Downstairs radiators don't get hot when water is on

[dave964]

Hi,
When I woke up this morning, I discovered I had no hot water. The boiler had apparently overheated over night - so I used the reset switch.

It fired up fine, and I turned the water and heating on. The water seemed to heat OK - and the upstairs rads got hot. But the downstairs ones stayed cold.

The pump definitely seems to be working. I tried increasing the speed from 1 to 2 (it's a Myson SMC SD52) but that doesn't seem to make much difference.

The one thing that does make a difference is the hot water. If that's on (i.e. heating) the dowstairs rads will stay cold. If it's off, the downstairs rads will heat up.

I suspect the pump - it's almost like it can't handle the hot water system and the heating at the same time. But surely pumps either work or don't work?

 

[Agile]

Your pump is very old and may well be running very slow.

If its the old flattish type of pump then you cannot do the finger test.

Since a new pump is so cheap and the old one well time expired then whats the problem in getting a new one?

You could even get a cheap DAB one for less than £30.

Tony

 

[dave964]

Thanks for the answer.

If it's likely to be the cause, then I'm happy to replace it. Will look into it tomorrow.