I have a hot water system that runs off the oil fired boiler directly. The landlord changed the mixing valve in the bathroom shower and now I can't control the water temp its constantly changing from boiling hot to cold and if you open the valve all the way it seems the boiler can't make hot water fast enough. Is there such thing as a valve specifically for boiler fired hot water systems? Why is the temp so random? Please help!

Hi BB

How is the hot water at other fixtures? If hot water temperatures are fine/balanced at the other fixtures then it could be that the balancing spool of the new mixing valve (shower valve) is defective... should be a simple cartridge replacement and in most cases the part will be under warranty!

Talk to your landlord and if he/she did nothing besides swap out the mixing valve at the shower then most likely a replacement spool/cartridge is needed here.

Back to you...

Mark

There should be a mixing valve installed at the boiler.

Hi Grady

Not necessarily so... ;) If this is a tankless coil directly off the boiler then yes, it should have a tempering valve, but if it is an indirect storage tank then in most states a tempering valve is not required.

With that being said, without more info. it seems to me that the shower valve itself may be the issue especially seeing how Bareback didn't mention problems with any other fixtures

Hopefully he/she will return and provide more information!

Mark