for heat it's probably your expansion tank, it could be water lodged and needs to be drained and re pressurized or replaced. make sure the pressurizer relief valve is not dripping before your boiler reaches 30 psi, that's what they are usually set for on house boilers, if it is dripping before reaching 30psi it's a faulty pressure relief valve that needs to be replaced


Can you use a bladder pressure tank even though the bladder is leaking?

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How do you test a safety valve of a Boiler?

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What is the application of boiler stop valve?

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Where does the pressure relief valve goes on a coil for domestic hot water coming out of boiler?

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