Hot Water Robbing CH?

[roberta1000]

I had my boiler replaced last summer. Previous system was gravity hot water. The HW tank is very close to the boiler and the piping is the original 28mm apart from a foot or so coupling to the flow and return.

When the HW is heating, the radiators cool quite a bit. Also the boiler modulates down at the same time even though the heating is on. I think it's likely a balance problem with the HW circuit taking most of the flow. Meantime I'm timing the HW to be on when the CH is off but I think that overall that will use more gas (?).

Is it possible to fit a restricting valve in the HW circuit? Can I get something suitable in 28mm or should I fit a section of narrower bore? If I fit a valve would I balance it by trial and error or similarly to the radiators? Thanks.

 

[Dan Robinson]

A 28mm gate valve is needed.

 

[roberta1000]

Thanks, I'll get one. Awkward placed and big rigid pipes to fankle with but no chance of a plumber for such a small job.

 

[ALEC1]

heating hot water and a house to set temperatures is pretty much a zero sum game...the down side is the discomfort or heating not working properly.

another big mistake that people make is not having the hot water set temperature a good 10c below the boiler temperature, so the cylinder takes ages to shut down if at all..

that may solve your problem, worth a try any way!