slow tmv

[duffin]

I regularly service an old people's home to fix the scaled-up and sticking tmv's. But one or two rooms take their time in getting a supply of hot water. the problem is the system is gravity with multiple cylinders for the unit and thers rooms are on the end of a run. the staff tell me the tmv is faulty when in reality the water is no longer in the pipe. is there any type of non-return valve made for gravity flow or are they all high pressure?

 

[Boilerman2]

Are you sure there isn't a Hot Water Secondary Pump not working somewhere?? perhaps near the hot water cylinders?

 

[Onetap]

But one or two rooms take their time in getting a supply of hot water. the problem is the system is gravity with multiple cylinders for the unit and thers rooms are on the end of a run.

There should be a working secondary circulation system, as Boilerman's post. There should also be hot water discharged from the tap within 60 seconds, otherwise it is a forseeable legionella risk. Is ther a legionella assessment in place for the property? The managers re otherwise exposing themselves to a very big risk of being sued.
I suspect DP will be along to rubbish this shortly; if so, that's because he knows nothing about legionella.