Aga: controlling the hot water output

[daveproject]

The house we have moved into has an Aga. This has a water outlet used as a secondary water heat source - secondary to the main boiler. It also feeds a small radiator. This is a conventional, open vented, gravity system. The large bore piping used must be a major source of heat loss.

Is it possible/ safe to install a control valve in this pipe work just outside of the Aga. The objective being to cut of the gravity circulation when this secondary water heating is not required? Might there be any overheating or safety issues. Should the control-valve be in the cold return - expansion tank pipe or in the hot output - overflow side.

All advice appreciated.

 

[Terrywookfit]

No !!
The reason for large bore pipe work on an AGA is because of the poor flow rates !!
Any valves on the flow or return will make the appliance very dangerous as the heat source cannot be turned off automatically by the appliance!!

The boiler on it is only very low output any way!

 

[giblets]

No, you must not restrict the flow of water as there is no thermostatic/safety control on the Aga. The only place you could possibly put the valve is on the connection to the cylinder leaving the radiator in the permanant circuit and turned on all year round to act as a heat shunt. The hot water produced by the Aga should be regarded as the primary hot water scource and the boiler regarded as the secondary one as the boiler can be turned off. On our Aga we only use the boiler circuit when we have folk to stay.

TBH if you have an Aga the heat loss from the primary pipes will be the least of your worries. Hope you have plenty of money for the gas/oil bills.

 

[daveproject]

My thanks to Terrywookfit & giblets for their advice. Seems obvious now that just restricting the flow would cause the heat-exchanger in the Aga to boil or worse. Checking on the Aga web-site it may be possible to have the Aga modified to remove the water heating element. This could potentially save a grat deal of energy (CO2).

My prefered solution wout be to get rid of the Aga - however that would result in divorce!

Daveproject

 

[oilman]

You could remove the Aga "boiler". It means the top has to come off. The Aga would be better without it anyway. Any appliance cannot cook and heat water efficiently as they require very different temperatures.

 

[giblets]

My prefered solution wout be to get rid of the Aga - however that would result in divorce!

I know the feeling but as my wife actually bought the bloody thing I'm a tad stuffed.