Advice or Information greatly appreciated on prvs & driers

Hello all,

first of all i wasnt sure what section to post this in but being that its on a commercial site of mine i thought id post it here.

Basically i am after some information or regulation if there is any for this specific subject.

A site i look after hasnt had the PRV's replaced since the kit was installed (2015) most of my sites usually have them replaced every 3-5 years but this site doesnt seem to like the idea of replacing them, is there any regulation that says they need replacing every 3-5years or is this just what the manufacturer's specify?

Also the same site hasnt had any of the liquid drier cores replaced since 2016, again i was under the understanding that best practice was to replace them every 2-3 years unless the system has been opened to work on it or had a leak then you replace once the system is repaired and back operational.

Any advice, information or general input would be appreciated.

No requirement to replace filter driers unless you suspect they are blocked, I wouldn't replace them unless opening system.

The PRV's are covered under the PED, think it is every 5 years.

Brilliant thanks for the info

Usually there is a moisture indicator downstream of the drier, and if it changes color (from green to yellow in my part of the world), that is a sign you need to replace the drier cores.

Here relief valves are "supposed" to be changed every 5 years. This is fairly well enforced on ammonia systems, but rarely noticed on HFC systems.

MrFreez717

Relief valves are last line of defence.
They will “ probably” open at correct pressure, may, or may not reseat.

High pressure safety switches should be checked & calibrated at least annually as a minimum, doesn’t cost that much, but let them know at least.


Explain how much refrigerant costs & might help the cause.

As MrReeze717 indicates, no one does it.

Annual replacement of PRVs on chillers were required by some of our customer's insurers.

Quote:

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Originally Posted by MrFreez717

Usually there is a moisture indicator downstream of the drier, and if it changes color (from green to yellow in my part of the world), that is a sign you need to replace the drier cores.

Here relief valves are "supposed" to be changed every 5 years. This is fairly well enforced on ammonia systems, but rarely noticed on HFC systems.

MrFreez717

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Thanks for the info MrFreez, yeah the system does have the moisture indicators and while i do check these i have been told that they can discolour and stay yellow no matter what you do? but as these were bright yellow they did give the go ahead for the driers to be replaced.

The prv's they are not getting done due to the cost and apparently as the insurance company has never asked to see the certificates on them the site are not bothered by it.

Quote:

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Originally Posted by RANGER1

Relief valves are last line of defence.
They will “ probably” open at correct pressure, may, or may not reseat.

High pressure safety switches should be checked & calibrated at least annually as a minimum, doesn’t cost that much, but let them know at least.


Explain how much refrigerant costs & might help the cause.

As MrReeze717 indicates, no one does it.

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Thanks Ranger, always check the hp and lp switch and make sure its cutting in and out as set, if they are ever out we replace them just to be sure.

Quote:

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Originally Posted by frank

Annual replacement of PRVs on chillers were required by some of our customer's insurers.

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Hey Frank, wow ive never heard of them being changed that regular.
Unfortunately the way my customer see's it is if the insurance isnt asking for it to be replaced or to see calibration/install certificates they are not bothered.

All i can do is to keep mentioning it on site visits and that way if it ever does blow a prv i can say i have been advising them to replace for x amount of time

PRVs (Pressure Relief Valves) and driers are important components in many HVAC (heating, ventilation, and air conditioning) systems. Here is some information on each:
Pressure Relief Valves (PRVs):
PRVs are designed to protect HVAC systems from overpressure conditions. They are typically installed at the discharge side of the compressor and are set to open at a predetermined pressure level, allowing excess pressure to be released from the system.
PRVs come in different types, including spring-loaded, bellows, and pilot-operated. Each type has its advantages and disadvantages, depending on the specific application.
Driers:
Driers are used to remove moisture and contaminants from HVAC systems. They are typically located in the liquid line, and their function is to trap moisture and other contaminants before they can damage the system.
There are several types of driers, including filter driers, suction line driers, and liquid line driers. Each type has its unique features and benefits, and the choice of drier depends on the specific application.
When choosing PRVs and driers for your HVAC system, it's important to consider factors such as the type of refrigerant being used, the size of the system, and the operating conditions. Consulting with a qualified HVAC professional can help ensure that you select the right PRVs and driers for your system.
Regular maintenance and replacement of PRVs and driers are also essential to ensure the proper functioning of your HVAC system. Be sure to follow manufacturer recommendations and work with a qualified technician to ensure that your system is functioning optimally.

I agree with all you guys except that the PRV's must be changed every 5 yrs.
The decision as to when they are changed / Tested is in the UK , a decision usually decided by the site Insurance Companies Inspector.
The size and type are determined at time of manufacture to comply with Pressure vessel regulations and are given CE accreditation.
They are sited at various locations within a system and their operation is also affected by where (what vessel they are protecting) the are sited. Unless the Vessel (Read Concentration \Volume of refrigerant) is above 250 Bar Litre's.
I have seen many Chiller Receivers that have don't have PRV's and only have Thermal Plugs. In fact on York Chillers unless it has changed since I retired the fitting of PRV's was a customer option.
With regard to Filter driers in my experience unless an issue with one is being suspected you leave well alone.
Is it not the current advise that unless absolutely necessary you do not Break into a system..
Tricky your last reply is the norm for most.
When all is said and Done.
Safety and Good service practice can conflict. Common sense and a Good Insurance Assessor is Paramount.
Grizzly