Are mixing valve repairs/failures common?

[Sawyer]

Is it necessary to install ball valves and unions on all three branches of the mixing valve for servicing?

are troubles infrequent?

Can the valves be repaired without removal of the body?

Thanks!

 

[juddspaintballs]

you could buy one with the unions already
http://www.pexsupply.com/Honeywell-Sparco-AM100R-UT-1-1-2-NPT-Union-Mixing-Valves-heating-only

 

[Sawyer]

you could buy one with the unions already
http://www.pexsupply.com/Honeywell-Sparco-AM100R-UT-1-1-2-NPT-Union-Mixing-Valves-heating-only

I do not know how I missed these!

Thanks a lot ;-)

 

[stee6043]

My Danfoss valve is completely servicable without removing the body. That being said, I still have ball valves within a couple feet on all sides....

 

[Sawyer]

My Danfoss valve is completely servicable without removing the body. That being said, I still have ball valves within a couple feet on all sides....

For the additional $12, I also will install the ball valves. As Heaterman said better now than tearing everything apart later".

 

[CozyMan]

Easy to be confused about a mix valve.

The ones shown above (pexsupply.com) are for mixing the water temperature down. For example, radiant floor slab, etc. These have a limited maximum temperature.

When talking about High Efficiency boilers you need a mix valve that maintains a minimum temperature. Very different animal. Much like the thermostat in your car that keeps your engine at a certain operating temperature, the Valve on your boiler (Danfoss, Termovor, Laddomat, etc) are made to keep the operating temperature on the boiler above a certain point; a limited minimum temperature.

Yes, they can fail. And time will almost certainly prove that without ball valves your mix valve will fail early... that's usually the luck. Also, be sure to install a ball valve on the by-pass loop to balance the system temperature.

Dave

 

[Sawyer]

Thanks Dave,

This will be used for radiant heating.

 

[in hot water]

Any valve with moving parts is prone to fail,or stick. Usually 3 way thermostatics valves used on domestic water applications are the ones that need to be maintained, often on a yearly basis. Hard water, minerals, etc tend to scale up the internals. Most plumbers install them so they can be easily serviced, and keep a spare rebuild kit on the truck.

The key is to assure you clean and flush your system, ideally with a hydronic cleaner, to lessen the potential for valve failure, or sticking.

It's a fairly simple valve inside a spring, diaphragm and heat sensitive wax cartridge, similar to a thermostat used in automotive applications.

Any serviceable component on your system should have isolation valves nearby. This prevents draining down the system for repairs and maintenance.

Any time you drain down and refill you are adding fresh water/ O2 into the system with accelerates corrosion.

hr