combi system require radiator open loop?

[ziqpy]

I have a worchester 24CDi combi boiler.

My question is regarding the central heating. All my radiators bar 1 have a indervidual thermastat on.

Now when the heating is on, the boile fires none stop. Do I require that 1 radiator with no termastat on it?

 

[migoplumber]

all boilers require a constant flow of water through part of the heating cct, or a bypass between flow and return. without this the water temperature gets too hot and the boiler safety interlocks shuts doen the boiler

this is generally achieved by leaving 2 lockshield valves open on the bathroom rad

if your boiler is on constantly, try lowering the temperature on the c.h. circuit

if this fails to work, you may need to replace your flow sensor, and will probably have the pressure relief valve on a sealed system or tank over flow on open system discharging water outside

good luck
shaun

 

[ziqpy]

yes the radiator used as the loopback is a small rad with 2 shieldlocks. I would not say it's a faulter sensor as the house size makes it generally cold.

Taking into accout that the heat exchange rate of the loop radiator is causing the boiler to fire constantly, would it be ok to adjust the shieldlocks and reduce the water flow by say 1/3? Without setting off the boild safety?

 

[migoplumber]

im assuming its a sealed system.

rather than turn the lockshields down, turn the boiler temperature down first

are all the other radiators off and cold?

what happens if you turn the central heating off, does the boiler stay on?

how many pipes are running into the boiler?


shaun

 

[ziqpy]

Only 1 radiator + loop is used. Rest are thermostat'd off.

Boiler does not fire when heating is turned off.

 

[migoplumber]

so why not just turn the boiler from winter to summer setting, sounds like the boiler is working fine!

shaun

 

[ziqpy]

thx for the advice.

 

[Jay_1981]

no no bypass rad is required as an internal bypass is fitted in the boiler, that said it is best practice to leave one rad as a bypass. hope this helps sorry its a little late

 

[leakylea]

a boiler firing up has no bearing on the output is giving,a modern boiler may well work out that it is more efficient to remain lit at a very slight output, than to switch off and have to reheat the water content to the required temperature
I had an Ideal istor that was lit nearly contiuosly whilst it was on timer, when checked it was working perfectly.