We have 3 new vertical single panel radiators 7ft ish tall( they look
like MYSON DECOR V10 rads) - two upstairs and one downstairs in an
extension that the previous owners added onto a property we have just
moved into. These rads take ages to heat up, when all the other
traditional rads are hot (including 2 small trad rads also in
extension) these are still luke warm/cold. The lockshields have all
been fully opened to try help this problem but with no avail. It seems
the pipework is getting warm/hot but the flow of this water around the
rads is just so slow.

1.Could it be because the rads are so tall? (gravity problem), or pump
not coping with these? Any ideas?

The heating system is via 2 pipe indirect with oil boiler, pump 15/50
ups grundfos, 3 way valve (I think Honeywell Y plan) with water tanks
in roof.

2.I have been told that the bearings on the pump may be beggining to
go and that the pipework of hot water feed from pump to radiators is
only 15 mm and should be 22mm. Do you know if 15mm is standard and
sufficient, for 3 bed house, 9 rads?


Simon

On 4 Nov 2004 02:56:17 -0800, (Simon L)
wrote:

We have 3 new vertical single panel radiators 7ft ish tall( they look
like MYSON DECOR V10 rads) - two upstairs and one downstairs in an
extension that the previous owners added onto a property we have just
moved into. These rads take ages to heat up, when all the other
traditional rads are hot (including 2 small trad rads also in
extension) these are still luke warm/cold. The lockshields have all
been fully opened to try help this problem but with no avail. It seems
the pipework is getting warm/hot but the flow of this water around the
rads is just so slow.

1.Could it be because the rads are so tall? (gravity problem), or pump
not coping with these? Any ideas?

The heating system is via 2 pipe indirect with oil boiler, pump 15/50
ups grundfos, 3 way valve (I think Honeywell Y plan) with water tanks
in roof.

2.I have been told that the bearings on the pump may be beggining to
go and that the pipework of hot water feed from pump to radiators is
only 15 mm and should be 22mm. Do you know if 15mm is standard and
sufficient, for 3 bed house, 9 rads?


Simon


You can't really determine fow in terms of the number of radiators.
You have to look at individual capacities. Broadly, though, in a
typical house environment, 15mm tube will carry enough water to heat
6kW of radiator. You can do a simple sanity check on that from the
manufacturer data sheet for the radiator size.

You could try increasing the pump setting but also reduce the
lockshield settings on the radiators that are getting warm.
Take a look at the FAQ and section on balancing. The object is to get
more water flowing in the larger radiators that are not warming up




--

..andy

To email, substitute .nospam with .gl

The lockshields have all been fully opened to try help this problem
but with no avail.

You need to do a full balancing before you go any further. You'll need an IR
non-contact thermometer and the FAQ off Ed Sirrett's sig.

Turning up the valves on the new rads is not enough if the existing rads
also have theirs wide open, as those ones might hog the flow.

Christian.

Andy Hall wrote in message . ..


You can't really determine fow in terms of the number of radiators.
You have to look at individual capacities. Broadly, though, in a
typical house environment, 15mm tube will carry enough water to heat
6kW of radiator. You can do a simple sanity check on that from the
manufacturer data sheet for the radiator size.

Thanks for the info - will check rad kw stats (i take it you mean 6kw
total for all rads?)


You could try increasing the pump setting but also reduce the
lockshield settings on the radiators that are getting warm.

The pump setting is already at max. The rads close to cylinder have
their lockshields closed down more. This was done recently and did
help but not suffiently enough to get the big vertical rads hot
quickly. The pump has suspect bearings so I have been told - would you
say a Grundfos 15/50 UPS (not sure what the figues mean) a direct
replacement, sufficient power/type for my CH - 22mm return, 15mm feed,
9 rads, 3 of them 2m vertical type?

Once again, thank you for your comments.

Simon