Some radiators take ages to heat up and not fully hot

[jeffsteinson]

I don't knwo if anybody has ever come across this problem before: but some of my radiators seem to take ages to heat up, whilst others are quicker. I had a plumber come round who said it waqs weird, and he tried balancing the system and although some got a bit warm, nothing major happened. He said the hot water (when on with the heating) was starving the radiators. Some of the radiators in my house (2 downstairs) are new (ish) - installed 4 years ago, and have never heated to the mx temp and have always taken ages.
Is there anything I can do or is it just down to bad design?

 

[Slugbabydotcom]

Probably needs a balancing valve on the primary return from the cylinder. OK your rads are balanced but when the diverter is in the mid position then there is less resistance to the flow of water through your cylinder than the CH side.

 

[andytheplumber]

New house

 

[jeffsteinson]

is a balancing valve the same as having a gate valve installed on the primary return from the hot water tank (as some older systems had)? where can you get them from if gate valve's won't do?

 

[Slugbabydotcom]

A balancing valve is basically a gate valve with the red wheel head removed so no one tampers with it.

 

[Agile]

Wonderful, others are advocating the lockshield on the HW coil connection.

To me thats essential but few people seem to realise this.

I suspect the additional rads were piggy backed on existing 15 mm heating pipes which are too small to take the power expected. About 3 kW max on 15 mm.

There are many "plumbers" who are not very good at balancing rads.

Try turning down the lockshields on your hottest rads by 1/2 a turn at a time. Repeat that until they are no longer the hotest! Leave about 30 min between every adjustment to allow the system to stabilise.

A contact or non contact IR thermometer helps. Presumably your "plumber" did not have anything like that? He is probably one of those who learnt it from his father and has never been on a modern course! Not that many courses are that up to date anyway.

Tony

 

[markbro]

u might have sludge in the rad which will take longer to heat up. If its cold near the middle/bottom of the rad it's sludge if its cooler at the top, its air. if after hosing out its still cooler, it will be balance or a new rad. use a different rad from elsewhere to see if it warms up quiker, if it does u need a new rad