Pipework advice - Central Heating System

[Desktop987456]

I took the plunge on Sunday on extending and connecting my pipework from front boiler. We layed the 50ft length of 20mm copper pipe (.8 inches inner dia), my pipe work is 20mm going out from boiler and then

reduces to 15mm going into radiators in each room. After extending the pipework to 50ft, I split the pipes going on back side rooms and upstairs and made two zones by installing a manual valve. I am not utilzing downstairs rooms at the back so we shut off the valve. I had doubts that I may need to install a pump as it may not cope up with the requirements of upstairs rooms but to my surprise the upstairs bedrooms heated up quickly than front ones despite running 50ft from boiler to the back and then further 10ft upstairs. The boiler now has 12 radiators connected to it.
I haven't tested the other zone (downstairs) yet but boiler is consuming more gas; it stays on for 10 minutes and then off for 5 minutes, previously it used to stay on for 6 mins and then off for 8-10 mins.

One issue I see is that the plumber made a connection to 50ft extension first on the flow and return line coming from boiler; so it is heating more quickly but others are taking time (front side rooms upstairs and downstairs).

Question : Should I install a bigger pipe 25mm or 1inch inner diameter pipe coming out of the boiler and then make connections to newly installed pipes and others which are 20mm now? So I can get even flow to all the radiators.
Thanks

 

[gmartine]

You should be able to balance the radiators manually to ensure they roughly heat up at the same rate. Your plumber should be able to do that.

 

[Desktop987456]

but boiler is consuming more gas

Thanks as always for your help. My central heating system is working fine now, the radiators are balanced. I have noticed that boiler is staying on or lit longer; about 12 minutes on and 8 minutes off so it cycles 3 times in one hour.
Before this extending pipework, my gas usage was 0.9units per hour but it has gone up to 1.5units per hour? The sensor that controls the burner is attached with Return pipe. Would it make any difference to attach it with flow pipe? Just thinking that with this recent extension of pipework the returned water to boiler is taking a lot longer so burner is staying on a lot longer?
Any clues or pointers? Thanks

 

[gmartine]

Increase in gas use sounds about right doesn't it? To improve efficicency and therefore consume less gas lower the flow temp as much as possible to be comfortable which will also increase burn time but at a lesser gas rate.

Do not move the sensor.

 

[Desktop987456]

Increase in gas use sounds about right doesn't it? To improve efficicency and therefore consume less gas lower the flow temp as much as possible to be comfortable which will also increase burn time but at a lesser gas rate.

Do not move the sensor.

Its a non condensing simple boiler with two solenoid valves to control the gas flow and a bigger burner below the heat exchanger. The thermostat and its sensor is attached to Return pipe, the burner is lit at 41degC and goes off at 45degC. I was thinking that my be if I attach the sensor to flow pipe, would it change anything?

 

[ShaunCorbs]

What boiler is it ?

 

[Desktop987456]

It is non condensing locally made boiler as I am not in UK.
The return lines of the extended section (old pipwork) has lost some of the insulation material and is exposed to outside temperature, does it affect how long the burner is on?

 

[Desktop987456]

Increase in gas use sounds about right doesn't it? To improve efficicency and therefore consume less gas lower the flow temp as much as possible to be comfortable which will also increase burn time but at a lesser gas rate.

Do not move the sensor.

Thanks for your comments. The sensor was slightly off from the pipe which wasn't give accurate reading. Now sorted the sensor and gas usage on hourly basis is 1.1 units per hour which was just about what I expected after extended pipework and radiators. Thanks for everyone's help.