Declining Megaflow capacity

[jezza]

Hello all,

Customer has an old Megaflow, the type with a white top, and is complaining that she is getting less hot water than she used to, gradually. The property has 2 of these, the other one is located elsewhere, and is working fine.

The problem cylinder is located at the far end of the property, some way from the other, and most likely gets less use. All external controls are working just fine (indirect, both cylinders on same programmer channel but separately zoned) . The water, that there is of it, is plenty hot enough. Once it has been exhausted, recovery time is also decent. Primaries nice and hot. I haven't as yet measured exactly how much hot water is available , but have emptied the cylinder and inspected the inside and all is clear. I did this as there is also a direct cylinder on a separate system which got clogged up with scale a couple of years ago, causing a similar problem.

Any suggestions?

Many thanks,

Jezza

 

[kris]

Take it your a g3 man jezza. Is incoming to cyl ok

 

[Best]

When you say less hot water, I assume you mean less total volume available & not the flow at taps?
Is any of the relief valves passing water?
Or are there any hot taps or showers running water? (You could check that by turning mains completely off to unit & testing hot pipework for a pressure drop.)

 

[kris]

I thought he was on about less at tap as in flow but if volume then ignore my last post. Lol

 

[Best]

I think it is confusing - declining capacity, is the title. I thought reduced flow of water would have been more likely, due to blocked inlets or outlets or filter on combined PRV.
If it is flow, then ignore my first post! :smile:

 

[Ermintrude]

Check stats. Is it possible primaries a mess, 2 port slightly blocked if it's miles away it might be getting robbed of heat ? Primary pump ok? The cyl will heat fine on first cycle as its got all the time in the world so leave it for 24h check vol.

Discharge Nd check vol. I bet it's not getting sufficient heat delivered. Baffles not stuck . If units the same swap the stats over. To check

 

[jezza]

Thank you all, much appreciated.

Just to be clear (sorry), problem is quantity of HW. Stat works, 2 port replaced 2/3 years ago and works. Cylinder is a long way from valve though, but primaries at cylinder hot. Pump OK and other HW zone has no probs, also gets much more use..

However, and I was wondering, this cylinder serves 2 bathrooms, one rarely used, the other regularly. The hot tap on the bath drips constantly, I estimate approx. 1litre/hour. The cylinder is 210 litres, and HW is on constant. The only reason that I haven't replaced the hot tap washer is the size of it (about 45mm), so I must do this, but nevertheless as the HW is on 24hrs I dismissed this as a possible cause. Am I wrong?

Thanks all once again,

Jezza

 

[jezza]

Check stats. Is it possible primaries a mess, 2 port slightly blocked if it's miles away it might be getting robbed of heat ? Primary pump ok? The cyl will heat fine on first cycle as its got all the time in the world so leave it for 24h check vol.

Discharge Nd check vol. I bet it's not getting sufficient heat delivered. Baffles not stuck . If units the same swap the stats over. To check

Thanks Ermintrude,

I was wondering about the baffle.. If it gets stuck can it cause this problem? The cylinder is quite old.. No discharge. Primaries good and hot. Recovery time good but quantity of water maybe 2/3rds what it ought to be.